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Sensory Processing Sensitivity: A Review in the Light of the Evolution of Biological Responsivity

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Abstract

This article reviews the literature on sensory processing sensitivity (SPS) in light of growing evidence from evolutionary biology that many personality differences in nonhuman species involve being more or less responsive, reactive, flexible, or sensitive to the environment. After briefly defining SPS, it first discusses how biologists studying animal personality have conceptualized this general environmental sensitivity. Second, it reviews relevant previous human personality/temperament work, focusing on crossover interactions (where a trait generates positive or negative outcomes depending on the environment), and traits relevant to specific hypothesized aspects of SPS: inhibition of behavior, sensitivity to stimuli, depth of processing, and emotional/physiological reactivity. Third, it reviews support for the overall SPS model, focusing on development of the Highly Sensitive Person (HSP) Scale as a measure of SPS then on neuroimaging and genetic studies using the scale, all of which bears on the extent to which SPS in humans corresponds to biological responsivity.
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DOI: 10.1177/1088868311434213
published online 30 January 2012Pers Soc Psychol Rev
Elaine N. Aron, Arthur Aron and Jadzia Jagiellowicz
Sensory Processing Sensitivity: A Review in the Light of the Evolution of Biological Responsivity
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Psychologists (e.g., Gosling, 2001) have looked at personal-
ity differences within animal species to confirm in an inde-
pendent context some of the personality differences found in
humans, finding extraversion and neuroticism particularly
easy to observe reliably in mammals and to explain in
humans from an evolutionary perspective. This article looks
at the reverse by seeking in humans somewhat different basic
traits that evolutionary biologists studying animal personal-
ity have delineated, as well as applying the thinking of
these biologists to the evolution of human personality traits.
Specifically, this article reviews the research on the trait of
sensory processing sensitivity (SPS; E. Aron & Aron, 1997)
in the light of the evidence from evolutionary biology that
many personality differences in nonhuman species (e.g.,
goats, Lyons, Price, & Moberg, 1988; great tits, Verbeek,
Drent, & Wiepkema, 1994; pigs, Hessing, Hagelso, Schouten,
Wiepkema, & Vanbeek, 1994) involve being more or less
responsive, reactive, flexible, or sensitive to the environment
(Dingemanse, Kazem, Reale, & Wright, 2009; Wolf, Van
Doorn, & Weissing, 2008).
After briefly defining the SPS trait and model, this article
first discusses how biologists studying animal personality
have conceptualized this trait of a general sensitivity to the
environment; second, reviews research on human personal-
ity and temperament differences that, although usually not
designed to do so, strongly suggests this general sensitivity;
third, reviews support for the SPS model focusing on
development of the Highly Sensitive Person (HSP) Scale
(E. Aron & Aron, 1997) as a measure of SPS, and neuroim-
aging (e.g., Jagiellowicz et al., 2011) and genetic (Licht,
Mortensen, & Knudsen, 2011) studies using the scale, all of
which bears on the extent to which SPS in humans corre-
sponds to biological responsivity.
SPS (unrelated to “Sensory Processing Disorder,” e.g.,
Bundy, Shia, Qi, & Miller, 2007) is proposed to be a geneti-
cally determined trait involving a deeper (in the sense of
Craik & Lockhart, 1972) cognitive processing of stimuli that
is driven by higher emotional reactivity. Direct genetic
encoding of depth of processing is not the only possible path
to differences in this or any other personality difference.
General personality differences can be related to many factors,
including of course the physical and social environment,
development of specialized skills through experience using
them, and as a side effect of other inherited traits such as
growth rate in nonhuman animals (Stamps, 2007) and body
size and strength in human extraverts (Lukaszewski &
Roney, 2011). But from the outset (E. Aron & Aron, 1997)
we have seen SPS as the manifestation in our species of one
434213PSRXXX10.1177/1088868311434213Aron
et al.Personality and Social Psychology Review
1State University of New York at Stony Brook, USA
Corresponding Author:
Elaine N. Aron, Department of Psychology, State University of New York
at Stony Brook, Stony Brook, NY 11794-2500, USA
Email: aron@ic.sunysb.edu
Sensory Processing Sensitivity:
A Review in the Light of the Evolution
of Biological Responsivity
Elaine N. Aron1, Arthur Aron1, and Jadzia Jagiellowicz1
Abstract
This article reviews the literature on sensory processing sensitivity (SPS) in light of growing evidence from evolutionary biology
that many personality differences in nonhuman species involve being more or less responsive, reactive, flexible, or sensitive
to the environment. After briefly defining SPS, it first discusses how biologists studying animal personality have conceptualized
this general environmental sensitivity. Second, it reviews relevant previous human personality/temperament work, focusing
on crossover interactions (where a trait generates positive or negative outcomes depending on the environment), and
traits relevant to specific hypothesized aspects of SPS: inhibition of behavior, sensitivity to stimuli, depth of processing, and
emotional/physiological reactivity. Third, it reviews support for the overall SPS model, focusing on development of the Highly
Sensitive Person (HSP) Scale as a measure of SPS then on neuroimaging and genetic studies using the scale, all of which bears
on the extent to which SPS in humans corresponds to biological responsivity.
Keywords
personality, sensory processing sensitivity, biological responsivity, highly sensitive person, temperament, animal personality
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2 Personality and Social Psychology Review XX(X)
of two strategies that have evolved in many other species as
well. Although these two strategies may in fact be continu-
ous, they are more easily described in terms of either respond-
ing more to the environment or responding less. Responding
more to cues in the environment by comparing them (con-
sciously or not) to past experience with similar cues may
result in taking more time to observe and reacting less rap-
idly, and thus appearing less “bold” or impulsive and more
risk averse, especially in novel situations or when there are
conflicting action tendencies (approach–withdraw). After
having observed, however, a responsive strategy could result
in behaving in an especially bold or at first glance risky (but
in fact not risky) manner in the future because in similar situ-
ations there would be greater certainty about how to behave.
Still, the strategy of greater sensitivity is often named for
easily observed behaviors related to pausing to process, such
as withdrawing, while missing what may be the underlying
cognitive behavior, which we see as a common difficulty for
research on this trait in human personality.
We have proposed (E. Aron & Aron, 1997) that in humans
the more responsive strategy is partly characterized by being
more prone to “pause to check” in a novel situation, being
more sensitive to subtle stimuli, and employing deeper or
more complex processing strategies for planning effective
action and later revising cognitive maps, all of which is driven
by stronger emotional reactions, positive and negative. The
role of emotional reactivity was not made explicit in 1997,
but reflects findings then and later (e.g., E. Aron, Aron, &
Davies, 2005), as well as fitting the view that emotionality
facilitates learning and memory by providing feedback and
retrospective appraisal (Baumeister, Vohs, DeWall, & Zhang,
2007). Similar processes involving the intertwining of reac-
tivity and depth of processing can also be seen in nonhuman
animals (e.g., rodents, Koolhaas et al., 1999; fish, Schjolden
& Winberg, 2007; and birds, Groothuis & Carere, 2005).
The Possibility of a “Meta-
Personality” Trait of Sensitivity
or Responsivity to Context
The identification of animal “personalities” that are consis-
tent over time and extend to various contexts (e.g., Gosling
& John, 1999; Sih & Bell, 2008; Sih, Bell, & Johnson, 2004;
Stamps & Groothuis, 2010) has spurred theorizing about
why and how these differences evolve. Some of the first
speculation was done in a groundbreaking study by Wilson,
Coleman, Clark, and Biederman (1993) in the report of their
study of pumpkinseed sunfish, in which individuals from the
same pond varied on a continuum from shy to bold behav-
iors. Behaviorally “bold” fish were initially identified as
those caught in a trap, a novel object in their environment.
Behaviorally “shy” fish did not enter the traps and were
captured by net. The trait continuum was found to be consis-
tent across time and in other contexts, in that compared with
the trapped fish, shy (had to be netted) fish were slower to
acclimatize to the lab, and in the pond swam closer to other
fish and were less likely to approach (or more likely to flee
from) a human observer in the water. The two groups also
differed in what they ate, the quantity of parasites in or on
their bodies, and where in the pond they could be found
(bold fish in open water), suggesting a stable difference in
genotype. However, as the shy fish acclimatized to the
laboratory with time and stopped behaving shyly, it was
also speculated that they were evidencing a broader trait of
responsiveness to the environment.
Wilson and colleagues (1993) pointed out that two pheno-
types for foraging behavior could theoretically emerge when-
ever a risk-free habitat fills up with fish and some individuals
must move to riskier habitats. Hence, shy fish may have been
initially aggressive and driven other fish into open water, forc-
ing them to adapt to that environment by behaving boldly.
These “shy” fish in other contexts turned out to be more curious,
exploring a stick more than other fish, again suggesting there
were in fact more responsive (Coleman & Wilson, 1998). Note
that a responsive strategy’s success is negative-frequency depen-
dent, in that it depends on how many others are using it. When
too many use it, it ceases to be adaptive. Individuals capable of
responding by taking up another strategy would have an advan-
tage over those inheriting only one behavioral response such as
only avoiding open water or only avoiding any new object.
A decade later, responsivity, or sensitivity across time and
contexts had been found in enough species to generate theo-
ries about a general trait of sensitivity or responsivity to the
environment (Gosling, 2001; Korte, Koolhaas, Wingfield, &
McEwen, 2005; Sih & Bell, 2008; Wolf et al., 2008; Wolf,
Van Doorn, & Weissing, 2011). Personalities had been iden-
tified in more than 100 species, from insects to mammals
(Sih et al., 2004), and Wolf et al. (2008) noted that “Many
researchers believe that a fundamental factor structuring
[animal] personality differences is the degree to which
individual behavior is guided by environmental stimuli”
(p. 15835). For example, Koolhaas and colleagues (1999), in
their overview of differences in aggressiveness in several
bird and mammal species, observed that in fact, an equally
good candidate for being a “fundamental difference seems to
be the degree in which behavior is guided by environmental
stimuli” (p. 927). As an example, they noted that in certain
bird species aggressive males easily develop routines, appear-
ing to be driven and rigid, whereas nonaggressive males “are
more flexible and react to environmental stimuli all the time”
(p. 927). That is, the easily observed behavior of aggression
versus nonaggression might hide a more fundamental differ-
ence of responsive versus nonresponsive. By observing aggres-
sive behavior and avoiding it, nonaggressive individuals may
be exhibiting one aspect of their broader responsiveness.
In a similar vein, Sih and Bell (2008) wrote that enough
examples exist “to suggest that individual difference in envi-
ronmental and social sensitivity is common, potentially quite
important, and worthy of further study” (p. 16). Dingemanse
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Aron et al. 3
and colleagues (2009) provided an integrative model for
observing personality traits (e.g., shy, bold, aggressive, non-
aggressive) that in some species or individuals are inflexible
and completely specific to context but in other cases are flex-
ible, occurring in some contexts and not in others, accord-
ing to its usefulness, so that the underlying trait in these
cases would be being sensitive enough to know when to
be shy, bold, etc.—suggesting layers of processing.
Stamps and Groothuis (2010) are wary as to whether there
is sufficient evidence in animals to demonstrate a “meta-
personality” trait of contextual sensitivity but also acknowl-
edge that such a trait
could lead to major changes in the way we think about
the organization of behavior . . . that some consistent
individual differences in behavior are so pervasive as
to affect the ways that individuals interact with the
external world in a wide range of motivational or func-
tional situations. (p. 316)
Noticing and responding to subtle changes in an environ-
ment might seem always to be advantageous, but in fact sen-
sitivity to subtle differences can be a costly endeavor. Time
and energy must be taken away from foraging, for example,
and be used to observe and also to maintain the necessary
biological apparatus, especially the “reactive” coping style
by which most responsive animals are identified. Moreover,
again, the benefits of being responsive depend on how many
others in the environment are responsive. Wolf et al. (2008),
using computer and mathematical simulations, investigated
situations in which individuals in a population are confronted
with choices in a changing environment (e.g., can choose
between two food patches and the quality of patches changes).
Individuals can follow either a responsive or an unrespon-
sive strategy. Responsive individuals take into account cues
about their environment (e.g., cues as to which of a number
of patches is better). Consequently, responsive individuals
can exploit opportunities in their environment better than
unresponsive individuals (e.g., the quality of patches may
change over time and responsive individuals, as they take
into account environmental cues, will be better able to iden-
tify which patch is best at a given point in time). However,
the value of resources depends not only on their inherent
value (e.g., how many resource items are in a patch) but also
on the number of competitors for that resource. The more
responsive individuals there are around, the lower the value
of these opportunities, as more individuals (all responsive)
compete for them. This gives rise to negative-frequency
dependence, which in turn promotes the coexistence of a
minority of responsive individuals along with the majority of
non (or less) responsive individuals. That is, the responsive
strategy is an advantage only as long as most individuals do
not use it, as when a short cut to avoid a traffic jam is useful
only as long as most people do not know about it and consis-
tently use the usual route. Negative-frequency dependence,
in turn, predicts a polymorphism between responsive and
unresponsive individuals. In reality, unlike a simulation,
responsiveness might be a much more continuous trait,
depending on the exact payoffs, but even minor variations in
responsivity produce the same results. (Animal trait varia-
tions, including some types of responsivity, occur in other
ways, usually due to spatiotemporal variations: One type is
better in a particular area or at certain periods in the life span
of that species, e.g., years where there are more predators,
and the other type is more successful in other places or times.)
Wolf et al. (2011) expanded their work to repeated choices
in social interactions, showing that once some individuals in
a population are socially responsive, this can have substan-
tial effects on the outcome of the evolution for other traits,
creating selection pressures that lead to consistent individual
differences in, for example, aggressiveness and cooperative-
ness (Wolf et al., 2011) and trustworthiness (McNamara,
Stephens, Dall, & Houston, 2009). It is only useful to behave
consistently in any of these ways when another notices and
responds. In these models, consistent individual differences
proliferate once some individuals develop a trait of being
responsive. These models of how a very broad form of
responsivity or sensitivity might evolve are not fully tested
in nonhuman species, and Wolf et al. (2008), Sih and Bell
(2008), and Stamps and Groothuis (2010) cited research on
humans—our work on adults (e.g., E. Aron & Aron, 1997)
and that of Boyce and colleagues (1995), Boyce and Ellis
(2005), and Belsky, Bakermans-Kranenburg, and Van
Ijzendoorn (2007) with children—as a strong indicator that
such a “meta-personality trait” could exist in some species.
The Uncovering of
Sensitivity in Humans
A trait of broad sensitivity to the environment is indicated by
it being observed in a variety of settings or by finding inter-
actions, especially crossover interactions such that some
individuals more than others are found to vary their behavior
depending on their environment. Both of these, being broadly
observed and behavior x environment interactions, have
been seen in humans, as discussed below. A third line of sup-
port, especially for those studying human personality, would
be whether such a trait of general sensitivity has been
implied by prior personality research.
Observations
Observation of sensitivity in many environments is, again,
one way to identify a consistent personality difference.
Thomas and Chess (1977) in their early work on childhood
temperament (defined as a behavioral style, or a general way
of responding that is stable over time, and assumed to have
genetic origins; Kristal, 2005) observed low sensory thresh-
old (LSL) as one of the nine basic traits distinguishing chil-
dren. It, together with other traits such as social withdrawal,
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4 Personality and Social Psychology Review XX(X)
make up the personality of the slow-to-warm-up child.
Rothbart and Bates (2006) described children’s tempera-
ment with reference to two observable behaviors pointing to
sensitivity: Perceptual Sensitivity or awareness of subtle
stimuli as part of Effortful Control and Discomfort due to
intensity of stimuli as part of Negative Affectivity. We will
discuss this separation of sensitivity and affect later, but
what matters here is that at least a simple, easily observed
form of sensitivity, sensitivity to stimulation, has been
observed to occur across contexts and perhaps to underlie
groups of traits or consistent behaviors.
Self-reports are another way to obtain observations (albeit
self-observations) of behaviors consistent across time and
place, and much as we are all aware of the limitations of
questionnaires and interviews, these verbal behaviors are
unavailable to those studying other species (and ones they
probably envy). The first example of a self-report measure of
something like sensitivity is probably that of Mehrabian
(1976), who identified and developed a measure of low stim-
ulus screening. The second example is the HSP Scale (E. Aron
& Aron, 1997), the development of which we will describe
later in this article. Here, however, it is important to note
briefly that the development of the HSP Scale suggested a
much broader responsivity to the environment than simple
sensory sensitivity because this development began with a
purely exploratory and empirical study of what is meant
when the term sensitive is used by clinicians and the general
public to describe an individual. In the process of first inter-
viewing and then using items from those interviews to create
a measure, we found that such varied statements as being
highly conscientious, startling easily, having a rich inner life,
and being more sensitive to pain were all significantly cor-
related with each other. If sensitivity was such a broad phe-
nomenon, it seemed to require a broader theory than being
bothered by loud noises or itchy clothing and seemed to
extend beyond what we noticed at that time, that sensitive
persons reporting troubled childhoods were more introverted
and shy than those reporting relatively normal childhoods.
A third example of a self-report questionnaire measuring
behavior over a range of contexts is Evans and Rothbart’s
(2007) Adult Temperament Questionnaire, with facets of
Sensory Discomfort as part of negative affect and Orienting
Sensitivity, defined as attention to mostly subtle sensory
events: perceptual sensitivity (awareness of low-intensity
stimuli from the body and environment), affective perceptual
sensitivity (awareness of subtle emotional valence related to
low-intensity stimuli), and associative sensitivity (awareness
of other reactive cognitive content).
Interactions
The observation that some people are genetically more vul-
nerable than others to the effects of stress and a negative life
history has been recognized for some time, through obser-
vation or self-report in a variety of settings and through
interaction studies in particular. This has led to the trait
being named and studied as, for example, neuroticism, nega-
tive emotionality, vulnerability to depression, or inhibited-
ness. Any underlying trait of responsivity was largely missed.
The pioneering work on a trait approximating a general sen-
sitivity, Kagan’s (1994) work on inhibitedness in children, is
an example: Although it attempted to describe a neutral trait
and was seen to have some evolutionary advantages, it has
been mostly viewed as a precursor to various problems and
disorders (e.g., shyness and anxiety; Volbrecht & Goldsmith,
2010). Still, research on inhibitedness led to some of the best
observations of the processes (Gunnar, 1994; Nachmias,
Gunnar, Mangelsdorf, Parritz, & Buss, 1996) that might be
behind a crossover interaction—in this case one in which
persons carrying a trait thought to lead to vulnerability are,
compared with those without the trait, found to show better
outcomes in good environments, pointing to a broader trait
of responsivity to environments.
Crossover interactions have been essential for pointing to
sensitivity as the trait that is behind the vulnerability in many
cases, so that in the context of developmental psychology,
Belsky (2005) has chosen the term susceptibility to indicate
a “for better and for worse” outcome for children with cer-
tain plasticity markers (phenotypic behaviors, endophenotypic
attributes, or genotypes), depending on childhood environ-
ment. Although, traits seemingly the opposite of responsivity,
such as Attention Deficit Hyperactivity Disorder (ADHD),
have also been found to yield crossover interactions (Belsky
& Pluess, 2009). For example, researchers previously dedi-
cated to uncovering genetic vulnerabilities are now saying,
because of the increasing number of crossover interactions
being found, that “The most plausible explanation [for traits
and genes linked to psychopathology] is that environment
shapes the outcome of these fundamentally neutral common
genetic factors, leading to negative outcomes, but also hold-
ing the potential for positive behavioral manifestations”
(Homberg & Lesch, 2011, p. 513).
Early studies finding crossover interactions. Perhaps the
first relevant crossover interaction, and one definitely lead-
ing to a theory of general sensitivity, was found by Boyce
and colleagues (1995) in a study of respiratory illness in
children. Children with greater psychobiological reactivity
to stress, as measured by cardiovascular and immune reac-
tivity, and who were in a stressful child care (Study 1) or
adverse home environment (Study 2) had more illnesses
than nonreactive children, but those in low or minimal
stress environments had better than average outcomes.
Although the measure was stress reactivity, the authors
concluded that “one plausible explanation for such a pat-
tern of findings is the possibility that reactive children are
more sensitive or more susceptible to the characteristics of
the social environment” (p. 419). An earlier study of ado-
lescents (Gannon, Banks, Shelton, & Luchetta, 1989)
found similar results but did not discuss the implications of
the crossover interaction.
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Aron et al. 5
A crossover interaction implicating sensitivity was sug-
gested by studies of the interaction of parenting and tempera-
ment in conscience formation. Initially, Kochanska, Casey,
and Fukumoto (1995) found that children 2 and 3 years of
age who noticed flaws in objects shown to them during a
home visit were similarly more upset in a later laboratory
situation in which it was contrived that they would feel at
fault for breaking an object important to the adult with them
in the laboratory. Those who were aware of flaws during the
home visit were the most distressed and likely to attempt
reparations in the contrived mishap situation in the labora-
tory. Later Kochanska, Gross, Lin, and Nichols (2002) found
that children who were more inhibited in novel situations at
age 2 and 3 were also more upset in a situation again con-
trived to make it seem to them that they had caused a minor
mishap. At age 4 to 5 years, these children were less likely to
cheat, break rules, or be selfish when they had no fear of
being caught and gave more prosocial responses in moral
dilemmas. But in studies (Kochanska, 1997; Kochanska,
Aksan, & Joy, 2007) including parental child-rearing prac-
tices as a variable, inhibited children internalized moral
standards only when they had received gentle discipline
deemphasizing power, presumably resulting in an optimal,
moderate level of anxious arousal. When there was signifi-
cant power assertion, these children actually evidenced less
moral behavior at a later age. (In SPS theory, optimal level of
arousal is an important factor in the optimal functioning of
the sensitive strategy, as overstimulation can easily lead to
overarousal and poorer cognitive functioning.) For the rela-
tively fearless children, however, maternal responsiveness
and children’s security of attachment, more normative
requirements, were associated with internalization.
In sum, for inhibited, and by association presumably sen-
sitive children, the combination of awareness of subtleties,
emotional reactivity (or guilt after a mishap and more inhib-
ited behavior in the face of novel, highly stimulating situa-
tions), and awareness of consequences of behaviors for self
and others, all point to a more general trait of sensitivity
involving inhibition of behavior, emotional reactivity, sensi-
tivity to subtle stimuli, and processing of information to a
deeper level. However, when there is parental power asser-
tion, emotions and responses are no doubt to parental behav-
ior instead of to the subtler moral lesson to be learned from a
transgression.
Looking at adults and using the HSP Scale for the first
time in the context of a crossover interaction, E. Aron et al.
(2005) found an interaction with childhood experience in
three studies, and a nonsignificant tendency toward a cross-
over interaction in two of these, in spite of only measuring
negative affect. That is, among those scoring high on the
HSP Scale, those also reporting a troubled childhood on vari-
ous measures scored especially high on measures of negative
affect, but at the same time there was also a tendency for
those scoring high on the HSP Scale without such childhoods
to score especially low on measures of negative affect. Note
that although the measures of parenting were retrospective,
the pattern of results is exactly opposite to what might be
expected from biased recall or reporting. (In a replication of
this study, Liss, Timmel, Baxley, & Killingsworth, 2005,
found a similar pattern for parental quality of care and
depression, but not for parental overprotection and depres-
sion; there was only a main effect for anxiety.) In the first
direct experimental exploration of the possible processes
behind this interaction, E. Aron et al. (Study 4) set out to
evoke in college students an emotional reaction to either
good or bad feedback about their academic ability and found
that those scoring high on the HSP Scale had far stronger
emotional reactions, both for positive and negative feedback,
than those scoring low on the scale. Presumably, highly sen-
sitive children are similarly highly reactive to negative and
positive events during childhood.
Early experimental studies with nonhuman primates have
also yielded crossover interactions. Suomi (1997) cross-
fostered rhesus monkeys selectively bred to be high or low in
their reactivity. Reactive infants raised by average mothers
had the poorest outcomes, whereas those with low reactivity
showed little effect from being raised by either type of
mother. But the highly reactive infants raised from birth by
skilled, nurturing mothers had the best outcomes, in that they
showed developmental precocity, behavioral resilience to
stress, and ascension within the group’s dominance hierar-
chy, often becoming leaders, all of which suggests a greater
responsivity to social cues. Rhesus monkeys and humans are
the only primates with variations in the serotonin transporter
gene, which in both correlates with reactivity and yields this
same parenting × trait crossover interaction (Jedema et al.,
2009; SPS is also related to variations in the serotonin trans-
porter gene, Licht et al., 2011). They are also the most adap-
tive of all primates, suggesting it may in fact be an important
gene governing responsivity.
Theoretical developments arising from crossover interactions.
A special section of Development and Psychopathology (Vol.
23, 2011) was devoted to crossover interactions and theories
regarding them. Belsky and Pluess (2009) were able to iden-
tify 56 such studies, providing tables of those measuring phe-
notypes (e.g., anxiety, social fear, high SPS), endophenotypic
attributes (e.g., cardiovascular reactivity), and genotype (e.g.,
5-HTTLPR, s-allele). Many of these studies began with the
hypothesis that a certain trait led only to vulnerability but
reported results (sometimes failing to comment on them) of a
crossover interaction—positive environments or interven-
tions leading to positive outcomes—suggesting an underly-
ing sensitivity to the environment. For example, Gilissen,
Bakermans-Kranenburg, van Ijzendoorn, and Van der Veer
(2008) found that “temperamentally fearful” children in a
low-quality mother-child relationship were more distressed
by watching a fear-inducing film clip than were nonfearful
children in such a relationship. However, they also found that
“fearful” children in a high-quality relationship were less
physiologically distressed in the same situation than less
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6 Personality and Social Psychology Review XX(X)
fearful children with the same high-quality relationship. This
result suggests that terms such as temperamentally fearful
may be misleading in describing the trait under observation.
“Reactive” children have also been found to benefit more
from interventions. For example, Velderman, Bakermans-
Kranenburg, Juffer, and van Ijzendodorn (2006) found that
reactive infants, as rated by their parents, benefited more
(became more securely attached) than nonreactive infants
from an intervention designed to increase the responsiveness
of mothers, whereas in the control group, highly reactive
children were worse off than nonreactive children. Similarly,
Pluess and Belsky (2009) found that infants evidencing more
negative emotion (possibly a common response in sensitive
infants to overstimulation) were positively affected more
than other children by high-quality child care and more often
affected negatively by poor child care.
These results and others have spurred developmental psy-
chologists to look for evolutionary explanations for these
crossover interactions from life history theory (Kaplan &
Gangestad, 2005), which views each individual as faced with
the task of deciding (not necessarily consciously) how to
allocate energy resources across the life span so as to maxi-
mize successful reproduction. For example, if an individual
is living under dangerous conditions, the individual should
reproduce early in life so as not to lose the opportunity by
early death, and reproduce often in case some offspring are
lost because of these dangerous conditions. If living under
optimal conditions, however, the individual should wait until
full maturity so that offspring are maximally fit, and have
fewer offspring so that they are healthier and can make full
use of opportunities. Applying life history theory to humans,
Belsky, Steinberg, and Draper (1991) posited that the first
years of life provide a child with the opportunity to learn
through family and community experiences how stressful
the rest of the life will be and to time their reproduction
accordingly, a prediction borne out by studies of the timing
of puberty in girls living under adverse versus supportive
conditions (e.g., Ellis, 2004). Although the effect size is
small, it appears to be slightly stronger in hypothalamic-pitu-
itary-adrenal (HPA) reactive girls (Ellis, Shirtcliff, Boyce,
Deardorff, & Essex, 2011).Two theories have arisen regard-
ing how children vary in their responsiveness to environ-
mental cues that help with decisions regarding allocation of
energy resources. A theory of biological sensitivity to con-
text (Boyce & Ellis, 2005; Ellis, Essex, & Boyce, 2005) pos-
its that very early in life a high degree of HPA arousability
will be triggered in any child and be present throughout life
if the child detects either a highly stressful or highly support-
ive environment. This heightened reactivity helps individu-
als avoid danger in the stressful environment and make
optimal use of a supportive environment. Other children,
standing to benefit less from heightened awareness of their
environment, do not develop this reactivity. A theory of dif-
ferential susceptibility (Belsky, 1997) argues that variations
in responsiveness to childhood environment are innate and
due to the fact that parents who give birth to children with a
range of personalities, some sensitive and some not, are
more likely, to have some live to reproduce themselves than
parents with children having more uniform personalities.
When childhood conditions are good predictors of the
future, children sensitive to those conditions are better
adapted in adulthood; when childhood conditions fail to pre-
dict later conditions, nonsensitive children are better adapted.
Both theories predict a crossover interaction, but being
focused on childhood, have less to say about responsivity in
adulthood or the processes underlying it, beyond heightened
HPA reactivity. Indeed, the importance of infancy and early
childhood, HPA reactivity, and puberty timing suggests that
hormones are as important as neurons, and information pro-
cessing, whether thorough or superficial, according to indi-
vidual responsivity, is not only cognitive but also occurs
throughout the body.
Prior Research on Aspects
of a General Trait of Sensitivity
We have now considered observation of a consistent trait of
responsiveness across time and situations and trait × envi-
ronment crossover interactions as suggesting that a general
trait of sensitivity may exist in humans. We would also
expect that even though almost no thought had been given to
a general trait of sensitivity prior to 1997, it would be pres-
ent in some way within the vast amount of high-quality
research on human personality and temperament that has
accumulated for decades. This section reviews research on
traits that overlap with sensitivity in some way, in that in
some individuals these traits appear to act as an aspect of
sensitivity or as a result of it. One can imagine dozens of
ways that human personality might be designed to accom-
plish a general strategy of being more responsive or sensi-
tive that would be reflected in traits already under study. We
will discuss four of these: (a) inhibition of behavior, at least
in novel situations or in those generating conflicting responses,
in order to attend to potentially useful cues; (b) greater
awareness of sensory stimulation, so that more subtleties are
noted, but overstimulation is also possible; (c) deeper pro-
cessing of this sensory information, relating it to the past and
projecting its consequences into the future; and (d) stronger
emotional reactions, extending the elaboration of associative
processes, stimulating retrospective appraisal of actions,
promoting learning from and memory of important experi-
ences, and thus altering automatic guidelines for future
behavior, including more rapid automatic affective responses
(Baumeister et al., 2007).
This list is not complete. Sensitive persons might also
have more rapid and efficient unconscious processing, com-
monly called intuition; more useful dreams; or heightened
suggestibility. A genetically determined sensitivity would
not need to be restricted to the central nervous system either.
Persons who describe having the above four sensitivities also
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Aron et al. 7
tend to describe themselves as startling more easily than oth-
ers and being more affected by caffeine, pain, and medica-
tions (E. Aron & Aron, 1997). Biological sensitivity to
context is correlated with timing of puberty (Ellis et al.,
2011) and immune system reactivity (Boyce et al., 1995).
Children identified as inhibited in laboratory situations evi-
dence more allergic symptoms (Bell, 1992; Kagan, Snidman,
Julia-Sellers, & Johnson, 1991). But for the purposes of
reviewing a large body of personality research briefly, we
will focus on the above mentioned four. These four might in
theory represent separate ways of being responsive. However,
our research suggests that increased responsivity to the envi-
ronment involves most or all of these, while one of these in
isolation often does not signal a general sensitivity or respon-
sivity, and in fact may signal an impairment without evolu-
tionary advantage. For example, extreme sensitivity to
stimulation can by itself be a sign of Autism Spectrum
Disorders and suggest that something is interfering with the
type of higher processing required to sort through experi-
ences for their meaning.
The four listed above also are oversimplifications, at least
as behavioral indicators of SPS. For example, we cannot
expect inhibition of behavior in all or even most situations
involving responsivity because the current situation may
already be so familiar that there is no need to pause to check.
In this case, sensitivity might lead to a faster than average
response. This aspect also might better be termed inhibited/
planned behavior, in that responses already decided upon
can also inhibit behavior—sometimes prior experience dic-
tates that there is no need to act. Thus, the meaning of inhi-
bition and even its presence is questionable unless a sensitive
person is faced with a completely novel or unusually conflic-
tual situation, as when the relative costs of the usual choices
are higher than normal (e.g., situations when one has special
reason to fear judgment, leading to shyness; Aron, 2000).
Another example in which an aspect of SPS, emotional
reactivity, might vanish from view would be an individual
whose prior negative experiences with the expression of
intense emotions (e.g., sensitive boys crying on their 1st day
of school) has led to a precocious ability to under react
emotionally.
Inhibition of behavior. Again, this discussion of the inhibi-
tion of behavior is focused on whether sensitivity might be
the underlying reason for inhibited behavior in some indi-
viduals (and that inhibited behavior is not the best or only
underlying explanation of sensitivity). The evolutionary
function of the inhibition of behavior was of great interest to
Gray (1981), who initially described a Behavioral Inhibition
System (BIS) and a Behavioral Activation System (BAS),
the former being especially reactive to anxiolytics (anxiety
medications) and so equated with being more anxious, fear-
ful, and threat oriented. However, Gray (1985) quickly began
questioning the logic of equating the BIS with anxiety in that
it would mean that an individual would be more sensitive to
threat only. Even in 1981, he said such a function for the BIS
would “be tortuous, assuming it to be viable at all” (Gray,
1981, p. 270) because, if the task of the BIS were to compare
the present moment with the past (Gray’s [1985] formula-
tion) only to detect signs of threat or punishment, would it
not still have to examine all stimuli, not just threatening
ones? Furthermore, high BIS activity, if it were associated
only with anxiety, ought to be generally disorganizing, inter-
fering with the comparison process, but it does not.
Not surprisingly, Gray revised his theory (McNaughton &
Gray, 2000), and Amodio, Master, Yee, and Taylor (2008), in
describing more current thinking about the BIS, note that
unfortunately the conceptualization of the two as traits and
the measurement of BIS and BAS (e.g., Carver & White,
1994), developed earlier, have not reflected that change. In
brief, the BIS is now thought to produce alert interest and a
pause in activity that allows for the processing of conflicting
information, a balancing of or negotiation between the urge to
approach and satisfy needs (BAS) and the urge to stop and con-
sider risks, costs, or how best to make use of an opportunity.
In the case of threat, a third strategy of fight, flight, or freeze
is suggested. The greater the relative strength of the BIS sys-
tem as an individual difference, the more thorough would be
the processing of stimuli. A strong BIS would seem to be a
good candidate for supporting a trait of increased sensitivity
to the environment.
Zuckerman (1994), arguing from the side of impulsive
sensation seeking, suggested that in early evolution, organ-
isms could only approach (BAS) or withdraw (fight, flight,
or freeze), but the addition of an inhibition system added
flexibility and allowed for “further information processing in
organisms capable of such activity” (p. 241).
Building on Gray’s original theory, Kagan (1989), as
already noted, developed the term “behavioral inhibition to
the unfamiliar” (p. 1). Some of the standardized laboratory
settings and interactions for identifying inhibitedness include
a room with unusual objects such as novel toys or a strange
adult dressed in unusual clothing, spontaneous talking with
stranger peers, and speaking with an adult examiner (Kagan,
Reznick, & Snidman, 1988). Inhibited children are defined as
those who are slower to play, speak, or interact. Understandably,
given Gray’s early theory, Kagan related the trait to fearful-
ness and the amygdala. The usual assumption in this work is
that this is an indication of fearfulness. Indeed, studies of
inhibited children have found that they all tend to have an
initial increase in adrenaline compared with other children
when they enter the standard laboratory setting; however,
Gunnar (1994) found that their elevated adrenaline was
followed by elevated cortisol levels, presumably as a reac-
tion to threat, only for those inhibited children who before
entering the stimulating setting had first been left for a half
hour with an unresponsive adult. The same effect was also
found comparing inhibited children with secure versus inse-
cure attachments to their mothers (Nachmias et al., 1996).
However, sometimes inhibiting behavior could also be a part
of being responsive—taking the time to observe environmental
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8 Personality and Social Psychology Review XX(X)
cues rather than ignoring them—but these reasons for paus-
ing would not be as easily identified. The observed initial
response in inhibited children of adrenaline in the face of
novelty may well facilitate processing of information, only
leading to fearfulness when there is an actual threat or in
children where there is a lack of social support. In these stud-
ies, there is no true crossover interaction because there is no
indication of a “better than” outcome, in that inhibited chil-
dren did not have less initial adrenaline than others or behave
in a more uninhibited way than others when secure. (An
appropriate measure might have been their greater ability
under secure conditions to spot a specific toy with some sub-
tle desirable reward attached to it.) The point here is that an
important difference has been identified by the Kagan
research on inhibitedness, but if the underlying process was
nothing more than inhibition to avoid threat, there would be
no possibility of a “better than” outcome when the environ-
ment provides support for a child who is initially behavior-
ally inhibited in these settings.
Furthermore, recent neuroimaging studies (e.g., Bar-Haim
et al., 2009) have found that reward areas of the brain in
“inhibited” adolescents are more easily activated as well as
fear areas. That is, these individuals seem to be more respon-
sive to all situations, as if, again, their inhibited behavior is
best described as pausing to observe a new situation, and
depending on what they find, they are either more excited
than others by potential rewards or more threatened than oth-
ers by danger.
The question remains as to whether a trait defined as a
strong BIS is the same as SPS or the only important aspect of
SPS. A strong BIS does seem to include noticing subtle stim-
uli, perhaps motivated by stronger emotional reactivity, but
the answer lies in the future, as neuroscience sorts out better
the range of the proposed BIS system and whether its func-
tion of “pausing to check” to mediate conflicts between
approach and flee would extend to a general sensitivity to the
environment.
Continuing with the aspect we have called inhibition of
behavior, introversion can be seen as another, mostly social
form of it. Carl Jung (1921/1961) actually seemed to have
come the closest to describing a central role of sensitivity in
introversion, which he saw as a preference to observe and
reflect on an object, person, or situation, discovering its rela-
tion to one’s own past experiences and other subjective fac-
tors, versus the extraverted attitude of preferring to gain such
knowledge through direct, immediate contact. Indeed, his ini-
tial descriptor of this basic distinction was sensitiveness ver-
sus its lack, describing what amounts to a crossover interaction,
in that this sensitiveness as he described it interacts with expe-
rience to produce neuroticism, on one hand, and a certain
depth of character on the other (Jung, 1913/1961). Indeed, he
may have later preferred the term introversion because it was
a more neutral term for this sensitivity (E. Aron, 2004).
The problem is that separating an introverted attitude that
is due to depth of processing from one due to aversive social
experiences is not easily accomplished from observing an
outward behavior of doing less than others. The Five Factor
Model has based the definitions of introversion and extraver-
sion almost exclusively on what people can observe about
each other, and not being able to observe what introverts are
doing, a variety of lay theories result. For example, this type
of analysis of lay terms for generally observable behaviors
led Goldberg (1990) to label introversion as lethargy and
added the descriptors of aloofness, silence, modesty, pessi-
mism, and unfriendliness. Except for silence, these are all
inner states that could only represent guesses as to the reason
for inhibited behavior. Goldberg’s Surgency (extraversion),
however, is associated with easily observed behaviors: spirit,
talkativeness, sociability, spontaneity, boisterousness, adven-
ture, energy, conceit, vanity, indiscretion, and sensuality.
McRae and John (1993) provided similar adjectives: active,
assertive, energetic, enthusiastic, outgoing, and talkative,
now summarized as positive affect, and that introversion is
simply a lack of these.
In short, introversion does appear to overlap with some
inhibition of behavior in the service of sensitivity, but it seems
to be too broadly inclusive to understand how it does this.
Sensitivity to stimuli. Early research on children’s tempera-
ment traits identified individual differences in sensitivity
threshold. As already mentioned, Thomas and Chess (1977)
made it one of the nine basic traits distinguishing children. It,
together with other traits such as social withdrawal, makes
up the personality of what they called the slow-to-warm-up
child. Building on that work, Rothbart and Bates (2006)
described children’s temperament with reference to two
observable behaviors pointing to sensitivity: Perceptual
Sensitivity or awareness of subtle stimuli as part of Effortful
Control and Discomfort due to intensity of stimuli as part of
Negative Affectivity.
As said before, Evans and Rothbart (2007), in developing
the Adult Temperament Questionnaire, kept Effortful Control
and Negative Affectivity as scales with separate conceptual
and definitional specificity. Sensory discomfort was again
incorporated as a part of their scale of negative affect.
Orienting Sensitivity was elevated out of Effortful Control,
becoming a separate factor described as automatic attention
given to mostly subtle sensory events that are perceptual, affec-
tive, or associative, a very good description of responsivity/
sensitivity as described by SPS and the scale may be a good
measure of it. Because as far as we know the Adult
Temperament Questionnaire has not been used in crossover
interaction studies, it is not clear whether their temperament
trait of Negative Affect, and specifically that of Sensory
Discomfort, could be partly or totally the result of exposure
to a stressful environment, in childhood or recently. When
environmental contributions are accounted for, Sensory
Discomfort may correlate with Orienting Sensitivity as part
of the inevitable biological cost of a sensitive strategy (and
what would be expected in those with stronger emotional
reactivity when receiving stimuli that is too intense to ignore
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Aron et al. 9
or process). If Sensory Discomfort does not correlate with
Orienting Sensitivity after controlling for environmentally
caused negative affect, that would seem to support a distinc-
tion between the extreme sensory sensitivity that is due to
processing difficulties (e.g., Sensory Integration Disorders,
Autism) and that of a type of sensitivity related to more
effective processing of environmental stimuli.
Other interesting early descriptions of individuals with
sensitivity to subtle stimuli have called them “augmenters”
of stimulation (Petrie, 1967) or “reducers” (Buchsbaum,
Haier, & Johnson, 1983) of evoked potentials. Fine (1972)
argued for differences in sensitivity to stimuli as the best
explanation for field dependence–independence, finding
support for his view in the better performance of field inde-
pendent individuals on color and weight discrimination
tasks. Mehrabian (1976; Mehrabian & O’Reilly, 1980)
developed a measure of low stimulus screening that assumed
arousability to be an effect, not a cause, of having a greater
sensitivity to stimulation. That is, the research and measure
sought to demonstrate that there are persons who are more
sensitive than others to stimulation, and the best explanation
for that is a trait of sensitivity, not a trait of general arous-
ability or anxiety giving rise to sensitivity.
At one time, research on introversion came close to turning
that trait into one of general sensitivity: For two decades or
more, introversion was studied mainly as a physiological dif-
ference in sensitivity. (Indeed, the results of this vein of intro-
version research partly gave rise to our concept of SPS.)
Introverts were found to be more sensitive to low auditory fre-
quencies (Stelmack & Campbell, 1974; Stelmack & Michaud-
Achorn, 1985), to pain (e.g., Barnes, 1975; Haier, Robinson,
Braden, & Williams, 1984; Schalling, 1971), and to electrocuta-
neous (e.g., Edman, Schalling, & Rissler, 1979), olfactory (e.g.,
Herbener, Kagan, & Cohen, 1989), and visual thresholds (e.g.,
Siddle, Morrish, White, & Mangan, 1969). After numerous
such studies over a decade or more, Koelega’s (1992) meta-
analysis and Stelmack and Geen’s (1992) review of the litera-
ture argued that the hallmark of introversion is sensitivity. As
Stelmack wrote in 1997, “In my view, there is a substantial
body of evidence in research on the extraversion trait that con-
verges on one general effect, namely the greater sensitivity (or
reactivity) of introverts than extraverts to punctate, physical
stimulation” (p. 1239). He added, “What is striking about the
sensory reactivity effect is that it is evident for such a broad
range of psychological methods” (p. 1240). Interestingly, the
study of the relationship between introversion and sensitivity
to stimuli had largely ended by the turn of the millennium, per-
haps because the Five Factor Model has emphasized a different
perspective on the concept of introversion/extraversion.
Still, central as sensitivity to “puntate, physical” stimuli is
to a general sensitivity to the environment, it does not seem
to be identical with SPS. Indeed, without other aspects of
SPS, sensitivity to stimuli would seem to lack evolution-
ary advantage, as is seen in sensory integration impairments
and Autism Spectrum Disorders.
Depth of processing. Individual differences in depth of
processing have been the slowest to be recognized as a
potential personality or temperament trait, and then it was
almost by accident. Patterson and Newman (1993) set out to
study the problem of impulsive behavior by using rewards
and punishments (winning or losing money) for perfor-
mance on a task with feedback after each attempt. They
equated impulsivity with extraversion, and found that intro-
verts consistently used more time to reflect on feedback
about the nature of their mistakes before proceeding to the
next trial, and as a result were more successful. Patterson
and Newman suggested that taking time to reflect “promotes
semantic depth and differentiation by means of reflection”
(p. 724). As a result of their study, Patterson and Newman
reconceptualized “introversion” as reflectivity, perhaps an
equally good term for SPS, although the idea has not been
expanded and does not appear to include nonconscious,
automatic processing or the role of emotion.
Robinson, Moeller, and Fetterman (2010) approached
responsiveness to error feedback from the direction of neu-
roticism rather than introversion, noting that too much
responsiveness to negative feedback has been long associ-
ated with pathology, on one hand, but too little is associated
with the inability to recognize and regulate problematic
behaviors on the other hand. As predicted, they found that on
various cognitive tasks, the behavioral characteristic of
slowing down in response to error feedback was associated
with lower-than-average accuracy for individuals high in
neuroticism and to greater-than-average accuracy for those
low in neuroticism. That is, first, there is individual variation
in the degree to which individuals slow themselves down in
response to negative feedback, and the reasons for this differ.
In neurotics, it is probably due to anxiety and reduces accu-
racy. Nonneurotics who are highly sensitive may slow down
to notice and correct what they have been doing wrong and
this increases accuracy. All that is missing perhaps is the
appreciation of whatever unnamed trait is behind this
slower, more accurate style. They suggest that it is a lack
of emotional reactivity, obviously meaning a lack of neg-
ative emotional reactivity, but do not consider that a
greater-than-average positive feeling following being
accurate or a different type of negative affect (perhaps not
affecting self-esteem) might be assisting the nonneurotics
who slowed down.
These two studies that we suggest amount to a study of
depth of processing may come closest to capturing the phe-
nomenon of general sensitivity. However, what we hypothesize
to be the roots of these behaviors (e.g., emotional motivation
driving processing) are not explored in these studies and the
emphasis on conscious decision making misses a large por-
tion of how we argue SPS probably affects behavior.
Finally, we should note that in a quite different study that
may be related to depth of processing, Kjellgren, Lindahl,
and Norlander (2009a) found that high scorers on the HSP
Scale were more likely to report mystical experiences and
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10 Personality and Social Psychology Review XX(X)
altered state of consciousness when placed in sensory isola-
tion in flotation tanks for stress release.
Emotional/physiological reactivity. The final theorized aspect
of SPS that we will consider in our review of relevant person-
ality research is greater emotional reactivity, physiological
stress reactivity, or arousability. It is this behavior that has
been most often equated with SPS. However, we would argue
that emotional reactivity to the environment is only an aspect
of general sensitivity. It may be highly correlated with SPS,
but emotional reactivity can occur for other reasons and on its
own does not explain SPS as we conceptualize it. For exam-
ple, negative emotionality can be the result of Posttraumatic
Stress Disorder (PTSD) and have nothing to do with sensitiv-
ity. Although the reactions to PTSD are usually focused on
stimuli related to the trauma, it can generalize, especially
when the trauma is multiple, severe, or occurring in early
childhood, in which case we speak of those with negative life
histories and learning. The same is true of strong positive-
emotional reactivity on its own. Although conceptualized as a
part of SPS, it may be expressed more selectively by those
high in the trait. At least the stereotype of strong positive
emotion is of the nonsensitive, more impulsive extravert as
defined by the Five Factor Model (Goldberg, 1990).
As said before, stronger emotional reactivity might seem
to be an obstacle to an accurate response to the environment
as well as a source of unstable or labile self-esteem and
depression (Kernis, 2003). However, as Baumeister et al.
(2007) have argued, most emotion occurs after an event, sug-
gesting that its function is to promote a thorough processing
of information in order to have a more effective and rapid
response to similar situations in the future. In that case,
increased emotional reactivity as a trait would be an advan-
tage, in that it would motivate deeper processing and general
learning from or responsiveness to experience after it has
occurred. There is still the question, however, of being too
emotionally reactive prior to or during a response to the
environment. But there too emotional reactivity has its
advantages, provided it does not lead to overarousal. For
example, at the other extreme of arousal, patients with dam-
age to the amygdala and emotionally handicapped are
impaired in their ability to learn because they have no felt
reason to do so (Adophs, Tranel, & Buchanan, 2005).
The real culprit may be overarousal, as in the above study
by Robinson et al. (2010), in which those who were slow to
respond but accurate were viewed as using cognition rather
than emotion. In fact, perhaps they were simply staying
within an optimal level of emotional and general arousal for
the task. However, neurotics generally have a history of neg-
ative learning experiences that have led to an expectation of
feeling punished, shamed, or defeated if an error is made,
and this may have led to a level of arousal far beyond what
would be optimal for a cognitive task. Sensitive persons,
while emotionally reactive, have lifelong experience with
their stronger emotional reactions, and if raised in a supportive
environment would surely develop methods of affect regulation
such that their emotional reactions would remain at a level
that mainly enhances decision-making processes. The real
issue is accuracy, as emotional reactivity that evaluates a
situation correctly without conscious thought is the most
quick and efficient form of decision making. The emotional
reactions of neurotics, whether highly sensitive or not, are
more likely to be inaccurate, being based on a history of
dealing with threatening situations that will be overgeneral-
ized to present ones. It may be that the common assumption
that emotion interferes with cognition has been particularly
fueled by observing the uncontrolled emotional reactivity of
sensitive persons with negative histories, as it leads to over-
arousal when conscious decision making is required and
inaccurate decisions when faster responses are needed.
We would argue that a great deal of temperament, person-
ality, and clinical research has understandably focused on
negative affect as a heritable trait, thereby overlooking what
we suggest is the high likelihood that negative affect as a
personality variable is often the result of an interaction of
something like sensitivity (our hypothesized source of the
heritability) with a negative environment. The confusion is
understandable because the greatest need has been to under-
stand the sources of negative affect—chronic anxiety,
depression, and anger. In attempting to identify early in life
the contributing temperament traits, the presence or absence
of negative affect is one of the most easily observed indi-
vidual differences (Fox, Henderson, Rubin, Caldins, &
Schmidt, 2001), and the search for the genetic correlates of
neuroticism/negative affect has been reasonably successful
(Canli, 2006). Meanwhile, self-reports of stressful events, in
childhood in particular, are frequently disqualified as biased
by innate traits, and a longitudinal study measuring all types
of extreme stressors is difficult. Still, one of the strongest
arguments against genetically based neuroticism would seem
to be that evolution should have eliminated such a disadvan-
tageous trait. It seems more likely that when an individual’s
negative emotionality is genetically determined, again, the
genes are related to general emotional reactivity, so that neg-
ative emotionality is the result of emotional reactivity, as a
part of general responsivity, interacting with exposure to a
negative environment—that is, it is the negative side of a
crossover interaction, and the genes to date most associated
with neuroticism, 5-HTTLPR, do indeed yield crossover
interactions (Belsky & Pluess, 2009; Taylor et al., 2006).
This suggests that greater positive emotionality is being
promoted by the same genes and that this general emotional
reactivity, we would argue, is one important aspect of a
greater sensitivity to the environment. For example, espe-
cially in positive, enriched environments, the greater reac-
tivity of a sensitive child might increase sensitivity to the
environment by promoting curiosity and an excitement
about learning, or lead to deeper positive feelings for a
teacher, coach, or mentor that might in turn lead to greater
focus on subtle ways to improve responses compared with a
less emotional child.
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Aron et al. 11
As for general arousability, it has also been a long-
standing personality difference (e.g., Duffy, 1962; Eysenck,
1981; Strelau, 1983, 1994). Being more generally arousable
or autonomically reactive is then seen as an explanation for
other behaviors, such as being more cautious, introverted, or
shy, whereas those with low arousability would be extra-
verts, sensation seekers, reward dominant, and so forth.
However, evolutionary advantages were not emphasized nor
its relation to a general sensitivity. Ellis, Jackson, and Boyce
(2006), speaking of behavioral sensitivity to context, sug-
gested that it operates mainly through greater stress reactiv-
ity via the HPA, in response to being born into or sensitive
only at birth to those environments (very stressful or very
supportive) in which greater stress reactivity is an advantage.
It would seem HPA stress reactivity is very similar to the
SPS concept of emotional reactivity.
Research on SPS
Sensitivity as responsivity to the environment would seem to
mean that from birth those with the trait are noticing and
changing their behavior, not necessarily consciously of
course, according to their experiences. In that sense, from a
very young age they are more than others a product of their
environment, more affected by “nurture,” because of their
genetics, their “nature.” (This adds an interesting twist to the
personality-situation debate in personality theory, in that an
important trait might be how much persons change their
behavior from one situation to another, behavioral inconsis-
tency, which is easily studied in that people do vary in
behavior between Time 1 and Time 2 laboratory visits; see
Funder, 2006; Funder and Colvin, 1991. An interesting topic
for future research would be whether a large portion of the
variance on many self-report measures and in many labora-
tory experiments is contributed by highly sensitive partici-
pants.) This makes it difficult to identify them solely thorough
phenotypical behaviors, or even endophenotypes such as
biological reactivity, because environment can contribute to
these as well. Still, we can use a range of methods, as has
been done, for example, to study neuroticism, which as
noted, partially overlaps with sensitivity. At the outset, how-
ever, a questionnaire measure is valuable, in order both to
focus behavior observation, as well as enable experimental,
genetic, and neurophysiological methods such as functional
magnetic resonance imaging (fMRI) and evoked potential.
Development of the HSP Scale
The details of the development of the HSP Scale are avail-
able elsewhere (E. Aron & Aron, 1997), but the process of
its development was one of uncovering a possible trait of
general responsivity in humans, which we only gradually
realized as we read the animal personality literature as one
source of understanding our results. In the 1990s, the first
author became curious about the meaning of the common
personality descriptor “sensitive,” which is also used with-
out definition in clinical literature (e.g., referring to persons
more affected by trauma as “extremely bright, sensitive
people”; Kalsched, 1996, p. 11) with the implication that it
is innate. Curiosity led to interviews with persons self-
identified as highly sensitive (E. Aron & Aron, 1997, Study
1) through advertisements for persons who were especially
introverted or “easily overwhelmed by stimuli (such as noisy
places or evocative or shocking entertainment),” indicating
our initial thinking. From the many who responded, we
selected for an equal distribution of genders and across
decades of age and a variety of vocations (although 12 of the
39 were students). The first author interviewed each person
for 3 to 4 hr on a wide range of personal topics, from child-
hood history to current attitudes and life problems, and it
was these interviews that greatly expanded our conceptual-
ization. For example, we intended to ask more personal
questions at the end of the interviews, but persons across all
categories volunteered early that their particular form of
spirituality (e.g., “seeing God in everything,” long medita-
tion retreats, a religious vocation) was central to their lives.
Most had a strong connection to the arts and nature, and
unusual sympathy for the helpless (animals, “victims of
injustice,” etc.). Furthermore, in spite of the initial advertise-
ment, of the 35 interviewees who completed the Myers–
Briggs Type Indicator (Myers, 1962), 7 were extraverted.
When we created a 60-item questionnaire based on the
characteristics of those we had interviewed, it ranged far
beyond being easily overwhelmed by overstimulation, our
initial expectation. We narrowed the 60 to a 27-item scale
with alphas ranging from .64 to .75 over six samples (involv-
ing 604 undergraduate psychology students at different uni-
versities and a community sample of 301 obtained using
random digit dialing). Subsequent studies by others (e.g.,
Benham, 2006; Hofmann & Bitran, 2007; Meyer, Ajc henb renn er,
& Bowles, 2005; Meyer & Carver, 2000; Neal, Edelmann, &
Glachan, 2002) using the HSP Scale have found alphas of
.85 or higher. This is in spite of the items varying from hav-
ing a rich and complex inner life, and being conscientious
and deeply moved by the arts and music, to being more
shaken than others by changes in one’s life, having more
difficulty performing a task when being observed, startling
easily, and being more sensitive to pain, hunger, and caf-
feine. An item discarded from the original 60 due to a differ-
ence in response rate between genders, “would you be
willing to sit at the bedside of a dying stranger and comfort
them,” hardly reflected a simple wish to avoid overstimulating
situations or to be in ones with subtle stimuli. Yet all of these
varied items still correlated with items such as being both-
ered by loud noises or chaotic scenes. We concluded that
being easily overstimulated might be inevitable, given that
perceiving subtle cues and processing information so thor-
oughly has costs in terms of neurobiological energy (Korte
et al., 2005; Wolf et al., 2008), so that when a novel or intense
stimulus is unrelenting, the drive to process it ought to lead
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12 Personality and Social Psychology Review XX(X)
to depletion and eventually exhaustion as well as a motiva-
tion to avoid severe depletion from this cause in the future.
The breadth of the trait that we were exploring empiri-
cally led to our model of SPS as a more sensitive processing
of sensory data rather than simply more sensitive sensory
organs. However, we did not yet fully appreciate the role of
heightened emotional reactivity, even though it was present
in the interviews and in the items in the original 60 (e.g., do
you cry easily; fall in love hard). In the final scale, it was
only reflected in negative reactions to harsh or unrelenting
stimulation (e.g., Do you make it a point to avoid violent
movies and TV shows; . . . to arrange your life to avoid
upsetting or overwhelming situations). The original 60 also
included positive-emotion items that correlated well with the
overall scale (e.g., When you are feeling happy, is the feeling
sometimes really strong?). Unfortunately these were left out of
the final scale, like other well correlated items (e.g., being
bothered by heat, cold, films affecting you the next day), for the
sake of brevity. Inhibition of behavior was also not represented
in the scale, except in the only item about childhood, “Did par-
ents or teachers seem to see you as shy or sensitive?”
That we were studying a single trait in spite of its breadth
was also reflected in there being for each of the six samples
(Studies 2-7) a clear single-factor solution for this diverse set
of items, with a dramatic drop in eigenvalues (overall vari-
ance accounted for) from the first to second unrotated factor,
with the remaining factors as “scree” (low values tapering
off without any sudden drop). Thus, based on the standard
scree-test approach, the factor analyses also supported the
notion that the measure taps a single construct.
Interestingly, the distributions of scores on the HSP Scale
in all of our samples analyzed to date (total N > 2,000) also
mirror Kagan’s experience with the temperament construct
“inhibitedness” that he studies in young children. Using for-
mal taxometric methods, Woodward, Lenzenweger, Kagan,
Snidman, and Arcus (2000) found that the trait is distributed
more like an approximately dichotomous category variable
rather than as a continuum with a normal distribution. In
practice, this means that we usually find a break point some-
where in our sample distributions and the “curve” is flat-
tened, rather than most individuals grouped around a single
central mean. In our samples, typically between 10% and
35% fell into the highly sensitive category, depending on the
sample—for example, psychology classes tend to attract
more sensitive students than other classes. (For a discussion
of typological conceptions of personality, see Robins, John,
& Caspi, 1998; for a discussion of the related idea of global
traits, see Funder, 1991.)
Possible Facets of Sensitivity
as Subscales Within the HSP Scale
Some studies (Evans & Rothbart, 2008; Meyer et al., 2005;
Smolewska, McCafe, & Woody, 2006) have reported sub-
factors within the HSP Scale that possibly measure different
facets of sensitivity, or at least point to subfactors in the
scale. In the studies that have reported the eigenvalues for
the first several factors, results have all been very similar,
with a very large first eigenvalue (e.g., 26% of variance in
the 27 items accounted for by a single factor of around 12
items) and the second factor, substantially lower (e.g., 8% or
less), the rest dropping gradually to 0. However, in some
studies, the second and third were interpreted as indicating
that there may be three (Ease of Excitation [EOE], Aesthetic
Sensitivity [AES], and LSL; Smolewska et al., 2006) or
even four (Meyer et al., 2005) subfactors of the overall HSP
Scale. Still, as Smolewska et al. (2006) noted, “The positive
intercorrelations among these factors, however, are consis-
tent with a general, higher-order construct of SPS” (p. 1276).
Evans and Rothbart (2008), using a different method of
identifying the number of factors (a version of parallel analy-
sis), found support for both two- and three-factor solutions
(the latter similar in content to Smolewska et al., 2006) but
argued for a two-factor solution based on the match of the
content of these two factors to aspects of temperament mea-
sured in their Adult Temperament Questionnaire (Evans &
Rothbart, 2007). Specifically, Evans and Rothbart’s first
HSP-Scale subfactor corresponded to (and correlated with)
their Questionnaire’s “Sensory Discomfort” subscale, a trait
of negative affect. Their second HSP-Scale subfactor corre-
lated with their Questionnaire’s “Orienting Sensitivity” sub-
scale, which has items reflecting what we would call noticing
subtleties and depth of processing.
In two recently collected large data sets (A. Aron & Aron,
2010), when we forced two- and three-factor solutions, we
obtained quite similar patterns to those of Smolewska et al.
(2006) and Evans and Rothbart (2008). The first of the three
factors Smolewska et al. termed Ease of Excitation, but in
both theirs and our own first factor, the four strongest items
are about disliking being rushed (e.g., “Do you get rattled
when you have a lot to do in a short amount of time?” and
“Are you annoyed when people try to get you to do too many
things at once?”), suggesting the factor comes closer to a
negative version of preferring to observe and reflect before
acting. However, it also might be the result of there happen-
ing to be four items in the HSP Scale that asked almost the
same question, which for mathematical reasons could create
a strong factor without necessarily reflecting its unique
importance to the overall trait.
More generally, as noted, results of factor analyses have
been somewhat inconsistent. Indeed, Liss, Mailloux, and
Erchull’s (2008) confirmatory factor analysis found that
two- and three-factor solutions comparable with previous
studies had only marginal fits (e.g., respectively, root mean
square errors of approximation [RMSEAs] of .08 and .07;
comparative fit indexes [CFIs] of .78 and .81).
If there are different facets to an overall trait of sensitivity,
this would not be surprising. Indeed, we think there are at
least the four we described in the previous main section
(inhibition of behavior, sensitivity to stimuli, etc.). However,
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Aron et al. 13
the scale was not designed to tap facets having theoretical
construct validity, and we are cautious about drawing strong
conclusions from the factor analysis procedures because
results have been inconsistent across samples and methods
as to whether there are one or more factors. In addition, the
straightforward application of standard factor analysis meth-
ods to the HSP Scale is problematic for several technical rea-
sons: (a) As noted earlier, the distribution of HSP Scale scores
appears to be nonnormal (perhaps due to negative frequency,
Wolf et al., 2008, and possibly dichotomous in humans,
Kagan, 1994), so that factor analyses may be mostly based on
the 80% or so of the population who are probably not at all
highly sensitive; (b) the apparent two or more facets in some
studies may actually be artifacts of gender differences in pref-
erence for some of the items in Smoleska et al.’s (2006) AES
and Evan and Rothbart’s (2008) similar Orienting Sensitivity
factors (e.g., “enjoying fine scents, tastes, etc.”; “other peo-
ple’s moods affect you”); (c) there may be differential cor-
relations of items with negative affectivity (due to the robust
interaction with childhood experience described above and
the question of why a trait of negative affect by itself would
be supported by evolution); and (d) there is a likely differen-
tial susceptibility of items in the apparent facets to self-report
response biases (e.g., being conscientious and having a “rich,
complex inner life” in Smoleska et al.’s AES and Evan &
Rothbart’s Orienting Sensitivity seem especially vulnerable
to social desirability). Future research will help sort out this
issue, perhaps with factor analyses specifically addressing
some of these technical issues.
It should be noted that all of this research has relied solely
on classical test theory, so that a valuable focus of future
research would be an analysis based on item-response theory.
Relation of the HSP Scale
to Other Personality Measures
We have already discussed personality traits that could theo-
retically, in some cases, be aspects of a general sensitivity
and therefore not measured in a way that would adequately
capture that overall trait. If SPS indeed represents such an
overall trait, to the extent the HSP Scale assesses SPS, scores
would have to be at least partially distinct from measures of
personality traits based on other understandings of behaviors
that focus only on what are aspects of it such as the inhibi-
tion of social behaviors (introversion) and the reporting of
intense negative emotion (neuroticism).
Hence, we undertook (E. Aron & Aron, 1997) systematic
statistical comparisons of the sensitivity measure and several
measures of traditional personality traits of introversion and
neuroticism or negative affect. Regarding introversion, the
simple correlation of introversion with sensitivity varied
according to the introversion measure and the sample, from
.14 to .29. Using John, Donahue, and Kentle’s (1992) intro-
version measure from the Five Factor Model, the correlation
was .12 (not significant). Although some of the correlations
with introversion measures were significant, none were high.
Using four measures of neuroticism, the correlations ranged
from .41 to .62 (all significant), but far from perfect. Neur oticism
was the only one scale of the Five Factor Model that corre-
lated significantly or near significantly. (The multiple corre-
lation of all five scales with the HSP Scale was .54, p < .01,
mostly due to Extraversion and Neuroticism scales, so that
71% of the variance was not accounted for by the Five Factor
scales.)
Smolewska et al. (2006) also compared the HSP Scale
with the Five Factor Model using the Neuroticism-
Extraversion-Openness Five Factor Inventory (NEO-FFI)
and found a correlation (.45) with Neuroticism, similar to
what we had found, plus a .31 correlation with Openness
(which we had expected to find but did not in our sample).
They replicated our own finding of a lack of a significant
relationship with the Five Factor Model’s other three scales,
most notably extraversion–introversion. Perhaps this should
not be surprising, given that the Five Factor Model largely
describes introversion as lack of positive affect, while sensi-
tivity seems also to correlate with greater positive affect (see
discussion below).
We are particularly interested in the moderately strong
correlation of the HSP Scale with negative affect of various
kinds. Indeed, a number of studies, none of which unfortu-
nately investigated early childhood experiences that might
have created crossover interactions, have found correlations
of the HSP Scale or one of its facets with a variety of nega-
tive affect, stress, or subclinical negative variables, mostly
in college samples (Benham, 2006; Evers, Rasche, &
Schabracq, 2008; Hofmann & Bitran, 2007; Kemler, 2006;
Kjellgren, Lindahl, & Norlander, 2009b; Liss et al., 2008;
Meyer & Carver, 2000; Meyer et al., 2005; Neal et al., 2002).
Interestingly these are mainly with various forms of anxiety,
perhaps tapping a combination of depth of processing and
emotional reactivity. However, correlations with depression
have only been found through an interaction with negative
childhood environment.
We now view SPS as involving greater general emotional
reactivity, yet the original HSP Scale reflects mostly nega-
tive affect in response to overstimulation. Thus, we have
sought other ways to assess whether this reactivity is to both
negative- and positive-emotional stimuli and is present inde-
pendent of neuroticism. For example, after partialling out
neuroticism measures, the HSP scale still correlates with
general (not specifically negative) emotion questions—for
example, in one of our samples (E. Aron & Aron, 1997,
Study 6), with crying easily (.54 before partialling out neu-
roticism, .33 after), feeling love intensely (.31, .24), and
“when you are happy, is the feeling sometimes very strong?”
(.50, .30). This general emotional reactivity was further cor-
roborated by an experimental induction of positive and nega-
tive emotions (E. Aron et al., 2005, Study 4) already described
and has since been found using neuroimaging (Acevedo,
Aron, & Aron, 2010, described below). Hence, we think that
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14 Personality and Social Psychology Review XX(X)
emotional reactivity in the context of sensitivity can be viewed
as separate from other traits or conceptualizations of intense
emotional reactions.
Finally, as expected, the HSP Scale was correlated .62
with Mehrabian’s (1976) measure of low sensory screening,
which we consider one aspect of SPS.
Biologically Related
Research Using the HSP Scale
The SPS model (and the extent to which the construct is
assessed by the HSP Scale) suggests a clear link with neural
response and genotypes, endophenotypes, and new pheno-
typical behaviors, all reflecting a broader sensitivity.
Neural response. Two fMRI studies have suggested sensitiv-
ity to subtle stimuli through deeper levels of processing. In
the first (Jagiellowicz et al., 2011), 18 individuals who var-
ied in their scores on the HSP Scale carried out a change
detection task in the scanner, in which they rated each of a
series of landscape scenes for whether they were similar or
different from the previous one. The presentations were in
blocks, in which the variations (when there were variations)
were either gross or subtle. Those scoring higher on the HSP
Scale showed dramatically more activation in predicted
areas, compared with low HSP scorers, when doing subtle
(vs. easier) discrimination tasks. This greater activation dur-
ing subtle tasks appeared in a variety of regions, especially
those associated with visual attention and visual processing
(as opposed to simple visual perception). Some of these were
the right claustrum, left occipitotemporal, bilateral temporal,
and medial and posterior parietal regions as well as the right
cerebellum, all used for making connections between incom-
ing visual stimuli and information already in the brain. The
results held even after partialling out neuroticism and intro-
version, supporting the idea that it is specifically SPS that is
responsible for more elaborate processing. Overall it appears
that sensitive persons take more care when having to make
fine distinctions between stimuli.
Another result focusing on sensitivity to subtle cues was
found as part of a study (Hedden, Ketay, Aron, Markus, &
Gabrieli, 2008) designed to test neural response to a known
cultural difference in perception. In this study, 10 Americans
of European descent and 10 East Asians recently in the
United States underwent fMRI while doing simple visuospa-
tial tasks emphasizing judgments that were either context
independent (typically easier for Americans) or context depen-
dent (typically easier for Asians). Each group exhibited
greater activation for the culturally nonpreferred task in fron-
tal and parietal regions associated with greater effort in
attention and working memory.
However, the participants had also been administered
the HSP Scale, and in a subsequent analysis (A. Aron,
Ketay, et al., 2010), this overall effect of culture was found
to be dramatically and significantly moderated by individual
differences in SPS. Specifically, consistent with the theory
that highly sensitive individuals are more responsive to subtle
cues when making choices, they showed little difference as a
function of culture, whereas low sensitives showed strong
culture differences. That is, those scoring high on the HSP
Scale appeared to need less or no effort to overcome a cultur-
ally biased perception found in nonsensitive persons. This
interaction remained strong and clearly significant control-
ling for negative affectivity (neuroticism), social introver-
sion, gender, and individual differences in strength of cultural
identity, suggesting that a general sensitivity to subtle cues
overrides, in those with this trait, a more general tendency as
found in the rest of the population to struggle with these cues
when they oppose their own cultural bias.
A third fMRI study (Acevedo et al., 2010) found that the
HSP Scale correlated with a greater reaction to photos of
both happy and sad faces compared with neutral faces, and to
photos of a spouse’s happy or sad facial expressions com-
pared with strangers with the same expressions. The areas of
greater activation were not in areas associated with specific
or pure emotion (e.g., only with spouse sad, or mostly amyg-
dala activation) as much as they were in sensorimotor areas
and areas associated with empathy (e.g., ventral medial pre-
frontal cortex, precuneus; Lamm, Decety, & Singer, 2011).
Perhaps most striking was the significant activation across
all comparisons in areas of general awareness, notably the
insula. The insula seems to play so many roles, not only inte-
grating interoceptive stimuli (thirst, need for air, sensual
touch, exercise, temperature, wine-tasting in sommeliers,
music, perceptual decision making, and so much more) but
also integrating these with moment to moment emotional
states to create subjective feelings in such a way that Craig
(2009) has argued persuasively that the insula is “a potential
neural correlate of consciousness” (p. 59). If this is the case,
greater insula activation might well represent greater aware-
ness of or sensitivity to the inner and outer environment in
general—that is, SPS.
Genotype. Thus far, SPS has been tentatively associated with
the serotonin (Licht et al., 2011) and dopamine (C. Chen et al.,
2011) systems. Based on preliminary results from a Danish
community sample (Licht et al., 2011), high scores on the
HSP Scale are associated, not surprisingly, with the short(s),
low-expressing variant of the repeat length polymorphism
5-HTTLPR (serotonin transporter, 5-HTT, Linked Polymor-
phic Region). Specifically, the strongest association was
with the EOE facet, the first and largest. (Again, the correla-
tion with the 12-item first factor may simply be due to its
internal consistency, having four similar items.)
If this finding is replicated, it may clarify why findings of
a relationship between depression and the s-allele in the
human serotonin transporter gene have been so inconsistent.
If the s-allele serves a different function, one with advan-
tages in some circumstances, such as promoting a general
sensitivity, it would lead to depression only when there are
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Aron et al. 15
precipitating environmental factors as well, as found by
Taylor et al. (2006) and reviewed by Belsky and Pluess
(2009). In reviewing this interaction, authors have hypothe-
sized that the s-allele leads to stress reactivity (Caspi, Hariri,
Holmes, Uher, & Moffitt, 2010; Pluess, Belsky, Way, &
Taylor, 2010). However, again, we think that an alternative
likely explanation is a general sensitivity that is dependent
on stronger emotional response that motivate the depth of
processing necessary for this sensitivity to be effective in
promoting learning from past experiences.
Research on humans and other primates focusing on the
“bright side” of this s-allele, reviewed by Homberg and
Lesch (2011), definitely point to more than stress reactivity.
Specifically, findings for superior performance on an array
of cognitive tasks point to the s-allele being linked to greater
sensitivity to emotionally salient environmental cues. For
example, Roiser, Muller, Clark, and Sahakian (2007) com-
pared the effects of acute tryptophan depletion on ss and ll
genotype (there are actually three alleles: short, short-long,
and long-long) groups on tests of episodic memory and
attention. Contrary to predictions, the ss genotype group did
not respond more specifically to negative-emotion valenced
words; rather, both groups responded more to all emotionally
valenced words than to neutral words. In a study (Roiser,
Rogers, Cook, & Sahakian, 2006) of how the effects of the
drug ecstasy on serotonin depletion differs according to the
allele carried, surprising differences were found in the non-
ecstasy controls. On a gambling-based decision-making task,
ss volunteers outperformed ll participants, showing risk
aversion when there was a low probability of winning but
risk seeking when there was a high probability, plus substan-
tially longer reflection before making difficult choices. The
ss carriers also performed better on a delayed pattern recog-
nition task and a task requiring recognizing letters in mirrored
versus normal form. Similar “broadly superior performance”
(Jedema, et al., 2009, p. 7) on a variety of decision-making
tasks has been found in nonhuman primates carrying the s-allele
(rhesus macaques have only two alleles, short and long).
The s-allele is also associated in humans and nonhuman
primates with greater sensitivity to social stimuli (e.g.,
benefiting more from social support, Taylor et al., 2006)—
and is even associated with creative social dancing
(Bachner-Melman et al., 2005), which Homberg and Lesch
(2011) described as “mankind’s most ancient and universal
trait, reflecting a complex phenotype comprising courtship,
social communication, and spirituality” (p. 2). Interestingly,
Kim and colleagues (2010) found the same differential effect
of this gene on the perceptual bias due to culture in Koreans
and European Americans as was found for the HSP Scale look-
ing at brain activation during these tasks in those high and low
on the trait in the two cultures (A. Aron, Ketay, et al., 2010).
C. Chen et al. (2011), seeking to find something closer to
the strong associations between genes and traits predicted by
twin studies but not being found with single gene research,
considered essentially all the genes (98) with polymorphisms
that affect the dopamine system, and chose a trait, SPS,
“deeply rooted in the nervous system,” (p. 1). Employing a
multistep approach (ANOVA followed by multiple regres-
sion and permutation), they found a set of 10 loci on 7 genes
that predicted 15% of the variance of HSP Scale scores. An
additional 2% of the variance was contributed by stressful
life events (effects of earlier stressful life events and parental
warmth were absorbed by their covariance with recent life
events), a relatively small environmental contribution.
Dividing the genes by the subsystems of dopamine synthe-
sis, degradation/transport, receptor, and modulation, the last
two made the strongest contribution, but interestingly, only
interactions among subsystem genes made unique contribu-
tions to SPS.
Most of the newly identified foci have unknown function
according to C. Chen et al. (2011), but one, DRD2, was one
of the three polymorphisms associated with behavioral sus-
ceptibility (Belsky, 2005) in a meta-analysis by Bakermans-
Kranenburg and van Ijzendoorn (2011).
Summary and Future Directions
This article has reviewed SPS in the light of the model
within evolutionary biology of a negative-frequency depen-
dent trait of general responsivity or sensitivity in many or
most species, in that when a minority of individuals are
responsive, they gain advantages that are worth the biologi-
cal costs of this responsiveness, but if all individuals were
more responsive, there would be no advantage for any of
them. How this responsive strategy manifests in genotype or
phenotype would vary with the species. We have proposed
that in humans it has thus far been most directly and com-
prehensively explored as SPS using the empirically derived
27-item HSP Scale (although evidence from other measures
and approaches to related constructs—e.g., Boyce & Ellis,
2005; Evans & Rothbart, 2007—have pointed importantly
in the same direction). SPS is conceptualized as involving
deeper processing of stimuli across a very wide variety of
situations, supported by a greater response to both positive
and negative stimuli that motivates learning and thus leads
to more successful responses in future similar situations.
This depth of processing is mainly a cognitive (although not
necessarily conscious) activity, but also appears as a height-
ened response by the immune system (Boyce et al., 1995)
and to, for example, pain, caffeine, and hunger (E. Aron &
Aron, 1997). The HSP Scale may not capture all of these
facets, given how it was created empirically, but those who
score high on it also evidence fMRI results, for example,
that fit quite directly with the formal definition of SPS.
Again, all forms of sensitivity, whether to hunger, light-
ing, or others’ emotions serve the general evolutionary pur-
pose of noticing more aspects of Situation A to make better
choices in later Situation B, with the assumption that A is
enough like B to have been worth learning from. (This is
assumed to have particular benefits for social animals,
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16 Personality and Social Psychology Review XX(X)
including humans, by being able to gratify others by making
their needs more accessible, conform to others when that is
adaptive, or sense untrustworthiness in others.) However, in
some situations it is more beneficial to be less responsive—
for example, if Situation B, although appearing similar, has
little to do with Situation A. Furthermore, less sensitive indi-
viduals are able to avoid the biological costs of being sensi-
tive, which may include being easily overwhelmed when
stimuli are too intense, frequent, or novel.
SPS is similar to a number of previously studied human
traits based on more observable behaviors, such as inhibi-
tion or social introversion, that we have argued here may in
some cases be understood as facets of this underlying over-
all evolutionary trait of responsivity or sensitivity modeled
in humans as SPS. At least four such aspects captured by
previous personality research are (a) inhibited behavior,
either as a pausing to notice and respond accordingly or as a
previously planned nonresponsive behavior (avoiding what
is already known to be noxious, threatening, or lacking
worth); (b) sensitivity to subtle cues; (c) depth of processing
(whether conscious or automatic); and (d) heightened emo-
tional, biological, or stress reactivity, including being easily
distressed by too much stimuli. We have also emphasized
that in combination with a poor childhood environment, this
last aspect (greater emotional reactivity) can result in pre-
dominately negative affect or neuroticism, but otherwise the
emotional reactivity can be equally intense for positive reac-
tions, and sensitive persons with positive childhood experi-
ences (or participating in a mental health or educational
intervention) appear to have better outcomes on many
measures.
In addition, if SPS continues to be found to correlate with
the s-allele of the 5-HTTPLPR polymorphism, as suggested
by preliminary findings (Licht et al., 2011), the apparent
interaction with childhood environment noted earlier would
help explain the inconsistency in findings regarding the
s-allele being a predictor of depression, as well as being in
keeping with recent findings that there are advantages to
possessing this allele that are very similar to being especially
sensitive. An interesting question is whether and how much
the s-allele of the 5-HTTLPR polymorphism serves an evo-
lutionary strategy of responsivity that has succeeded because
the majority of the population carries one or two of the long
sequences (and what role the sl combination plays in such a
strategy). Research on genes associated with SPS will need
to look for other polymorphisms as well.
Directions for future research suggested by this review
also include finding other non-self-report methods, besides
genotyping, of identifying SPS. For example, it would be
helpful to identify endophenotypes such as predictable pat-
terns of brain activation in specific situations or differences
in brain morphology.
Furthermore, as our understanding of the apparent bio-
logical roots of and neural processes associated with SPS
become increasingly delineated, it may be valuable to refine
or elaborate the sturdy HSP Scale, which has served to pre-
dict so much of the SPS model, including the neuroscience
results. Indeed, it was not formulated taking into account the
potential effect of a negative childhood on the response to
some of its items, particularly those with negative wordings,
so that for now we strongly recommend in most cases par-
tialling out neuroticism when using the scale (as has been
done in a number of the recent studies cited here). The scale
also may not capture enough behaviors directly reflecting
depth of processing, which might be assessed by questions
such as being slow to make decisions or behaviors reflecting
heightened positive-emotional reactions. Hence, a revision
of the HSP Scale may be valuable. Future research might
also benefit from including measures that appear to tap
specific aspects of SPS, such as the Orienting Sensitivity
Scale of Evans and Rothbart’s (2007) Adult Temperament
Questionnaire. We also think that future work would benefit
from the inclusion of a measure of social desirability to
ascertain its role on various items or facets and from further
studies of the HSP Scale’s factorial structure, focusing espe-
cially on whether these factors do in fact indicate aspects of
SPS that may each serve the general evolutionary purpose
of greater responsivity but that have evolved in different
ways.
More generally, we think the ultimate determination of
whether a trait or consistent individual behavior difference
such as SPS truly serves the responsive strategy is whether
there are enough situations in which it consistently results in
“outsmarting” enough others, making more successful bets,
noticing another’s behavior in a way that leads to coopera-
tion, and so on. For example, does noticing and responding
to one’s own hunger (an item on the HSP Scale) relatively
early in a cycle of eating and resting encourage an individual
to search for food sooner than others, before a shortage, or
does being affected more by another’s mood (also an item)
lead to greater empathy and more successful mating and
child-rearing strategies in comparison with those who gener-
ally are less in tune with a mate’s or child’s moods?
Trait × environment interactions, because of their role in
demonstrating a general trait of sensitivity across environ-
ments, also would seem to deserve much more exploration in
the ways Belsky and Pluess (2009) have suggested. For
example, those studying trait × environment or gene × envi-
ronment interactions should be sure to check for crossover
interactions and include measures of potential positive out-
comes that might produce such a crossover. In terms of SPS,
some example directions might be studies of whether under
conditions of being given negative feedback, do sensitive
individuals perform less well due to their emotional reactiv-
ity than others, and conversely under conditions of positive
feedback do they perform better than others.
Indeed, knowing a person’s level of SPS would seem to
have potential application in a wide variety of areas of human
life (e.g., education, vocational choice, assignment of roles in
organizations, medical treatment, etc.), as well as affecting
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Aron et al. 17
other important personality variables, such as self-esteem.
(Interestingly, cultures appear to differ in whether a trait like
SPS is viewed as attractive or not; X. Chen, Rubin, & Sun,
1992. This might have a particularly profound effect on
the self-esteem of those high in SPS given that they are likely
to be especially careful readers of the sociometer; Leary
& Baumeister, 2000.) More generally, the research on sensi-
tivity in children, already begun by Boyce, Pluess, and oth-
ers, could have particular importance for society, in that it
may identify those children not only most susceptible to
damaging stress but also most likely to benefit from interven-
tions and to perform unusually well in the world with the
right start in life.
In addition, it would seem especially valuable to be able
to assess when a person deemed high in more well-known
traits such as neuroticism or shyness is in fact only or mainly
high in SPS. We would argue that a name for a trait repre-
sents a theory—implicit or explicit, folk or scientific—for
explaining an observable behavior. When observable behav-
ior is minimal, as when a person is quiet or not acting in a
situation, our theories are less likely to be correct. Especially
for the majority who are less sensitive, the theory will prob-
ably not be that the person is observing and planning a future
response. (The authors have several times witnessed quiet
children on the 1st day of preschool being addressed as shy
or afraid.) For example, Paulhus and Morgan (1997) gave an
intelligence test before placing students in a leaderless group
for seven weekly meetings, after each of which members
rated one another. At the outset, group members rated quiet
persons as less intelligent (in effect gave the trait of quietness
a name, less intelligent, based on a theory). By the end, the
ratings were more accurate—the less intelligent were rated
less intelligent, regardless of how much they talked. More
disturbing is that mental health professionals can make the
same mistake. A study by Gough and Thorne (1986) used
similar leaderless groups as part of a 3-day personality
assessment and found that quiet persons, especially men,
were rated by mental health professionals as significantly
lower on likeability, intelligence, and mental health. Yet
these clinicians’ assumptions about these men were utterly
wrong, given other assessments (SAT, grade point average
[GPA], Minnesota Multiphasic Personality Inventory [MMPI],
etc.) and the ratings provided by those who actually knew
them (their spouses or peers in their sorority/fraternity).
Misattributions by clinicians are not a small matter, given the
benefits our society might enjoy from a well-raised, well-
supported, confident minority who are especially alert to
opportunities and dangers in spheres of life affecting us all.
Any misattribution about the terms/theories for traits also sig-
nificantly affects personality research.
Finally, and most generally, we hope this article will serve
to encourage deeper thinking about the potential application
to humans of work derived from animal personality research
on a theory of general responsivity, and the potential of the
SPS trait (and the HSP Scale) as a human marker of this
responsivity. Even more generally (see also Nettle, 2006),
we hope this article will illustrate the potential for those of us
studying all aspects of human personality to refine our theo-
ries and terms by making use of the growing body of seemingly
highly relevant work by evolutionary biologists studying
personality differences within diverse species.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with
respect to the research, authorship, and/or publication of this
article.
Funding
The author(s) received no financial support for the research,
authorship, and/or publication of this article.
References
Acevedo, B., Aron, A., & Aron, E. (2010, August). Association of
sensory processing sensitivity when perceiving positive and
negative emotional states. Presented at American Psychologi-
cal Association, San Diego, CA.
Adophs, R., Tranel, D., & Buchanan, T. W. (2005). Amygdala dam-
age impairs emotional memory for gist but not details of com-
plex stimuli. Nature Neuroscience, 8, 512-518.
Amodio, M. D., Master, L. S., Yee, M. C., & Taylor, E. S. (2008).
Neurocognitive components of the behavioral inhibition and
activation systems: Implications for theories of self-regulation.
Psychophysiology, 45, 11-19.
Aron, A., & Aron, E. (2010, August). Are there positive and nega-
tive facets of high sensitivity? Presented at American Psycho-
logical Association, San Diego, CA.
Aron, A., Ketay, S., Hedden, T., Aron, E., Markus, H. R., &
Gabrieli, J. D. E. (2010). Temperament trait of sensory process-
ing sensitivity moderates cultural differences in neural response
[Special Issue on Cultural Neuroscience]. Social Cognitive and
Affective Neuroscience, 5, 219-226.
Aron, E. (2000). High sensitivity as one source of fearfulness and
shyness: Preliminary research and clinical implications. In
L. Schmidt & J. Schulkin (Eds.), Extreme fear, shyness, and
social phobia: Origins, biological mechanisms, and clinical
outcomes (pp. 251-272). New York, NY: Oxford University
Press.
Aron, E. (2004). Revisiting Jung’s concept of innate sensitiveness.
Journal of Analytical Psychology, 49, 337-367.
Aron, E., & Aron, A. (1997). Sensory-processing sensitivity and its
relation to introversion and emotionality. Journal of Personal-
ity and Social Psychology, 73, 345-368.
Aron, E., Aron, A., & Davies, K. M. (2005). Adult shyness: The
interaction of temperamental sensitivity and an adverse child-
hood environment. Personality and Social Psychology Bulletin,
31, 181-197.
Bachner-Melman, R., Dina, C., Zohar, A. H., Constantini, N., Lerer, E.,
Hoch, S., . . . Ebstein, R. P. (2005). AVPR1a and SLC6A4
gene polymorphisms are associated with creative dance perfor-
mance. PLoS Genetics, 1(3), e42.
at SUNY MAIN LIBRARY on February 16, 2012psr.sagepub.comDownloaded from
18 Personality and Social Psychology Review XX(X)
Bakermans-Kranenburg, M. J., & van Ijzendoorn, M. H. (2011).
Differential susceptibility to rearing environment depending on
dopamine-related genes: New evidence and a meta-analysis.
Development and Psychopathology, 23, 39-52.
Bar-Haim, Y., Fox, N. A., Benson, B., Guyer, A. E., Williams, A.,
Nelson, E. E., . . . Ernest, M. (2009). Neural correlates of reward
processing in adolescents with a history of inhibited tempera-
ment. Psychological Science, 20, 1009-1018.
Barnes, G. (1975). Extraversion and pain. British Journal of Social
and Clinical Psychology, 14, 303-308.
Baumeister, F. R., Vohs, D. K., DeWall, N. C., & Zhang, L. (2007).
How emotion shapes behavior: Feedback, anticipation, and
reflection, rather than direct causation. Personality and Social
Psychology Review, 11, 167-203.
Bell, I. R. (1992). Allergens, physical irritants, depression, and shy-
ness. Journal of Applied Developmental Psychology, 13, 125-133.
Belsky, J. (1997). Variation in susceptibility to rearing influences:
An evolutionary argument. Psychological Inquiry, 8, 182-186.
Belsky, J. (2005). Differential susceptibility to rearing influence:
An evolutionary hypothesis and some evidence. In B. Ellis &
D. Bjorklund (Eds.), Origins of the social mind: Evolutionary
psychology and child development (pp. 139-163). New York,
NY: Guilford.
Belsky, J., Bakermans-Kranenburg, M. J., & Van Ijzendoorn, M. H.
(2007). For better and for worse: Differential susceptibility to
environmental influences. Current Directions in Psychological
Science, 16, 300-304.
Belsky, J., & Pluess, M. (2009). Beyond diathesis stress: Differ-
ential susceptibility to environmental influences. Psychological
Bulletin, 135, 885-908.
Belsky, J., Steinberg, L., & Draper, P. (1991). Childhood experi-
ence, interpersonal development, and reproductive strategy: An
evolutionary theory of socialization. Child Development, 62,
647-670.
Benham, G. (2006). The highly sensitive person: Stress and physi-
cal symptom reports. Personality and Individual Differences,
40, 1433-1440.
Boyce, T. W., Chesney, M., Alkon, A., Tschann, M. J., Adams, S.,
Chesterman, B., . . . Wara, D. (1995). Psychobiologic reactivity
to stress and childhood respiratory illness: Results of two pro-
spective studies. Psychosomatic Medicine, 57, 411-422.
Boyce, W. T., & Ellis, B. J. (2005). Biological sensitivity to con-
text: I. An evolutionary-developmental theory of the origins
and functions of stress reactivity. Development and Psychopa-
thology, 17, 271-301.
Buchsbaum, M. A., Haier, R. J., & Johnson, J. (1983). Augment-
ing and reducing: Individual differences in evoked potentials.
In A. Gale & J. A. Wards (Eds.), Physiological correlates of
human behavior: Vol. 3. Individual differences and psychopa-
thology (pp. 117-138). London, England: Academic Press.
Bundy, A. C., Shia, S., Qi, L., & Miller, L. J. (2007). How does
sensory processing dysfunction affect play? American Journal
of Occupational Therapy, 61, 201-208.
Canli, T. (2006). Biology of personality and individual differences.
New York, NY: Guilford.
Carver, C. S., & White, T. L. (1994). Behavioral inhibition, behav-
ioral activation, and affective responses to impending reward
and punishment: The BIS/BAS scales. Journal of Personality
and Social Psychology, 67, 319-333.
Caspi, A., Hariri, A. R., Holmes, A., Uher, R., & Moffitt, T. E.
(2010). Genetic sensitivity to the environment: The case of
the serotonin transporter gene and its implications for studying
complex diseases and traits. American Journal of Psychiatry,
167, 509-527.
Chen, C., Chen, C., Moyzis, R., Stern, H., He, Q., Li, H., & Dong,
Q. (2011). Contributions of dopamine-related genes and envi-
ronmental factors to highly sensitive personality: A multi-step
neuronal system-level approach. PLoS ONE, 6, e21636.
Chen, X., Rubin, K., & Sun, Y. (1992). Social reputation and peer
relationships in Chinese and Canadian children: A cross-
cultural study. Child Development, 63, 1336-1343.
Coleman, K., & Wilson, D. S. (1998). Shyness and boldness in
pumpkinseed sunfish: Individual differences are context-spe-
cific. Animal Behaviour, 56, 927-936.
Craig, A. D. (2009). How do you feel—Now? The anterior insula
and human awareness. Nature Reviews Neuroscience, 10, 59-70.
Craik, F., & Lockhart, R. (1972). Levels of processing: A frame-
work for memory research. Journal of Verbal Learning and
Verbal Behavior, 11, 671-684.
Dingemanse, J. N., Kazem, A. J. N., Reale, D., & Wright, J. (2009).
Behavioural reaction norms: Animal personality meets individ-
ual plasticity. Trends in Ecology & Evolution, 21, 1-89.
Duffy, E. (1962). Activation and behavior. New York, NY: Wiley.
Edman, G., Schalling, D., & Rissler, A. (1979). Interaction effects
of extraversion and neuroticism on detection thresholds. Bio-
logical Psychology, 9, 41-47.
Ellis, B. J. (2004). Timing of pubertal maturation in girls: An inte-
grated life history approach. Psychological Bulletin, 130, 920-958.
Ellis, B. J., Essex, M. J., & Boyce, W. T. (2005). Biological sensi-
tivity to context: II. Empirical explorations of an evolutionary–
developmental theory. Development and Psychopathology, 17,
303-328.
Ellis, B. J., Jackson, J. J., & Boyce, W. T. (2006). The stress
response systems: Universality and adaptive individual differ-
ences. Developmental Review, 26, 175-212.
Ellis, B. J., Shirtcliff, E. A., Boyce, W. T., Deardorff, J., & Essex, M. J.
(2011). Quality of early family relationships and the timing and
tempo of puberty: Effects depend on biological sensitivity to
context. Development and Psychopathology, 23, 85-99.
Evans, D. E., & Rothbart, M. K. (2007). Development of a model
for adult temperament. Journal of Research in Personality, 73,
868-888.
Evans, D. E., & Rothbart, M. K. (2008). Temperamental sensitivity:
Two constructs or one? Personality and Individual Differences,
44, 108-118.
Evers, A., Rasche, J., & Schabracq, M. J. (2008). High sensory-
processing sensitivity at work. International Journal of Stress
Management, 15, 189-198.
Eysenck, H. J. (1981). A model for personality. New York, NY:
Springer-Verlag.
at SUNY MAIN LIBRARY on February 16, 2012psr.sagepub.comDownloaded from
Aron et al. 19
Fine, J. B. (1972). Field-dependent introvert and neuroticism:
Eysenck and Witkin united. Psychological Reports, 31,
939-956.
Fox, A. N., Henderson, A. H., Rubin, H. K., Caldins, D. S., &
Schmidt, A. L. (2001). Continuity and discontinuity of behav-
ioral inhibition and exuberance: Psychological and behavioral
influences across the first four years of life. Child Development,
72, 1-21.
Funder, D. C. (1991). Global traits: A neo-Allportian approach to
personality. Psychological Science, 2, 31-39.
Funder, D. C. (2006). Towards a resolution of the personality triad:
Persons, situations, and behaviors. Journal of Research in Per-
sonality, 40, 21-34.
Funder, D. C., & Colvin, C. R. (1991). Explorations in behavioral
consistency: Properties of persons, situations and behaviors.
Journal of Personality and Social Psychology, 52, 773-794.
Gannon, L., Banks, J., Shelton, D., & Luchetta, T. (1989). The
mediating effects of psychophysiological reactivity and recov-
ery on the relationship between environmental stress and ill-
ness. Journal of Psychosomatic Research, 33, 165-175.
Gilissen, R., Bakermans-Kranenburg, M. J., van Ijzendoorn, M. H.,
& Van der Veer, R. (2008). Parent-child relationship, tempera-
ment, and physiological reactions to fear-inducing film clips:
Further evidence for differential susceptibility. Journal of
Experimental Child Psychology, 99, 182-195.
Goldberg, L. R. (1990). An alternative description of personality:
The big-five factor structure. Journal of Personality and Social
Psychology, 59, 1217-1229.
Gosling, S. D. (2001). From mice to men: What can we learn about per-
sonality from animal research? Psychological Bulletin, 127, 45-86.
Gosling, S. D., & John, O. P. (1999). Personality dimensions in
nonhuman animals: A cross-species review. Current Directions
in Psychological Science, 8, 69-75.
Gough, H. G., & Thorne, A. (1986). Positive, negative, and bal-
anced shyness: Self-definitions and the reactions of others. In
W. H. Jones, J. M. Cheek, & S. R. Briggs (Eds.), Shyness: Per-
spectives on research and treatment (pp. 205-225). New York,
NY: Plenum.
Gray, J. A. (1981). A critique of Eysenck’s theory of personality.
In H. J. Eysenck (Ed.), A model for personality (pp. 246-276).
New York, NY: Springer.
Gray, J. A. (1985). Issues in the neuropsychology of anxiety. In
A. H. Ruma & J. D. Maser (Eds.), Anxiety and disorder (pp. 5-25).
Hillsdale, NJ: Erlbaum.
Groothuis, T. G. G., & Carere, C. (2005). Avian personalities: Char-
acterization and epigenesis. Neuroscience & Biobehavioral
Reviews, 29, 137-150.
Gunnar, M. R. (1994). Psychoendocrine studies of temperament
and stress in early childhood: Expanding current models. In
J. E. Bates & T. D. Wachs (Eds.), Temperament: Individual dif-
ferences at the interface of biology and behavior (pp. 175-198).
Washington, DC: American Psychological Association.
Haier, R. J., Robinson, D. L., Braden, W., & Williams, D. (1984).
Evoked potential augmenting-reducing and personality differ-
ences. Personality and Individual Differences, 5, 283-301.
Hedden, T., Ketay, S., Aron, A., Markus, H., & Gabrieli, J. D. E.
(2008). Cultural influences on neural substrates of attentional
control. Psychological Science, 19, 13-17.
Herbener, E. S., Kagan, J., & Cohen, M. (1989). Shyness and olfactory
threshold. Personality and Individual Differences, 10, 1159-1163.
Hessing, M. J. C., Hagelso, A. M., Schouten, W. G. P., Wiepkema, P. R.,
& Vanbeek, J. A. M. (1994). Individual behavioral and physi-
ological strategies in pigs. Physiology & Behavior, 55, 39-46.
Hofmann, S. G., & Bitran, S. (2007). Sensory-processing sensitivity
in social anxiety disorder: Relationship to harm avoidance and
diagnostic subtypes. Journal of Anxiety Disorders, 21, 944-954.
Homberg, R. J., & Lesch, K. P. (2011). Looking on the bright side
of Serotonin transporter gene variation. Biological Psychiatry,
69, 513-519.
Jagiellowicz, J., Xu, X., Aron, A., Aron, E., Cao, G., Feng, T., &
Weng, X. (2011). Sensory processing sensitivity and neural
responses to changes in visual scenes. Social Cognitive and
Affective Neuroscience, 6, 38-47.
Jedema, H. P., Gianaros, P. J., Greer, P. J., Kerr, D. D., Liu, S., Higley, J. D.,
. . . Bradberry, C. W. (2009). Cognitive impact of genetic varia-
tion of the serotonin transporter in primates is associated with
differences in brain morphology rather than serotonin neuro-
transmission. Molecular Psychiatry, 15, 512-522.
John, O. P., Donahue, E. M., & Kentle, R. L. (1992). The “big five”
inventory—Versions 4a and 54 (Tech. Rep.). Berkeley, CA:
Institute of Personality Assessment and Research.
Jung, C. (1961). The collected works of C. G. Jung: Freud and psy-
choanalysis. Vol. 4. Princeton, NJ: Princeton University Press.
(Original work published 1913)
Jung, C. (1961). The collected works of C. G. Jung: Psychological
types. Vol. 6. Princeton, NJ: Princeton University Press. (Origi-
nal work published 1921)
Kagan, J. (1989). The concept of behavioral inhibition to the unfa-
miliar. In J. S. Reznick (Ed.), Perspectives on behavioral inhi-
bition (pp. 1-24). Chicago, IL: University of Chicago Press.
Kagan, J. (1994). Galen’s prophecy: Temperament in human nature.
New York, NY: Basic Books.
Kagan, J., Reznick, S., & Snidman, N. (1988). Biological basis of
childhood shyness. Science, 240, 167-171.
Kagan, J., Snidman, N., Julia-Sellers, M., & Johnson, O. M. (1991).
Temperament and allergic symptoms. Psychosomatic Medi-
cine, 53, 332-340.
Kalsched, D. (1996). The inner world of trauma. New York, NY:
Routledge.
Kaplan, H., & Gangestad, S. (2005). Life history theory and
evolutionary psychology. In D. M. Buss (Ed.), The
handbook of evolutionary psychology (pp. 68-95). New
York, NY: Wiley.
Kemler, D. S. (2006). Sensitivity to sensoriprocessing, self-discrepancy,
and emotional reactivity of collegiate athletes. Perceptual and
Motor Skills, 102, 747-759.
Kernis, M. H. (2003). Target article: Towards a conceptualization of
optimal self-esteem. Psychological Inquiry, 14, 1-26.
Kim, H. S., Sherman, D. K., Taylor, S. E., Sasaki, J. Y., Chu,
T. Q., Ryu, C., . . . Xu, J. (2010). Culture, serotonin receptor
at SUNY MAIN LIBRARY on February 16, 2012psr.sagepub.comDownloaded from
20 Personality and Social Psychology Review XX(X)
polymorphism and locus of attention. Social Cognitive and
Affective Neuroscience, 5, 212-218.
Kjellgren, A., Lindahl, A., & Norlander, T. (2009a). Altered states of
consciousness and mystical experiences during sensory isolation in
flotation tank: Is the highly sensitive personality variable of impor-
tance? Imagination, Cognition and Personality, 29, 135-146.
Kjellgren, A., Lindahl, A., & Norlander, T. (2009b). Searching
for placebo effects: Do sensitive personality and breathing
instructions influence the experience of flotation-REST
(Restricted Environmental Stimulation Technique)? Individ-
ual Differences Research, 7, 212-221.
Kochanska, G. (1997). Multiple pathways to conscience for chil-
dren with different temperaments from toddlerhood to age 5.
Developmental Psychology, 33, 228-240.
Kochanska, G., Aksan, N., & Joy, M. E. (2007). Children’s fear-
fulness as a moderator of parenting in early socialization: Two
longitudinal studies. Developmental Psychology, 43, 222-237.
Kochanska, G., Casey, R. J., & Fukumoto, A. (1995). Toddlers’ sen-
sitivity to standard violations. Child Development, 66, 643-656.
Kochanska, G., Gross, J. N., Lin, M., & Nichols, K. E. (2002).
Guilt in young children: Development, determinants, and rela-
tions with a broader system of standards. Child Development,
73, 461-482.
Koelega, H. S. (1992). Extraversion and vigilance performance:
Thirty years of inconsistencies. Psychological Bulletin, 112,
239-258.
Koolhaas, J. M., Korte, S. M., De Boer, S. F., Van Der Vegt, B. J.,
Van Reenen, C. G., Hopster, H., . . . Blokhuis, H. J. (1999). Coping
styles in animals: Current status in behavior and stress-physiology.
Neuroscience & Biobehavioral Reviews, 23, 925-935.
Korte, S. M., Koolhaas, J. M., Wingfield, J. C., & McEwen, B. S.
(2005). The Darwinian concept of stress: Benefits of allostasis
and costs of allostatic load and the trade-offs in health and dis-
ease. Neuroscience & Biobehavioral Reviews, 29, 3-38.
Kristal, J. (2005). The temperament perspective. Baltimore, MD:
Brookes.
Lamm, C., Decety, J., & Singer, T. (2011). Meta-analytic evidence
for common and distinct neural networks associated with
directly experienced pain and empathy for pain. Neuroimage,
54, 2492-2502.
Leary, M. R., & Baumeister, R. F. (2000). The nature and func-
tion of self-esteem: Sociometer theory. In M. P. Zanna (Ed.),
Advances in experimental social psychology (Vol. 32, pp. 1-62).
San Diego, CA: Academic Press.
Licht, C., Mortensen, E. L., & Knudsen, G. M. (2011). Association
between sensory processing sensitivity and the serotonin trans-
porter polymorphism 5-HTTLPR short/short genotype. Biological
Psychiatry, 69, 152S-153S (Supplement for Society of Biological
Psychiatry Convention and Annual Meeting, abstract, 510).
Liss, M., Mailloux, J., & Erchull, M. J. (2008). The relationship
between sensory processing sensitivity, alexithymia, autism,
depression, and anxiety. Personality and Individual Differ-
ences, 45, 255-259.
Liss, M., Timmel, L., Baxley, K., & Killingsworth, P. (2005). Sen-
sory processing sensitivity and its relation to parental bonding,
anxiety, and depression. Personality and Individual Differ-
ences, 39, 1429-1439.
Lukaszewski, W. A., & Roney, R. J. (2011). The origins of extraver-
sion: Joint effects of facultative calibration and genetic polymor-
phism. Personality and Social Psychology Bulletin, 37, 409-421.
Lyons, D. M., Price, E. O., & Moberg, G. P. (1988). Individual dif-
ferences in temperament of domestic dairy goats: Constancy
and change. Animal Behavior, 36, 1323-1333.
McNamara, M. J., Stephens, A. P., Dall, R. S., & Houston I., A.
(2009). Evolution of trust and trustworthiness: Social aware-
ness favours personality differences. Proceedings of the Royal
Society B-Biological Sciences, 276, 605-613.
McNaughton, N., & Gray, J. A. (2000). Anxiolytic action on the
behavioural inhibition system implies multiple types of arousal
contribute to anxiety. Journal of Affective Disorders, 61, 161-176.
McRae, R. R., & John, O. P. (1993). An introduction to the five-factor
model and its applications. Journal of Personality, 60, 175-215.
Mehrabian, A. (1976). Manual for the Questionnaire Measure of
Stimulus Screening and Arousability. Los Angeles: UCLA.
Mehrabian, A., & O’Reilly, E. (1980). Analysis of personality mea-
sures in terms of basic dimensions of temperament. Journal of
Personality and Social Psychology, 38, 492-503.
Meyer, B., Ajchenbrenner, M., & Bowles, D. P. (2005). Sensory
sensitivity, attachment experiences, and rejection responses
among adults with borderline and avoidant features. Journal of
Personality Disorders, 19, 641-658.
Meyer, B., & Carver, C. S. (2000). Negative childhood accounts,
sensitivity, and pessimism: A study of avoidant personality dis-
order features in college students. Journal of Personality Dis-
orders, 14, 233-248.
Myers, I. B. (1962). Manual for the Myers-Briggs type indicator.
Princeton, NJ: Educational Testing Service.
Nachmias, M., Gunnar, M., Mangelsdorf, S., Parritz, R. H., & Buss, K.
(1996). Behavioral inhibition and stress reactivity: The mod-
erating role of attachment security. Child Development, 67,
508-522.
Neal, J. A., Edelmann, R. J., & Glachan, M. (2002). Behavioral
inhibition and symptom anxiety and depression: Is there a spe-
cific relationship with social phobia? British Journal of Clinical
Psychology, 41, 361-374.
Nettle, D. (2006). The evolution of personality variation in humans
and other animals. American Psychologist, 6, 622-631.
Patterson, C. M., & Newman, J. P. (1993). Reflectivity and learn-
ing from aversive events: Toward a psychological mechanism
for the syndromes of disinhibition. Psychological Review, 100,
716-736.
Paulhus, D. L., & Morgan, K. L. (1997). Perceptions of intelli-
gence in leaderless groups: The dynamic effects of shyness and
acquaintance. Journal of Personality and Social Psychology,
72, 581-91.
Petrie, A. (1967). Individuality in pain and suffering. Chicago, IL:
University of Chicago Press.
Pluess, M., & Belsky, J. (2009). Differential susceptibility to rear-
ing experience: The case of childcare. Journal of Child Psy-
chology and Psychiatry, 50, 396-404.
at SUNY MAIN LIBRARY on February 16, 2012psr.sagepub.comDownloaded from
Aron et al. 21
Pluess, M., Belsky, J., Way, B. M., & Taylor, S. E. (2010).
5-HTTLPR moderates effects of current life events on neuroti-
cism: Differential susceptibility to childhood influences. Prog-
ress in Neuro-psychopharmacology & Biological Psychiatry,
34, 1070-1074.
Robins, R. W., John, O. P., & Caspi, A. (1998). The typological approach
to studying personality. In R. B. Cairns & L. R. Bergman (Eds.),
Methods and models for studying the individual (pp. 135-160).
Thousand Oaks, CA: SAGE.
Robinson, D. M., Moeller, K. S., & Fetterman, K. A. (2010).
Neuroticism and responsiveness to error feedback: Adaptive
self-regulation versus affective reactivity. Journal of Personal-
ity, 78, 1469-1496.
Roiser, J. P., Muller, U., Clark, L., & Sahakian, B. J. (2007). The
effects of acute tryptophan depletion and serotonin transporter
polymorphism on emotional processing. International Journal
of Neuropsychopharmacology, 10, 449-461.
Roiser, J. P., Rogers, R. D., Cook, L. I., & Sahakian, B. J. (2006).
The effect of polymorphism at the serotonin transporter gene
on decision-making, memory and executive function in ecstasy
users and controls. Psychopharmacology, 188, 213-227.
Rothbart, M. K., & Bates, J. E. (2006). Temperament. In W. Damon,
R. Lerner, & N. Eisenberg (Eds.), Handbook of child psychol-
ogy: Vol. 3. Social, emotional, and personality development
(6th ed., pp. 99-166). New York, NY: Wiley.
Schalling, D. (1971). Tolerance for experimentally induced pain as
related to personality. Scandinavian Journal of Psychology, 12,
271-281.
Schjolden, J., & Winberg, S. (2007). Genetically determined varia-
tion in stress responsiveness in rainbow trout: Behavior and
neurobiology. Brain Behavior and Evolution, 70, 227-238.
Siddle, D. A. T., Morrish, R. B., White, K. D., & Mangan, G. L.
(1969). Relation of visual sensitivity to extraversion. Journal of
Experimental Research in Personality, 3, 264-267.
Sih, A., & Bell, A. M. (2008). Insights for behavioral ecology from
behavioral syndromes. Advances in the Study of Behavior, 38,
227-281.
Sih, A., Bell, A., & Johnson, J. C. (2004). Behavioral syndromes:
An integrative overview. Quarterly Review of Biology, 79,
241-277.
Smolewska, K. A., McCabe, S. B., & Woody, E. Z. (2006). A psy-
chometric evaluation of the highly sensitive person scale: The
components of sensory-processing sensitivity and their relation
to the BIS/BAS and big five. Personality and Individual Differ-
ences, 40, 1269-1279.
Stamps, J. A. (2007). Growth-mortality tradeoffs and “personality
traits” in animals. Ecology Letters, 10, 355-363.
Stamps, J., & Groothuis, G. G. T. (2010). The development of ani-
mal personality: Relevance, concepts and perspectives. Biolog-
ical Reviews, 85, 301-325.
Stelmack, R. M. (1997). Toward a paradigm in personality: Com-
ment on Eysenck’s view. Journal of Personality and Social
Psychology, 73, 1238-1241.
Stelmack, R. M., & Campbell, K. B. (1974). Extraversion and
auditory sensitivity to high and low frequency. Perceptual and
Motor Skills, 38, 875-879.
Stelmack, R. M., & Geen, R. G. (1992). The psychophysiology of
extraversion. In A. Gale & M. W. Eysenck (Eds.), Handbook of
individual differences: Biological perspectives (pp. 227-254).
Chichester, UK: Wiley.
Stelmack, R. M., & Michaud-Achorn, A. (1985). Extraversion,
attention, and auditory evoked response. Journal of Research in
Personality, 19, 416-428.
Strelau, J. (1983). Temperament, personality, activity. San Diego,
CA: Academic Press.
Strelau, J. (1994). The concepts of arousal and arousability as used
in temperament studies. In J. E. Bates & T. D. Wachs (Eds.),
Temperament: Individual differences at the interface of biology
and behavior (pp. 117-141). Washington: DC: American Psy-
chological Association.
Suomi, S. J. (1997). Early determinants of behaviour: Evidence
from primate studies. British Medical Bulletin, 53, 170-184.
Taylor, E. S., Way, M. B., Welch, T. W., Hilmert, J. C., Lehman, J. B.,
& Eisenberger, I. N. (2006). Early family environment, cur-
rent adversity, the serotonin transporter promoter polymor-
phism, and depressive symptomatology. Biological Reviews,
60, 671-676.
Thomas, A., & Chess, S. (1977). Temperament and development.
New York, NY: Brunner/Mazel.
Velderman, M., Bakermans-Kranenburg, M., Juffer, F., &
van Ijzendoorn, M. (2006). Effects of attachment-based inter-
ventions on maternal sensitivity and infant attachment: Dif-
ferential susceptibility of highly reactive infants. Journal of
Family Psychology, 20, 266-274.
Verbeek, M. E. M., Drent, P. J., & Wiepkema, P. R. (1994). Con-
sistent individual differences in early exploratory behavior of
male great tits. Animal Behavior, 48, 1113-1121.
Volbrecht, M. M., & Goldsmith, H. H. (2010). Early temperamental
and family predictors of shyness and anxiety. Developmental
Psychology, 46, 1192-1205.
Wilson, D. S., Coleman, K., Clark, A. B., & Biederman, L. (1993).
Shy–bold continuum in pumpkinseed sunfish (Lepomis gibbo-
sus): An ecological study of a psychological trait. Journal of
Comparative Psychology, 107, 250-260.
Wolf, M., Van Doorn, G. S., & Weissing, F. J. (2008). Evolution-
ary emergence of responsive and unresponsive personali-
ties. Proceedings of the National Academy of Sciences, 105,
15825-15830.
Wolf, M., Van Doorn, G. S., & Weissing, F. J (2011). On the coevo-
lution of social responsiveness and behavioural consistency.
Proceedings of the Royal Society B-Biological Sciences, 278,
440-448.
Woodward, S. A., Lenzenweber, M. F., Kagan, J., Snidman, N., &
Arcus, D. (2000). Taxonic structure of infant reactivity: Evi-
dence from a taxometric perspective. Psychological Science,
11, 296-301.
Zuckerman, M. (1994). Impulsive unsocialized sensation seek-
ing: The biological foundations of a basic dimension of per-
sonality. In J. E. Bates & T. D. Wachs (Eds.), Temperament:
Individual differences at the interface of biology and behavior
(pp. 219-255). Washington, DC: American Psychological
Association.
at SUNY MAIN LIBRARY on February 16, 2012psr.sagepub.comDownloaded from
... High sensitivity is a term that refers to sensory processing sensitivity, a genetically determined disposition that involves deeper cognitive processing of stimuli and higher emotional reactivity (Aron et al., 2012). This trait affects approximately 15-20% of the population across approximately 100 different species (Aron et al., 2012;Aron, 2017a). ...
... High sensitivity is a term that refers to sensory processing sensitivity, a genetically determined disposition that involves deeper cognitive processing of stimuli and higher emotional reactivity (Aron et al., 2012). This trait affects approximately 15-20% of the population across approximately 100 different species (Aron et al., 2012;Aron, 2017a). ...
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... These factors were therefore selected for model conceptualization, highlighting their strong association with CS. Low sensory threshold is a concept that can be associated with sensory processing sensitivity and represents a temperamental trait associated with greater responsivity to environmental and social stimuli (Aron et al., 2012). Highly sensitive women appear to be more reactive to both positive and negative stimuli and may be predisposed to greater CS activation, especially in cases of CH (Acevedo et al., 2014;Midenfjord et al., 2021). ...
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... Research suggests that approximately 15%-20% of the population are highly sensitive individuals. [14] In our research, SPS is perceived as an innate trait associated with heightened sensitivity and responsiveness to environmental and social stimuli [4,5]. This perspective underscores the complex nature of SPS and its significant effects on personal experiences and interactions with the world. ...
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... As the SPS has been consistently described in the literature as a plasticity mechanism, representing an evolutioninfluenced survival strategy (Aron et al., 2012), the pattern of findings may suggest that parental SPS influences may (Pluess et al., 2023;Weyn et al., 2022), their psychometric properties in the Greek-Cypriot community have not yet been explored. Therefore, the results of the present study it is necessary to be interpreted with caution. ...
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... To view a copy of this licence, visit http://creativecommons. org/licenses/by/4.0/. as their own [55]. Thus, they may identify with the adolescent's thoughts, emotions, and distress, which might, on the one hand, increase their own stress, while, on the other hand, their avoidant orientation and disapproving negative emotions might drive them to misinterpret their adolescent child. ...
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Investigations of the link between personality and depression provide a path to identifying at-risk individuals and developing tailored treatment. Sensory processing sensitivity, reflecting individual differences in processing of internal and external stimuli, has been found to predict depression severity. Based on a diathesis-stress model, the present study examines whether this association is moderated by adverse childhood experiences. An online survey containing standardized measures of adverse childhood experiences, sensory processing sensitivity, and depression severity, was administered to 558 college students. The sample was predominantly Hispanic (92%) and female (70%) with a mean age of 20.2 years. In support of the diathesis-stress model, sensory processing sensitivity was found to be significantly correlated with depression and this relationship was shown to be stronger at higher levels of adverse childhood experiences. Our findings suggest that individuals with high SPS are at increased risk for depression, particularly if they were raised in adverse environments. Our findings add to the growing research on links between personality and depression. Future research should seek to identify modifiable factors that could serve as potential intervention targets and to examine the extent to which ACEs might moderate the efficacy of such treatment approaches.
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This research extends longitudinally findings on child temperament as a moderator of the impact of socialization on conscience development, reported previously for contemporaneous data at toddler age. Children's temperament and maternal socialization at Time 1 (n = 103, aged 2–3 years) were considered predictors of future conscience, assessed using new observational and narrative measures. The moderation model was supported for predicting conscience at Time 2 (n = 99, age 4), and, to a lesser extent, at Time 3 (n = 90, age 5). For children fearful as toddlers, maternal gentle discipline, presumably capitalizing on the optimal level of anxious arousal, promoted conscience at Time 2. For children fearless as toddlers, perhaps insufficiently aroused by gentle discipline, alternative socialization mechanisms, presumably capitalizing on mother–child positive orientation (secure attachment, maternal responsiveness), promoted conscience at Times 2 and 3. Developmental interplay of temperament and socialization in emerging morality is discussed.
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The shy–bold continuum is recognized as a fundamental axis of behavioral variation in humans, but 3 major issues have not been addressed. First, the taxonomic distribution of shyness and boldness is unknown. Second, the ecological consequences of shyness and boldness have not been studied in natural populations. Third, no one has tried to predict and test patterns of shyness and boldness that might result from natural selection. We show that a shy–bold continuum, which influences diet, predator risk, and parasite fauna, exists in juvenile pumpkinseed sunfish (Lepomis gibbosus). Individual differences are relatively stable in nature but seem to disappear when the fish are held in social and ecological isolation in the laboratory. Thus, phenotypic stability may not reflect innate tendencies to be shy or bold but rather environmental conditions that maintain differences between phenotypically plastic individuals.
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Gorenstein and Newman (1980) proposed that poorly modulated responding for reward is the common diathesis underlying disinhibited behavior in several traditionally distinct person categories: psychopathy, hysteria, early onset alcoholism, childhood hyperactivity, and nonpathological impulsivity (e.g., extraversion). The authors extend this proposal by theorizing a psychological mechanism that highlights relations among disinhibition, reflection, and failures to learn from aversive feedback. The hypothesized mechanism is presented as 4 generic stages of response modulation: the dominant response set, the reaction to an aversive event, the subsequent behavioral adaptation, and the immediate and long-term consequences of reflection, or the lack thereof. The mechanism has implications for disinhibited individuals' impulsivity and provides a point of departure to study factors responsible for similarities and differences among these syndromes.
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Book
H. J. Eysenck This book is not an introduction to personality research, it is not a textbook, and above all it is not a model of personality. The title, A Modelfor Personality, was chosen on purpose to indicate that we are here concerned with a discussion of how models in this field ought to be constructed, what their functions were, and whether such models or paradigms could with advantage be produced at this stage of development. One particular aspect of personality, extraversion­ introversion (E), has been chosen to exemplify the desiderata which emerge from such a discussion. It is not suggested that personality and E are synonymous - merely that this particular dimension is perhaps better known than any other, has had more experimental work done on it than any other and has acquired a better theoretical substructure, and more links with genetics and physiology, than any other. Hence it seems most likely to serve as an example of how a satisfactory model of personality might ultimately be constructed, i. e. by analogy with E. Other dimensions of personality, such as neuroticism-stability or psycho tic­ ism-superego functioning, are mentioned in the discussion, but only when they overlap or interrelate with E. The book uses E as an example to illustrate the way in which a model of personality can be constructed, but it is in no way a summary of all that is known about E.
Chapter
This chapter provides an overview of life history theory (LHT). LHT conceptualizes specific allocation tradeoffs in terms of three broad, fundamental trade-offs: the present-future reproduction trade-off, the quantity-quality of offspring trade-off, and the tradeoff between mating effort and parenting effort. The chapter then considers specific applications of LHT to an understanding of the human life course. The topics concerning human life histories are the evolution of large brains, development and childhood, and aging. The chapter argues for ways in which LHT can and should be infused into evolutionary psychology. Over the past 40 years, evolutionary biology has witnessed a tremendous explosion in understanding of adaptations, particularly as they relate to behavior. A key foundation of these developments is economic cost-benefit analysis of selection pressures. LHT is not a particular domain of cost-benefit analysis; rather, it is a broad, overarching perspective within which understanding of adaptation must ultimately be situated.