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Personality Differences and Development: Genetic and Environmental Contributions

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In the twenty-first century, behavioral genetic research has broadened our knowledge about the origins of personality differences and development. On average, genetic factors account for more than 50% of the variance in accurate measures of personality traits. However, heritability estimates of personality traits steadily decrease with age. Genetic factors represent the primary source of long-term continuity of individual differences in personality, but also account for change – particularly in younger ages. On the other hand, environmental factors represent the primary source of personality change in every period of life, but also contribute to the relatively high stability of personality differences throughout the adult life span.
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MS.25011
The Genetic and Environmental Contributions to Personality
Differences and Development
Christian Kandler & Wiebke Bleidorn
In: J. D. Wright (ed.), The International Encyclopedia of Social and Behavioral Sciences, 2nd
Edition. (pp. 884-890) Elsevier Science Ltd.
Keywords
Big Five personality traits
Genetic and environmental influences
Stability and change
Biological and social maturation
Heritability
Abstract
In 21st century, behavioral genetic research has broadened our knowledge about the origins
of personality differences and development. On average, genetic factors account for more
than 50% of the variance in accurate measures of personality traits. However, heritability
estimates of personality traits steadily decrease with age. Genetic factors represent the
primary source of long-term continuity of individual differences in personality but also
account for change particularly in younger ages. Environmental factors represent the
primary source of personality change in every period of life, but also contribute to the
relatively high stability of personality differences throughout the adult life span.
Contact information:
Christian Kandler; Department of Psychology and Sport Sciences, Bielefeld University, Universitätsstr.
25, D-33615 Bielefeld, Germany; E-mail: christian.kandler@unibielefeld.de
Wiebke Bleidorn; Department of Developmental Psychology, Tilburg University, PO Box 90153; 5000
LE Tilburg; E-mail: wiebkebleidorn@gmail.com
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Introduction
Behavioral genetic research on the nature and nurture of personality differences and
development has made important progress during the last decades. This review presents
major findings on the influences of genetic and environmental factors on individual
differences, stability, and change in personality traits. For that purpose, we first give a short
definition of personality traits. We then present an overview of findings from recent
behavioral genetic studies on individual differences in personality traits. Third, we review
findings from longitudinal behavioral genetic studies on personality development in different
periods of life. In addition, we illustrate how these findings can inform different theories on
the nature and the nurture of personality development. Finally, we outline implications and
provide an outlook on present trends in the fields of quantitative and molecular genetics.
Personality Traits
In this review, we focus on traits as basic characteristics for the description of personality
differences. Personality traits are commonly defined as relatively stable patterns of
thoughts, feelings, and actions in which one individual differs from others. That is,
personality traits are fairly stable over time and across situations but still open to change.
Personality traits primarily represent economic units of analysis of individual differences in
stylistic and regulatory aspects of cognitions, emotions, motivations, and behavior. They do
not include broad-sense individual differences, such as physical features (e.g., attractiveness)
or abilities (e.g., intelligence).
The Big Five trait taxonomy is the most influential conceptual model that captures
personality traits along five dimensions of individual differences (John et al., 2008). Although
the five dimensions have been labeled in many different ways, a common characterization
employs the following labels: (1) neuroticism vs. emotional stability or negative emotionality;
(2) extraversion vs. introversion or positive emotionality; (3) openness to experiences or
intellect; (4) agreeableness; and (5) conscientiousness or constraint. The Big Five trait
taxonomy appears to capture the trait landscape as portrayed in many different languages,
societies, and cultures (McCrae and Costa, 2008). It is useful to integrate various systems
and major inventories of personality description in terms of temperament and personality
traits in a common framework (John et al., 2008). Each of the five traits hierarchically
subsumes a set of more specific traits (e.g., anxiety, impulsiveness, gregariousness, activity,
altruism, straightforwardness, dutifulness, achievement striving, openness to feelings or
ideas). This hierarchical model is called five-factor model (FFM) of personality.
The Big Five (or FFM) traits predict several specific behaviors, such as tobacco
consumption as well as important life outcomes, such as occupational success, divorce or
even mortality (Roberts et al., 2007). Therefore, the Big Five traits are typically
conceptualized as core characteristics the essential (i.e., the genetically anchored) basis of
personality (McAdams and Pals, 2006; McCrae and Costa, 2008).
Genetic and Environmental Influences on Personality Differences
According to the theory that Big Five personality traits reflect genetically anchored core
characteristics of personality, several studies have found that individual differences in
personality traits are substantially genetically influenced (Johnson et al., 2008). Moreover,
the hierarchical structure of the five-factor model has a solid biological basis and may
represent a common heritage of the human species” (Yamagata et al., 2006, p. 987). In their
meta-analysis, Johnson et al. (2008) reported that genetic factors accounted for about 50%
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of the variance in primarily self-rated Big Five personality traits. The remaining variance was
primarily due to environmental influences that were not shared by individuals and family
members raised within the same family (see Figure 1).
Figure 1. Standardized estimates of genetic and environmental influences (in percent) on individual
differences in Big Five personality traits based on findings from the meta-analysis by Johnson et al.
(2008). Estimates of genetic influences include both additive and nonadditive genetic factors, whereas
environmental influences are disentangled into factors shared and not shared by family members raised
within the same family.
46%
5%
49%
Neuroticism
56%
4%
40%
Extraversion
45%
12%
43%
Openness
35%
16%
49%
Agreeableness
52%
10%
38%
Conscientiousness
Genetic influences
Shared environmental influences
Nonshared environmental influences
4
After correction for variance due to random error of measurement and rater-specific
perspectives (e.g., self-perspective or well-informed peers), estimates of heritability for
personality traits (i.e., estimates of the degree to which individual differences in traits are
due to genetic differences) are often considerably larger (Kandler et al., 2010b; Riemann and
Kandler, 2010). Genetics factors accounted for more than 50% of individual differences in
these more accurate personality trait scores (compare Figure 2a with 2b). In a similar vein,
the proportion of individual differences in personality traits that was stable over time
(Bleidorn et al., 2009) and across situations (Borkenau et al., 2006) showed larger genetic
influences that accounted for about two third of the variance in consistent trait scores (see
Figure 2c and 2d). Moreover, after correction for random and nonrandom error of
measurement as well as occasion-specific and short-term stable influences (< 7 years),
genetic factors accounted for nearly 100% of the variance in long-term stable (> 12 years)
personality trait scores (see Figure 2e), particularly in young adulthood (Kandler et al.,
2010a). These findings are in line with the conceptualization of Big Five personality traits as
genetically anchored core characteristics of personality.
Genetic and Environmental Influences on Personality Development
Although individual differences in the Big Five traits are fairly stable over the adult life span,
recent studies have found a reversely U-shaped pattern for the degree of stability of
individual differences (i.e., rank-order continuity) from young to old age (e.g., Lucas and
Donnellan, 2011). That is, the rank-order continuity tends to be relatively low in childhood
(4-year test-retest correlations < .60), but rises across adolescence and young adulthood
reaching a plateau between the ages 40 and 70 (4-year test-retest correlations range
between .60 and .80). Beyond age 70, the rank-order continuity appears to decay, again (4-
year test-retest correlations < .60). Moreover, the continuity declines as the time interval
between measurements of personality increases. Most longitudinal studies with at least four
times of measurement suggest a gradual decline in rank-order continuity (Fraley & Roberts,
2005). However, the rank-order continuity does not decline to zero but reaches a positive
asymptote of about .40 (Fraley and Roberts, 2005). These patterns of stability (or instability)
of individual differences in personality traits over time suggest (1) that personality can
change at every age throughout the life span, and (2) that the most pronounced changes
occur in young and old age. But what are the sources of these changes?
Genetic Set Points and Environmental Fluctuation
The classic genetic set-point theory that is also known as the dynamic equilibrium model
(see Ormel et al., 2012, for a review) attributes long-term rank-order continuity of
personality traits to individual differences in genetically driven immutable individual set
points. Environmental influences are assumed to represent situational or short-term stable
factors affecting reversible changes or fluctuations round these set points. That is, on the
long run, individuals’ personality traits will always regress to their enduring set points.
According to this theory, an enhanced frequency of environmental fluctuations can
be expected during early and late adulthood that can explain the reduced rank-order
continuity at these ages (see Figure 3). In fact, adolescents and young adults experience
more positive and negative life events than middle-aged people (Kandler et al., 2012). Life
events are linked to major changes in life circumstances and social roles (e.g., moves, several
graduations from school, apprenticeship, or university, start an own family). These changes
in life circumstances may be associated with reversible changes in personality traits. Life
events may change the daily routine of individuals and require new behavioral responses
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and individual adaptations. Older adults also report more changes in life circumstances (e.g.,
retirement, death and illness of close relatives or peers) than mid-adults (Plomin et al.,
1990). Yet, on the long run, personality scores of individuals should return back to their
dispositional set points accounting for the long-term rank-order continuity of personality
traits.
Figure 2. Standardized estimates of genetic and environmental influences (in percent) on individual
differences in personality traits averaged across the Big Five traits. Estimates are based on (a.) the
meta-analysis by Johnson et al. (2008) in which more than 90% of considered studies on adult
personality relied on self-reports, (b.) the multiple-rater twin study by Kandler et al. (2010b), (c.) the
longitudinal twin study by Bleidorn et al. (2009), (d.) the twin study of Person × Situation profiles by
Borkenau et al. (2006), and (e.) the longitudinal multiple-rater twin study by Kandler et al. (2010a).
47%
9%
44%
a. Johnson et al. (2008)
63%
37%
b. Kandler et al. (2010b)
66%
34%
c. Bleidorn et al. (2009)
67%
33%
d. Borkenau et al. (2006)
92%
8%
e. Kandler et al. (2010a)
Genetic influences
Shared environmental influences
Nonshared environmental influences
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Genetic Set Points and Environmental Fluctuation
The classic genetic set-point theory that is also known as the dynamic equilibrium model
(see Ormel et al., 2012, for a review) attributes long-term rank-order continuity of
personality traits to individual differences in genetically driven immutable individual set
points. Environmental influences are assumed to represent situational or short-term stable
factors affecting reversible changes or fluctuations round these set points. That is, on the
long run, individuals’ personality traits will always regress to their enduring set points.
According to this theory, an enhanced frequency of environmental fluctuations can
be expected during early and late adulthood that can explain the reduced rank-order
continuity at these ages (see Figure 3). In fact, adolescents and young adults experience
more positive and negative life events than middle-aged people (Kandler et al., 2012). Life
events are linked to major changes in life circumstances and social roles (e.g., moves, several
graduations from school, apprenticeship, or university, start an own family). These changes
in life circumstances may be associated with reversible changes in personality traits. Life
events may change the daily routine of individuals and require new behavioral responses
and individual adaptations. Older adults also report more changes in life circumstances (e.g.,
retirement, death and illness of close relatives or peers) than mid-adults (Plomin et al.,
1990). Yet, on the long run, personality scores of individuals should return back to their
dispositional set points accounting for the long-term rank-order continuity of personality
traits.
The classic theory of genetically driven immutable set points and environmental
fluctuation, however, cannot explain the steady decline in rank-order continuity over time
(Fraley and Roberts, 2005). In addition, this theory cannot explain systematic mean-level age
trends, that is, increases in agreeableness and conscientiousness or decreases in neuroticism
from adolescence to middle adulthood (Roberts et al., 2006). These findings contradict the
assumption of genetically driven set points that are immutable.
Genetic Continuity and Biological Maturation
Similar to the dynamic equilibrium model, McCrae and Costa (2008) attributed continuity in
personality traits to genetic sources. In their five-factor theory (FFT), they explain age trends
and rank-order change in FFM personality traits by genetically predisposed maturation
processes, in particular in the first decades of life. They do not negate environmentally
driven long-term changes, but they claim that maturation is largely independent of
environmental influences and that external factors become only manifest through biological
changes (see Figure 4). This theory can explain long-term mean-level changes as well as
changes in individual ranks.
In line with the five-factor theory, mean-level trends are largely similar across several
nations and cultures (McCrae et al., 2005). Also in line with the hypothesis of genetically
driven maturation, several longitudinal behavioral genetic studies on personality stability and
change in childhood, adolescence, and young adulthood have found a non-perfect genetic
continuity of personality differences (e.g., De Fruyt et al., 2004; Gillespie et al., 2004;
Hopwood et al., 2011; Spengler et al., 2012). This reflects genetically mediated changes in
individual ranks during this period of life (Kandler, 2012).
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Figure 3. This figure illustrates how the genetic set-point theory can explain that rank-order
continuity is lower in younger and older ages. Dotted lines represent the immutable set points of
three persons. Continuous lines reflect environmental fluctuations round these individual set points
which are more pronounced in younger and older ages.
Even though rank-order continuity in personality traits are mainly due to genetic sources,
environmental change, however, can also become manifest in long-term rank-order
continuity (≥ 10 years), in particular in middle adulthood (Bleidorn et al., 2009; Kandler et al.,
2010a). Environmental influences may accumulate throughout the life span leading to a
decline in heritability of personality traits with age (Kandler, 2012). A recent study also found
systematic cross-cultural differences in age trends in personality traits that can be linked to
the normative duration of education in the respective countries (Bleidorn et al., 2013). These
findings contradict the assumption of internally driven maturation of personality traits that
are largely independent of environmental influences.
Genetic and Environmental Continuity and Social Maturation
In contrast to FFT, many other theories stress the importance of environmental influences
on personality stability and change over the life span. For example, sociogenomic theory of
personality by Roberts and Jackson (2008) states that the observed continuity of individual
differences in personality can be explained by both genetic as well as environmental factors,
in particular social factors (e.g., continuity in social roles). This theory explains personality
change by environmental processes (e.g., changes in individual life conditions due to major
life transitions or changes in social roles) (see Figure 5).
Individual values
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Figure 4. This figure illustrates the major claims of the theory by McCrae and Costa (2008) regarding
the sources of continuity and change in personality traits. Genetic and biological factors contribute to
both continuity and change, whereas environmental factors can only unfold their influences through
biological changes.
Consistent with this perspective is the fact that major familial and occupational roles are
largely stable in middle adulthood. This accounts for the relatively high stability of
personality differences in this period of life. Furthermore, there are normative biosocial
transitions (e.g., puberty, leaving parental home, graduation from school, apprenticeship, or
university, starting a family, menopause, retirement) in each period of life and there may
occur life events with positive (e.g., birth of own child, raise of salary) and negative
consequences (e.g., accident, layoff) that may lead to changes in social roles, individual living
conditions, and new persistent demands on the individual that can explain enduring
personality change in every age (Roberts et al., 2008). The increase of personality stability
from childhood to adulthood may reflect a process of social maturation the development
of, committing to, and maintaining an identity that is functional and integrated in its social
community, society, and culture. In line with this position is the finding that the increase of
rank-order continuity of personality traits in middle adulthood is, in fact, attributable to
stabilizing environmental influences (Kandler et al., 2010a).
Social maturation alone, however, cannot explain the consistent findings of non-
perfect genetic continuity of personality differences from childhood to young adulthood
(Kandler, 2012). But instable or changing genetic influences to personality differences in
younger ages are explainable by the hypothesis of genetically driven maturation.
Genetic/Biological Factors
Environmental Factors
Continuity
Change
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Figure 5. This figure illustrates the major claims of the socio-genomic theory by Roberts and Jackson
(2008) regarding the sources of continuity and change in personality traits. Both genetic and
environmental factors contribute to personality continuity, whereas environmental factors
contribute to personality change both directly and mediated by biological changes.
An Integrative Perspective on Genetic and Environmental Development
The above mentioned theoretical models provide different perspectives on the sources of
personality differences, stability, and change. Whereas the dynamic equilibrium model and
FFT attribute long-term rank-order continuity in personality traits to genetically anchored
immutable set points, the sociogenomic model allows for experience-dependent long-term
personality stability. Whereas FFT mainly attributes personality change to genetic and
biological sources, the sociogenomic model primarily explains change by environmental
sources that become manifest in individual states or social roles and have to be stable or
reoccur for a while before they will be permanently anchored in personality traits.
As discussed above, it seems as every single model cannot explain the entire range of
empirical findings. This calls for an integrative model that allows for genetic and
environmental continuity as well as genetic and environmental change as a function of age.
Such a model can be described in terms of the following five principles that are mainly
derived from the empirical findings described above.
(1) Genetic factors represent the primary source of long-term continuity of individual
differences in personality.
This principle is consistent with findings that suggest a larger genetic continuity compared to
environmental continuity across age (Kandler, 2012). Moreover, it explains the findings of
larger genetic contributions to long-term (≥ 10 years) rank-order continuity of personality
Genetic/Biological Factors
Environmental Factors
Continuity
Change
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traits (Bleidorn et al., 2009; Kandler et al., 2010a). Moreover, a stable genetic core may
account for the positive (non-zero) asymptote to which rank-order continuity declines as the
time interval between measurement occasions get longer (Fraley and Roberts, 2005).
(2) Environmental conditions and related personality-relevant life experiences are more
stable in middle adulthood than in younger and older periods of life.
This principle is in accord with the finding that environmental continuity of personality
differences is larger in middle adulthood than in other life phases (Kandler, 2012). The high
environmental continuity (e.g., in familial and working contexts) accounts for the relatively
high plateau of rank-order continuity of personality traits between the ages 40 and 70 (Lucas
& Donnellan, 2011).
(3) Genetic (or biological) maturation can account for personality change in childhood,
adolescence, and young adulthood.
This principle explains the non-perfect but increasing genetic continuity in the first decades
of life until perfect genetic continuity is reached in middle adulthood (Kandler, 2012).
Universally similar maturation processes in personality may account for similar age trends
across different cultures and societies (McCrae et al., 2005).
(4) Life experiences (social maturation) can affect personality change in every period of life.
According to this principle, environmental influences are the primary source of change in
personality traits (Bleidorn et al., 2009). Moreover, environmental contributions (compared
to genetic contributions) to individual differences in personality traits increase across the life
span leading to a decline of heritability across age (Kandler, 2012). Processes of identity
formation that leads to a socially functional and well-adapted personality (i.e., social
maturity) may play a major role in adolescents and young adulthood accounting for the
increase in environmental continuity across adolescence, young, and middle adulthood
(Hopwood et al., 2011; Kandler et al., 2010a). It lies in the human nature to use its natural
potentials of learning, self-reflection, and personal enhancement to develop a functional
identity that is socially accepted and culturally integrated. Thus, personality maturation may
also depend on social and cultural influences (Bleidorn et al., 2013).
(5) Complex interplays between genetic and environmental factors contribute to personality
development during all phases in life.
Emerging adults are typically more motivated to choose or change environments that match
their genetic predispositions (i.e., niche picking). This may explain the larger heritability
estimates for personality traits within the first decades of life (Kandler, 2012). To the
contrary, processes of personality adaptation to maintain the created niches and the
functional identity are more important in middle and old adulthood. This can account for the
shift from the importance of genetic influences to environmental influences on personality
differences across adulthood (Kandler, 2012). Most of the reported behavioral genetic
findings have relied on twin data. In twin studies, however, interactions between genetic
factors and environmental factors are often not taken into account in the analyses of twin
similarity (Eaton et al., 2012). If interactions between genetic factors and environmental
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factors shared by twins reared together are present but not taken into account, these effects
would act like genetic influences. Given this interaction plays a major role in the first
decades of life when twins share their parental home and other common experiences (e.g.,
school or cliques), then the contribution of genetic influences to individual differences in
personality should be larger in younger ages. This, again, is in line with larger heritability
estimates for personality traits within the first decades of life. The other way round, if
interactions between genetic factors and environmental factors not shared by twins reared
together are present but not taken into account, these effects would be confounded with
estimates of nonshared environmental influences. Given this interaction plays a major role in
adulthood when twins have left their common parental home and cut their own paths, then
heritability should decrease in this period of life. This is in accord to the increasing
importance of environmental influences on personality differences across adulthood.
In summary, a model that integrates ostensibly contradicting claims can account for
the whole empirical findings. Personality development is a very complex affair. We can only
understand the complete picture, if we focus on both genetic and environmental sources as
well as the complex interplay between them.
Outlook on Present and Future Trends
Future Studies on Personality Differences and Development
Many of the findings we referred to above refer to only a few broad personality traits,
primarily neuroticism and extraversion. It remains an open question whether we can find the
same patterns and sources of continuity and change across the life span for other
personality traits, such as openness, agreeableness, conscientiousness, or more specific
personality facets.
With respect to broad-sense personality, there are interesting differences between
personality traits and abilities regarding the relative contributions of genetic and
environmental influences to individual differences over the life span. Whereas heritability
increases for abilities across age (Briley and Tucker-Drop, 2013), heritability of traits appears
to decrease in adulthood. Maybe, there are different processes involved in the development
of traits and abilities (Kandler et al., 2013). This needs to be addressed directly in future
studies.
A related question is which patterns of genetic and environmental continuity and
change we can find for other personality characteristics that are associated to some degree
with the Big Five traits and cognitive abilities, but represent other attributes with more
motivational content (e.g., self-related and social attitudes, values, motives, needs, and
interests). Future studies should invest more efforts to study the nature and nurture in the
development of these characteristics.
Bridging of Quantitative and Molecular Genetic Studies
There is still a large discrepancy between the quantitatively genetic findings of large
heritability estimates for personality traits and the inconsistent and less replicable findings
of very small effects of gene variants accounting for personality differences from the field of
molecular genetics. This is often called the missing heritability problem. How can we
overcome this large discrepancy? In the following, we provide several hypotheses that need
to be investigated by future research.
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First, developmental behavioral genetic studies suggest that some genetic factors
may emerge in specific ages and that heritability appears to vary across age. Therefore, age
differences have to be taken into account in molecular genetics’ association studies.
Second, most large genome-wide association scan (GWAS) studies on personality
differences rely on short and unreliable measures of personality traits. Since heritability
estimates increase with accuracy of measurement (Kandler et al., 2010b; Riemann &
Kandler, 2010; Kandler et al., 2013), molecular genetic studies should be able use more
reliable and valid measures of personality traits. For sure, this may be useful to catch more
robust gene effects on the level of candidate genes or even single nucleotide polymorphisms
(SNPs).
Third, personality traits may be affected by multiple gene variants with very small
and statistically insignificant effects. In line with this consideration, a recent study has found
that common SNPs that is, the additive combination of the smallest gene units that vary
among individuals can explain 12% of the variance in extraversion and 6% of the variance
in neuroticism (Vinkhuyzen et al., 2012).
Fourth, heritability estimates often stem from studies on within-generational
relatives (e.g., twins and other siblings). These estimates include variance due to the
nonadditive combination of gene variants that vary among individuals within gene loci (i.e.,
allelic dominance) or between gene loci (i.e., epistatic gene interactions). Since twin studies
have often found higher heritability estimates on the basis of twin similarity compared to
adoption or pedigree studies on personality similarity among other family relatives
(Vinkhuyzen et al., 2012), this speaks for epistatic gene interactions that are only shared by
monozygotic (genetically identical) twins. Epistatic interactions are hard to identify and its
effects are even harder to replicate. From these four points of view, the discrepancy
between quantitative and molecular genetics regarding the amount of genetic influences on
individual differences in personality is not surprising.
Manifestations of Environmental and Epigenetic Factors
Behavioral genetic research suggests that nurture is primarily individual-specific. That is,
environmental influences are primarily not shared by family members raised within the
same family. Effects of specific environmental variables (e.g., life events) are typically
relatively small, accounting for lower than 2% of individual differences in personality traits
(e.g., Kandler et al., 2012). This displays a parallelism to the missing heritability problem we
therefore call the missing environmentality problem.
As a parallelism to multiple gene variants with very small and statistically insignificant
effects, specific environmental variables alone may have negligible effects. In line with this
perspective aggregates of several environmental variables can account for about 13% of the
variance in individual attributes (Turkheimer and Waldron, 2000). In addition, as a
parallelism to the role of epistatic gene interactions, several environmental factors may
affect some but not all individuals and they may interact with other experiences.
Finally, twin studies on epigenetic effects indicate that epigenetic imprinting (e.g.,
DNA-methylation or histone-modification) can account for differences between monozygotic
twins’ gene expressions (see van Dongen et al., 2012, for a review). Not surprisingly,
epigenetic differences show a small heritability of lower than 10%. That is, epigenetic effects
primarily reflect individual-specific environmental influences. Epigenetic effects may
increase over the life span (epigenetic drift). This epigenetic drift can mirror the increase of
environmental contributions to the variance in personality traits across the life span on the
level of gene expression.
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Conclusions
Behavioral genetic research on personality has made enormous progress within the last
decade. We have learnt a lot about the genetic and environmental contributions to
personality differences, stability, and change. Genetics factors account for about 50% of the
variance in personality self-reports. However, heritability estimates are often considerably
larger for more accurate, cross-time stable, and cross-situations consistent measures of
personality traits. Genetic factors represent the primary source of long-term continuity of
individual differences in personality, whereas the stability of environmental factors increases
until middle adulthood. Environmental sources affect personality change in every period of
life, but genetic factors can also explain change in childhood, adolescence, and even in
young adulthood. Finally, heritability of personality traits steadily declines in adulthood that
is completely different to the well-known trend for cognitive abilities. These findings have
helped to integrate ostensibly contradicting theoretical models by formulating five principles
of the nature and the nurture in personality development that fit the empirical results. There
are still many open questions that need to be answered by future research. Two broad areas
of for future research are the missing heritability and environmentality problem that need to
be addressed by future behavioral genetic studies.
References
Bleidorn, W., Kandler, C., Riemann, R., Angleitner, A., Spinath, F. M., 2009. Patterns and
sources of adult personality development: Growth curve analyses of the NEO-PI-R scales
in a longitudinal twin study. Journal of Personality and Social Psychology, 97, 142–155.
Bleidorn, W., Klimstra, T. A., Denissen, J. J. A., Rentfrow, P. J., Potter, J., Gosling, S. D., 2013.
Personality maturation around the world: A cross-cultural examination of social-
investment theory. Psychological Science, published online. DOI:
10.1177/0956797613498396
Borkenau, P., Riemann, R., Spinath, F. M., Angleitner, A., 2006. Genetic and Environmental
Influences on Person × Situation Profiles. Journal of Personality, 74, 1451-1479.
Briley, D. A., Tucker-Drob, E. M., 2013. Explaining the increasing heritability of cognitive
ability across development: A meta-analysis of longitudinal twin and adoption studies.
Psychological Science, 24, 1704-1713.
De Fruyt, F., Bartels, M., Van Leeuwen, K. G., De Clercq, B., Decuyper, M., Mervielde, I., 2006.
Five types of personality continuity in childhood and adolescence. Journal of Personality
and Social Psychology, 91, 538-552.
Eaton, N. R., Krueger, R. F., South, S. C., Gruenewald, T. L., Seeman, T. E., Roberts, B. W.,
2012. Genes, environments, personality, and successful aging: Toward a comprehensive
developmental model in later life. Journal of Gerontology, 67A, 480-488.
Fraley, C., Roberts, B.W., 2005. Patterns of continuity: A dynamic model for conceptualizing
the stability of individual differences in psychological constructs across the life course.
Psychological Review, 112, 60-74.
Gillespie, N. A., Evans, D. E., Wright, M. M., Martin, N. G., 2004. Genetic simplex modeling of
Eysenck’s dimensions of personality in a sample of young Australian twins. Twin Research,
7, 637-648.
Hopwood, C. J., Donnellan, M. B., Krueger, R. F., McGue, M., Iacono, W. G., Blonigen, D. M.,
Burt, S. A., 2011. Genetic and environmental influences on personality trait stability and
14
growth during the transition to adulthood: A three-wave longitudinal study. Journal of
Personality and Social Psychology, 100, 545-556.
John, O. P., Naumann, L. P., Soto, C. J., 2008. Paradigm shift to the integrative big five trait
taxonomy, in: John, O. P., Robins, R. W., Pervin, L. A. (Eds.), Handbook of personality:
Theory and research (3rd ed.). Guilford, New York, pp. 114-158.
Johnson, A. M., Vernon, P. A., Feiler, A. R., 2008. Behavioral genetic studies of personality:
An introduction and review of the results of 50+ years of research, in: Boyle, G. J.,
Matthews, G., Saklofske, D. H. (Eds.), The SAGE Handbook of Personality Theory and
Assessment: Volume 1 Personality Theories and Models. SAGE, London, pp. 145-173.
Kandler, C., 2012. Nature and nurture in personality development: The case of neuroticism
and extraversion. Current Directions in Psychological Science, 21, 290-296.
Kandler, C., Bleidorn, W., Riemann, R., Angleitner, A., Spinath, F. M., 2012. Life events as
environmental states and genetic traits and the role of personality: A longitudinal twin
study. Behavior Genetics, 42, 57-72.
Kandler, C., Bleidorn, W., Riemann, R., Spinath, F. M., Thiel, W., Angleitner, A., 2010. Sources
of cumulative continuity in personality: A longitudinal multiple-rater twin study. Journal of
Personality and Social Psychology, 98, 995-1008.
Kandler, C., Riemann, R., Angleitner, A., 2013. Genetic and environmental continuity and
change of energetic and temporal aspects of temperament in adulthood: A longitudinal
twin study of self- and peer reports. Developmental Psychology, 49, 1739-1753.
Kandler, C., Riemann, R., Spinath, F. M., Angleitner, A., 2010. Sources of variance in
personality facets: A multiple-rater twin study of self-peer, peer-peer, and self-self (dis-)
agreement. Journal of Personality, 78, 1565-1594.
Lucas, R. E., Donnellan, M. B., 2011. Personality development across the life span:
Longitudinal analyses with a national sample from Germany. Journal of Personality and
Social Psychology, 101, 847-861.
McAdams, D. P., Pals, J., 2006. A new Big Five: Fundamental principles for an integrative
science of personality. American Psychologist, 61, 204-217.
McCrae, R. R., Costa, P. T., 2008. The five-factor theory of personality, in: John, O. P., Robins,
R. W., Pervin, L. A. (Eds.), Handbook of personality: Theory and research (3rd ed.).
Guilford, New York, pp. 159-181.
McCrae, R. R., Terracciano, A., 78 Members of the Personality Profiles of Cultures Project,
2005. Universal features of personality traits from the observers perspective: Data from
50 cultures. Journal of Personality and Social Psychology, 88, 547-561.
Ormel, J., Riese, H., Rosmalen, J. G. M., 2012. Interpreting neuroticism scores across the
adult life course: Immutable or experience-dependent set points of negative affect?
Clinical Psychology Review, 32, 71-79.
Plomin, R., Lichtenstein, P., Pedersen, N. L., McClearn, G. F., Nesselroade, J. R., 1990. Genetic
influence on life events during the last half of the life span. Psychology and Aging, 5, 21-
30.
Riemann, R., Kandler, C., 2010. Construct validation using multitrait-multimethod-twin data:
The case of a general factor of personality. European Journal of Personality, 24, 258-277.
Roberts, B. W., Jackson, J. J., 2008. Sociogenomic personality psychology. Journal of
Personality, 76, 1523-1544.
Roberts, B. W., Kuncel, N. R., Shiner, R., Caspi, A., Goldberg, L. R., 2007. The power of
personality: The comparative validity of personality traits, socioeconomic status, and
cognitive ability for predicting important life outcomes. Perspectives of Psychological
Science, 2, 313-345.
15
Roberts, B. W., Walton, K. E., Viechtbauer, W., 2006. Patterns of mean-level change in
personality traits across the life course: A meta-analysis of longitudinal studies.
Psychological Bulletin, 132, 1-25.
Roberts, B. W., Wood, D., Caspi, A., 2008. The development of personality traits in adulthood
in: John, O. P., Robins, R. W., Pervin, L. A. (Eds.), Handbook of personality: Theory and
research (3rd ed.). Guilford, New York, pp. 375-398.
Spengler, M., Gottschling, J., Spinath, F. M., 2012. Personality in childhood: A longitudinal
behavior genetic approach. Personality and Individual Differences, 53, 411-416.
Turkheimer, E., Waldron, M., 2000. Nonshared environment: a theoretical, methodological,
and quantitative review. Psychological Bulletin, 126, 78-108.
van Dongen, J., Slagboom, P. E., Draisma, H. H. M., Martin, N. G., Boomsma, 2012. The
continuing value of twin studies in the omics era. Nature Reviews Genetics, 13, 640-653.
Vinkhuyzen, A. A. E., Pedersen, N. L., Yang, J., Lee, S. H., Magnusson, P. K. E., Iacono, W. G.,
McGue, M., Madden, P. A. F., Heath, A. C., Luciano, M., Payton, A., Horan, M., Ollier, W.,
Pendleton, N., Deary, I. J., Montgomery, G. W., Martin, N. G., Visscher, P. M., Wray, N. R.,
2012. Common SNPs explain some of the variation in the personality dimensions of
neuroticism and extraversion. Translational Psychiatry, 2, e102.
Yamagata, S., Suzuki, A., Ando, J., Ono, Y., Kijima, N., Yoshimura, K., Ostendorf, F., Angleitner,
A., Riemann, R., Spinath, F. M., Livesley, W. J., Jang, K. L., 2006. Is the genetic structure of
human personality universal? A cross-cultural twin study from North America, Europe,
and Asia. Journal of Personality and Social Psychology, 90, 987-998.
... The almost perfect genotypic stability in middle adulthood may reflect the importance to maintain the selected and created environments based on genetic differences in this period of life. Some studies indicate nonperfect genotypic stability in older age (> 70; see Figure 5b) indicating individual differences in genetically driven aging in later periods of life (see Kandler et al., 2015). ...
... b. Figure 5. Stability of phenotypic, genotypic, and environmental differences in personality traits as a function of age: Estimates are weighted by sample size (darker points, diamonds, and triangles carried more weight in the analysis) and based on (a) all 16 genetically informative longitudinal studies (see Table 1) or (b) the four selected studies which provided estimates for all Big Five traits corrected for error variance (DeFruyt et al., 2006;Kandler et al., , 2015Spengler et al., 2012). Note. ...
... b. Figure 6. Genetic and environmental contribution to the phenotypic stability of individual differences in personality traits as a function of age: Estimates are weighted by sample size (darker points, diamonds, and triangles carried more weight in the analysis) and based on (a) all 16 genetically informative longitudinal studies (see Table 1) or (b) the four selected studies which provided estimates for all Big Five traits corrected for error variance (DeFruyt et al., 2006;Kandler et al., , 2015Spengler et al., 2012). ...
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In this chapter, we introduce three perspectives of how quantitative behavior genetic modeling can broaden our knowledge about the etiology of personality differences, stability, and change. First, based on data from 14 cross-sectional, 13 longitudinal, and three cross-sequential studies, we illustrate age trends of the genetic and environmental contributions to individual differences in five personality trait dimensions: Neuroticism, extraversion, openness, agreeableness, and conscientiousness. Second, we demonstrate estimates of the stability of genetic and environmental differences in personality traits across time and different age groups using the data from 16 longitudinal studies. Finally, we visualize age trends of the genetic and environmental contributions to the stability of personality differences over the life course. We explain which implications these trends may have for the interplay between genetic and environmental sources during different stages of life and how they can deepen our understanding of personality development across the lifespan.
... Environmental factors (desha/kala), life events (major changes in life circumstances and social roles), cultural influences (jaati/kula), social factors (jaati/ kula), and biological factors (vaya/pratyatma niyata) etc all can influence the personality. [95] 'Mithyadrushtam ---pragnaaparadhajam' (Verse 6) 4 The above verse denotes cognitive distortions or cognitive errors or cognitive biases made by the physician while prognosticating. Cognitive biases (mithyadrushtam) and personality traits of the physiciain may affect clinical reasoning processes which may lead to errors in the diagnosis, management, or treatment of medical conditions. ...
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... Genetic influenced 50% in personality development. The other factor were social and parenting (Kandler & Bleidorn, 2015). The genetic had important role in individual. ...
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Physical and psychological changed were commonly happened in adolescents. Some of them felt over estimate, egocentric, peevish, and aggressive. It was influenced by society and family. Some researchers said that a child who lived with verbal abusing, they had psychological disorder such as anxiety, Post Trauma Distress Syndrome, depression, and personality disorder. The aim of this research was to know the association of parental verbal abuse and adolescent personality types in 2 Gamping Junior High School. The method was a quantitative research which used cross sectional design. The sample was 89 person who lived with parents and they were 12-14 years old. Sample was taken with simple random sampling. Researcher used students' number to take the sample. The questioners were verbal abuse questioner and Myers Briggs Type Indicator Personality. Next, the data was analyzed by SPSS 21 with coefficient contingency test. Based on the result, the p was 0.192 (sign p <0.05). It was shown that there was unrelated between parental verbal abuse and adolescent personality types in 2 Gamping Junior High School. Most of them (88.8%) were low parental verbal abuse. There were many factors which influenced the personality type, such as genetic, social, and perceptions. Further researchers said that Javanese norm could influence this situation. There were any norm which children must be allowed the parents. It made different perception of parental verbal abuse for adolescent. The result was not related between parental verbal abuse and adolescent personality types. There were many factors which influencing the personality type in individual, such as genetic, social, and perceptions.
... Otros autores han cuestionado la supuesta universalidad de los rasgos (Guerven, von Rueden, Massenkoff, Kaplan & Lero Vie, 2013) y la hipótesis que sostiene que los mismos sólo cambian debido a una maduración intrínseca (Roberts, Walton y Viechtbauer, 2006). Existe evidencia de que las influencias ambientales no tendrían un papel tan limitado como su-pone el MCF y que la personalidad tendría cambios significativos luego de los 30 años (Kandler, 2012;Kandler & Bleidorn, 2015). hay que mencionar también que existen otras líneas de trabajo que buscan construir una auténtica teoría de la personalidad, por sobre la simple generalización empírica que dio origen al modelo (Allik & McCrae, 2002). ...
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The conceptualization of personality disorders is going through a paradigm shift process. Obsolete categorical approaches are giving way to dimensional models, which promise a better understanding of this pathology. However, this paradigm shift process is far from being finalized. The discipline experiences a moment of uncertainty, given the need to leave an inefficient model but without saving yet a solid alternative one. This paper reviews the main aspects of this process, which includes the questioning of categorical models, the first dimensional approaches, the line of work that emerged from the proposal of the American Psychiatric Association, and the DSM-5's own dimensional proposal, wits the criticisms it brought. In addition, we expound on the dimensional proposal of the Big Five Factor Personality Model and its limitations. Finally, we reflect on the state of the art, where the proposal of the "Big Five" and the DSM-5 coexists without reaching a unified model, which should arise from the investigations that are being carried out.
... p < 0.05; see Table 1), prior research on this issue has produced somewhat mixed results (for an overview, see Specht, 2017). Metaanalytic evidence, for example, points toward relative stability in agreeableness during young and middle adulthood and a slight increase among older adults (Roberts et al., 2006; see also Roberts and Mroczek, 2008), whereas some recent studies have reported stable (e.g., Kandler and Bleidorn, 2015) or even decreasing (e.g., Wortman et al., 2012) agreeableness at older ages. Hence, longitudinal research could enable a more dynamic perspective on how age-related agreeableness trajectories could shape the age-EA linkage over time. ...
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... In sum, previous genetically informative studiesin particular twin studiesprovided strong and robust support for a genetic basis of individual differences in personality traits. Despite some variation in the size of heritability estimates across the Big Five personality traitsextraversion often tended to show the largest heritability and agreeableness the smallest (see Kandler and Bleidorn 2015, for an overview)these differences are not statistically important (Vukasović and Bratko 2015). The average broad-sense heritability of personality traits amounts to h 2 = .50, ...
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It is no longer controversial that genetic differences account for individual differences in all human traits, such as personality traits: About 40% to 50% of variation are attributable to genetic sources. Heritability estimates are even larger for more accurate measures of personality characteristics. The combined consideration of molecular genetic study results and findings from different genetically informative family studies yields that the genetic basis of personality traits reflects many gene variants of small effects, which interact in complex ways among each other and with environmental factors. Moreover, individual differences in the genetic makeup drive individual differences in experiences and thus influence the course of individual trait development within the opportunities provided by the environment.
... The environmentally triggered differences in gene expression (i.e., epigenetic differences inside the organism) between people with the same genotype (e.g., monozygotic twins) may appear as differences due to environmental influences not shared by twins. If those epigenetic effects accumulate within an individual's lifetime, then increases in (environmental) differences between genetically identical individuals over the lifespan may be attributable to an epigenetic drift (Kandler & Bleidorn, 2015). ...
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In this chapter, we provide theories on how genetic and environmental factors can additively contribute, transact, and interact inside and outside the organism to explain and bridge typical findings from quantitative and molecular genetic studies on personality differences and development. We integrate different theoretical models and elaborate the meaning of genetic and environmental variation in personality. Given equal access to environmental opportunities for development and increasing self-determination with development, individuals make their own choices and environments based upon their heritable personality characteristics. These environments in turn can reinforce or even change the individuals’ personality traits. Moreover, environments provide the range and variety of developmental opportunities, in which people develop differently depending upon their genetic sensitivity to environmental influences. From these perspectives, individual development is a function of closely intertwined genetic and environmental sources. Genetic differences in personality traits may primarily mirror genotype–environment correlations, whereas environmental variance may rather reflect interactions between genetic and individual environmental factors.
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