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Face preferences affect a diverse range of critical social outcomes, from mate choices and decisions about platonic relationships to hiring decisions and decisions about social exchange. Firstly, we review the facial characteristics that influence attractiveness judgements of faces (e.g. symmetry, sexually dimorphic shape cues, averageness, skin colour/texture and cues to personality) and then review several important sources of individual differences in face preferences (e.g. hormone levels and fertility, own attractiveness and personality, visual experience, familiarity and imprinting, social learning). The research relating to these issues highlights flexible, sophisticated systems that support and promote adaptive responses to faces that appear to function to maximize the benefits of both our mate choices and more general decisions about other types of social partners.
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doi: 10.1098/rstb.2010.0404 , 1638-1659366 2011 Phil. Trans. R. Soc. B
Anthony C. Little, Benedict C. Jones and Lisa M. DeBruine
Facial attractiveness: evolutionary based research
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Facial attractiveness: evolutionary based
Anthony C. Little1,*, Benedict C. Jones2and Lisa M. DeBruine2
Department of Psychology, University of Stirling, Stirling FK9 4LA, UK
School of Psychology, University of Aberdeen, Aberdeen, UK
Face preferences affect a diverse range of critical social outcomes, from mate choices and decisions
about platonic relationships to hiring decisions and decisions about social exchange. Firstly,
we review the facial characteristics that influence attractiveness judgements of faces (e.g. symmetry,
sexually dimorphic shape cues, averageness, skin colour/texture and cues to personality) and then
review several important sources of individual differences in face preferences (e.g. hormone levels
and fertility, own attractiveness and personality, visual experience, familiarity and imprinting,
social learning). The research relating to these issues highlights flexible, sophisticated systems
that support and promote adaptive responses to faces that appear to function to maximize the
benefits of both our mate choices and more general decisions about other types of social partners.
Keywords: attractiveness; mate choice; preferences; agreement; variation; individual differences
The human face has been a source of great interest to
psychologists and other scientists in recent years
because of the extraordinarily well-developed ability
of humans to process, recognize and extract infor-
mation from other’s faces (see other papers in this
volume). Our magazines and television screens are
not just filled with any faces—they are filled with
attractive faces, and both women and men are highly
concerned with good looks in a potential partner [1].
Physical appearance is important to humans and cer-
tain features appear to be found attractive across
individuals and cultures [2]. The same holds true
across the animal kingdom; most non-human species
rely on external traits, such as the size, shape and
colour of adornments (e.g. feathers, fur and fins) to
attract mates [3]. Research on animals has focused on
individual traits that are attractive across individuals,
and even species, such as symmetry [4].
Physical attractiveness has important social con-
sequences. For example, beauty is associated with
upward economic mobility, especially for women
[5,6], attractive people have more dates than less
attractive people [7], and people who have dated
more attractive individuals report being more satisfied
with their dates [8,9]. It has long been noted that there
exists a ‘What is beautiful is good’ stereotype [10]
([2,11,12] for meta-analytical reviews of research on
physical attractiveness stereotypes), whereby attractive
individuals are perceived to possess a variety of
positive personality attributions. In mock interviews,
attractive people are more likely to be hired than less
attractive individuals [13] and attractiveness can also
influence judgements about the seriousness of
committed crimes [14]. Outside the laboratory,
attractive people also appear to lead favourable lives;
attractive individuals pay lower bail [15] and are
more likely to be hired for jobs [16,17] than less
attractive individuals.
Despite research on social consequences, exactly
what it is that makes a face beautiful remains poorly
defined. One of the major deterrents in determining
the features of an attractive face lies in the widespread
belief that standards of attractiveness are learned
gradually through exposure to culturally presented
ideals (e.g. through the media in Western society)
and this has also led to a general belief that cultures
vary dramatically in what they perceive to be attractive
[18]. If this were true, it would mean that attractive-
ness is arbitrary and what is beautiful now could, in
a different time or place, be considered unattractive.
The well-known phrase ‘beauty is in the eye of the
beholder’ is a testament to our belief that attractiveness
is ephemeral. For example, the philosopher David
Hume is often quoted for making the argument that
beauty, ‘is no quality in things themselves: it exists
merely in the mind which contemplates them;
and each mind contemplates a different beauty’
[19, pp. 208– 209].
Darwin [20] was also struck by cultural differences,
such as those evident in preferences for skin colour,
body hair and body fat, and those revealed in practices
such as lip ornamentation and teeth filing, ‘It is cer-
tainly not true that there is in the mind of man any
universal standards of beauty with respect to the
human body’ (Darwin cited by [21]). Such convic-
tions were supported by early cross-cultural work
by Ford & Beach [22] who catalogued differences
between cultures in preferences for body weight,
*Author for correspondence (
One contribution of 10 to a Theme Issue ‘Face perception: social,
neuropsychological and comparative perspectives’.
Phil. Trans. R. Soc. B (2011) 366, 1638–1659
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breast size and other aspects of female physique and
suggested little consensus.
While individual and cross-cultural differences exist
(see later), this politically correct view of beauty is to
some extent false. In fact, agreement between individ-
uals is one of the best-documented and most robust
findings in facial attractiveness research since the
1970s. Across many studies it has been found that
there is a high degree of agreement from individuals
within a particular culture and also high agreement
between individuals from different cultures (see [2]
for a meta-analytical review). If different people can
agree on which faces are attractive and which are not
attractive when judging faces of varying ethnic back-
ground (e.g. [23]), then this suggests that people
everywhere are all using the same, or at least similar,
criteria in their judgements.
Cross-cultural agreement on attractiveness is evi-
dence against the notion that attractiveness ideals are
slowly absorbed by those growing up within a particu-
lar culture and this suggests that there is something
universal about attractive faces (and unattractive
faces) that is recognized both across individuals and
cultures. In the next section, we discuss traits that
are proposed to be generally attractive by reasoning
based on evolutionary theories, but we return to the
notion of individual variation later. While some traits
are proposed to be on average preferred across individ-
uals, an adaptive view of preference suggests that
individuals will indeed vary in what they prefer and
we examine differences in more detail in §3.
An evolutionary view assumes that perception and
preferences serve an adaptive function: the external
world provides information to guide biologically and
socially functional behaviours [24]. If in our evolution-
ary past, information was present about a person’s
mate and/or social value (e.g. provisioning ability, gen-
etic quality) in any way, then an advantage would
accrue to those who used these signs and those indi-
viduals would leave more genes behind in the next
generation. Theoretically then, preferences guide us
to choose mates who will provide the best chance of
our genes surviving. In many studies, this evolutionary
view of attractiveness has been used to predict the
specific characteristics of attractive faces (see [25] for
review). Sexual selection is the theoretical framework
for much work and a thorough discussion of this
topic in general is beyond the current review. Inter-
ested readers can see Andersson [3] for a thorough
review, including issues relating to how preferences
may arise in populations.
Although we can say whether a face is attractive or
unattractive, it is extremely difficult to articulate the
specific features that determine this attraction. There
are, however, several facial traits that have been
proposed to advertise the biological quality of an
individual in human faces, and hence to influence
attractiveness as a mate: traits such as symmetry, aver-
ageness and secondary sexual characteristics (see also
[26] for meta-analysis). There are many aspects of
‘quality’ that can be associated with certain traits but
these can be broadly split into two types of benefits
to the perceiver: direct benefits, whereby the perceiver
directly gains for themselves or their offspring, and
indirect benefits, whereby the perceiver gains genetic
benefits to their offspring. The former is relevant to
both same- and opposite-sex attractiveness judge-
ments, whereas the latter has consequences for
reproductive pairings. For example, avoiding a parasit-
ized mate has obvious direct advantages whether
parasite resistance is heritable or not [27] as there
are direct benefits to choosing a parasite-free mate.
Preferences for facial traits that are associated with
parasite resistance may be adaptive because this can
lead individuals to associate with those who are not
carrying contagious parasites (which may be passed
on to the individual or to the offspring) and who are
able to act as good parents (providing material benefits
or care). Individuals who are attracted to those having
face traits associated with parasite resistance may also
increase the chances of passing on heritable parasite-
resistant genes to their offspring. In other words,
there are several reasons why avoiding a parasitized
mate is advantageous. Ultimately it may be unneces-
sary to consider the relative weights of indirect and
direct benefits; both indirect and direct benefits are
likely to be important in evolution and their contri-
butions to attractiveness are difficult to tease apart.
We note that much research has focused on women’s
preferences, although most traits are also relevant
for men.
Symmetry refers to the extent to which one-half of an
object (image, organism, etc.) is the same as the other
half. Individuals differ in their ability to maintain the
stable development of their morphology under the pre-
vailing environmental conditions under which that
development is taking place [28,29]. The ability of
an individual to develop successfully in the face of
environmental pressures is therefore one proposed
indicator of genetic quality. A character demonstrates
fluctuating asymmetry (FA) when symmetry reflects
the normal development, and deviations from this
symmetry are randomly distributed with respect to
side [30]. FA is a particularly useful measure of devel-
opmental stability because we know that the optimal
developmental outcome is symmetry. Therefore, any
deviation from perfect symmetry can be considered a
sub-optimal solution which will result in performance
problems in the future. FA is also a useful measure as
it subsumes a huge amount of individual variation
in development, being the outcome of differences in
genetic (e.g. inbreeding, mutation and homozygosity)
and environmental (e.g. nutrient intake, parasite
load) factors [28,29]. Preferences for symmetry can
then, potentially, provide both direct (e.g. by avoiding
contagion) and indirect benefits (e.g. by providing
healthy genes for offspring) to the perceiver.
Whether symmetry is actually related to quality in
other animals and humans is an issue addressed by a
large literature, and a complete review is not the
focus of this paper. While the issue is divided, and
Review. Facial attractiveness A. C. Little et al. 1639
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there is some evidence that symmetry is not associated
with quality (e.g. [31]), many studies do show links
between symmetry and quality in many species
[28,29]. In humans, male body symmetry is positively
related to sperm number per ejaculate and sperm
speed [32] and female breast symmetry is positively cor-
related with fecundity [33,34]. Relating to faces, one
study has demonstrated that facial asymmetry is posi-
tively related to self-reported number of occurrences
of respiratory disease [35] and some studies have
observed positive correlations between symmetry and
other putative indices of underlying physical condition
(i.e. exaggerated sex-typical characteristics, [36,37]).
The relationship between symmetry and quality is not
reviewed in detail here, but it should be noted that fit-
ness-related characteristics, such as growth rate,
fecundity and survivability, are positively associated
with symmetry across a number of species and taxa
(e.g. [29]; see [38] for a review) and ultimately, any
link between symmetry and quality, no matter how
weak, is sufficient to create a selection pressure on the
opposite sex to choose symmetric mates in order to
provide genetic quality benefits to their offspring.
In humans, Thornhill & Gangestad [39] found that
the total number of sexual partners a man reported
having was positively related to skeletal symmetry.
Studies of naturally occurring human facial asym-
metries also provide evidence that symmetry is found
attractive, though such studies can be confounded
by potential correlates. Studies measuring symmetry
from unmanipulated faces have reported positive cor-
relations with rated attractiveness [4044] and one
study has even demonstrated that with pairs of
monozygotic twins, the twin with more symmetric
measurements is seen as more attractive [45].
While some studies directly manipulating human
facial images have found that asymmetry is preferred
to symmetry [46], manipulations used in these studies
tend to be crude, using ‘chimeric’ face images manu-
factured by aligning one vertically bisected half-face
with its mirror reflection. Studies using more sophisti-
cated symmetry manipulations have demonstrated that
symmetry can have a positive influence on attractive-
ness [47,48] and have established that the chimeric
manipulations used in the early studies introduced
unnatural proportions into the symmetric faces (see
[48]). Examples of manipulated images can be seen
in figure 1. Thus, the methodologically superior com-
puter graphic studies [47,48] parallel the findings of
investigations into naturally occurring facial asym-
metries [40,41,4345]. The computer graphic studies
demonstrate that increasing symmetry alone is suf-
ficient to increase attractiveness. Subsequently, other
studies have replicated preferences for symmetry
using manipulated stimuli in different Western samples
(e.g. [49,50]), but evidence for symmetry preferences
using these methods is not limited to western popu-
lations or even to humans. Preferences for symmetry
using manipulated faces have been found in African
hunter gatherers [51], and macaque monkeys gaze
longer at symmetrical than at asymmetrical face
images of conspecifics [52].
Importantly, recent studies have implicated percep-
tions of health in attraction to symmetric faces [44,53]
and have suggested that the mechanisms underpinning
preferences for symmetric faces are different from
those that might drive preferences for symmetry in
mate-choice-irrelevant stimuli (e.g. [49,50]). Such
findings suggest that preferences for symmetric faces
reflect, at least in part, adaptations for mate choice.
Averageness refers to how closely a face resembles
the majority of other faces within a population; non-
average faces have more extreme characteristics than
the average of a population. Average faces may be
attractive because an alignment of features that is
close to a population average is linked to genetic diver-
sity [54,55]. Thornhill & Gangestad [54]haveargued
that average faces may be preferred to less-average
faces because owners of average faces possess a more
diverse set of genes, which may result in less common
proteins to which pathogens are poorly adapted. Para-
sites are generally best adapted to proteins that are
common in the host population; hence, parasites are
adapted to the genes that code for the production of
these proteins. A second evolutionary theory for the
attractiveness of averageness in faces is that extreme
(non-average) genotypes are more likely to be homozy-
gous for deleterious alleles, that is, to be more likely to
possess genes that are detrimental to an individual than
those with more average genotypes [54]. Both of these
theories propose evolutionary benefits to mating with
individuals possessing average faces.
Recent studies have supported the link between aver-
ageness, heterozygosity (i.e. genetic diversity) and
attractiveness. Heterozygosity in the major histocompat-
ibility complex (MHC) genes that code for proteins
involved in immune response, is positively associated
with facial attractiveness [56] and facial averageness
[57]. More directly, another study has shown that facial
averageness is positively related to medical health as
measured from actual medical records in both men and
women [58]. Facial averageness can then be potentially
associated with both direct benefits in terms of associating
(a) (b)
Figure 1. Symmetry and asymmetry. (a) A shape-symmetric
facial composite and (b) asymmetric version. Features and
outline are marked on the faces in order to create sym-
metric/asymmetric versions. The asymmetric version has
had its asymmetry enhanced by 50%. Symmetric images
are usually preferred to asymmetric images.
1640 A. C. Little et al. Review. Facial attractiveness
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with healthy, parasite- and/or disease-free partners and
indirect benefits of heterozygous genes that can be
passed onto offspring.
There is good evidence that average faces are indeed
found attractive. Galton [59] first noted that multiple
faces blended together were more attractive than the
constituent faces. Recent studies have improved upon
these techniques using computers to create digitally
blended composite faces; generally, the more images
in a composite, the more attractive it is found [6062].
Aside from composite images, Light et al. [63]found
that, in unmanipulated male faces, more attractive
faces were rated as less distinctive, and Rhodes &
Tre mewa n [64] found that higher averageness was
associated with higher attractiveness when manipulating
averageness via digital caricaturing.
Average faces are generally more symmetric and
symmetry is typically attractive in faces (discussed in
more detail above). Several studies have controlled
for this confound in the original studies. When
averageness and symmetry were independently ma-
nipulated, one study found that both manipulations
positively and independently influenced attractiveness
judgements [65]. Other studies have used perfectly
symmetric images manipulated in averageness and
still have demonstrated preferences for averageness
[66,67]. Indeed, by comparing preferences for
averageness when the effects of symmetry were con-
trolled for and were not controlled for, Jones et al.
[66] demonstrated that the contribution of symmetry
to the attractiveness of average faces was minimal.
It has also been noted that, in the original com-
posite studies, the more images that are blended
together the smoother the skin texture becomes, as
imperfections such as lines or blemishes are averaged
[68]. Skin colour/texture has been controlled in studies
that normalize the texture/colour of all the faces seen
and all these studies demonstrate that average is
attractive [62,64,66,67]. Examples of composite
images and the effects of shape and colour averaging
can be seen in figure 2.
While the majority of the work described above has
been carried out in North America, Britain and
Australia, averageness has also been found to be attract-
ive across different cultures. For example, facial
averageness is also found attractive in Japanese
participants [69] and in African hunter– gatherers [67].
(c)Secondary sexual characteristics in faces
Male and female faces differ in their shape. Mature
features in adult human faces reflect the masculin-
ization or feminization of secondary sexual
characteristics that occurs at puberty. These face
shape differences, in part, arise because of the action
of hormones such as testosterone. Larger jawbones,
more prominent cheekbones and thinner cheeks are
all features of male faces that differentiate them from
female faces (e.g. [70]).
From an evolutionary view, extremes of secondary
sexual characteristics (more feminine for women,
more masculine for men) are proposed to be attractive
because they advertise the quality of an individual in
terms of heritable benefits; they indicate that the
owners of such characteristics possess good genes.
In other words, such traits advertise the possession
of genes that are beneficial to offspring inheriting
them in terms of survival or reproduction. One explan-
ation of the importance of these facial traits is that they
represent a handicap to an organism [71] and the
costs of growing the trait means that only healthy indi-
viduals can afford to produce them. In this way, these
‘honest’ handicaps are proposed to indicate the fitness
of the owner. For example, secondary sexual
characteristics are proposed to be linked to parasite
resistance because the sex hormones that influence
their growth, particularly testosterone, lower immuno-
competence. Testosterone has been linked to the
suppression of immune function in many species [72],
including humans [73,74]. Larger secondary sexual
characteristics should be related to a healthier
immune system because only healthy organisms
can afford the high sex-hormone handicap on the
immune system that is necessary to produce these
characteristics [75].
In many non-human animal studies, there is a
positive association between secondary sexual trait
Figure 2. Averageness. (a) A composite image made from
three images, (b) the same image given the colour of nine
images and (c) a shape and colour composite made from
nine images. Image (c) should be more attractive than both
of the other images. Composites are made by marking key
locations around the main facial features (e.g. points outline
the eyes, nose and mouth) and the outline of each face
(e.g. jaw line, hair line). The average location of each point
of the component faces is then calculated to define the
shape of the composite. The images of the individual faces
are then warped to the relevant average shape before super-
imposing the images to produce a photographic quality
composite image.
Review. Facial attractiveness A. C. Little et al. 1641
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expression and immunocompetence (e.g. [76]). The
relationship between masculinity/femininity and good
genes in humans is less clear. A study by Rhodes
et al.[77], however, has shown that perceived mascu-
linity correlated positively with actual measures of
health in male adolescents. No relationship was
found between femininity and actual health in female
faces, though [77]. Another study has demonstrated
that men’s facial masculinity and women’s facial fem-
ininity are negatively related to self reports of
respiratory disease [35]. If health is heritable, then
female preferences for masculinity and male prefer-
ences for femininity may indeed also reflect the
choice of mates with good genes. There is also a link
between hormonal profile and face shape. Women
with higher circulating oestrogen have more feminine
faces [78], while men with high testosterone have
more masculine faces ([79], but see also [80]).
If women with high oestrogen and men with high
testosterone are valued as mates, preferences for cues
of hormonal profile could drive preferences for sexu-
ally dimorphic face shape. Figure 3 shows faces
manipulated in facial masculinity and femininity.
There is considerable evidence that feminine female
faces are considered attractive. Studies measuring
facial features from photographs of women [40,81,
82] and studies manipulating facial composites [83]
all indicate that feminine features increase the attract-
iveness of female faces across different cultures. If
oestrogenized female faces provide cues to fertility
and health, then male preferences for such features
are potentially adaptive. This reasoning does not
require oestrogen to be immunosuppressive or part
of a handicap.
The link between masculinity and attractiveness in
male faces is less clear. Cunningham et al.[84] and
Grammer & Thornhill [40] used facial measurements
and found that women preferred large jaws in men.
‘Masculine’ features, such as a large jaw and a promin-
ent brow ridge are reliably associated with ratings of
dominance in photographic, identikit and composite
stimuli [83,8588]. Despite some findings showing a
preference for more masculine and dominant faces,
several studies have shown that feminine character-
istics and faces of low dominance are of increased
attractiveness [62,83,84,8991]. Many studies have
made use of computer graphic techniques to manipu-
late masculinity. Sexual dimorphism in face shape can
be manipulated by taking the geometrical differences
between average male and female face shapes and
applying this difference to new faces, making more
or less masculine or feminine versions [83].
This process simultaneously changes all dimorphic
shape characteristics in the face. For example, ‘mascu-
linizing’ a male face shape by increasing facial
proportions relative to the differences between a
male and female average increases the size of the jaw
and reduces lip thickness because male jaws are
larger than female jaws and the lips of men are thinner
than those of women. Perrett et al.[83] presented both
Japanese and Caucasian faces in their country of
origin. For the male face stimuli, the shape selected
by Caucasians as most attractive was significantly
feminized for both the Caucasian male face and the
Japanese male face continua. Similarly, Japanese
participants also selected significantly feminized ver-
sions of the male stimuli for both the Japanese and
Caucasian male face continua. Thus, in both cultures
it was found that participants showed a preference for
feminized male faces. Since then, several studies have
also documented preferences for femininity [62,90,
92,93], but some similar computer graphic studies
have also reported preferences for masculinity [94,
95]. Although some of this variation may be attributed
to other characteristics of the faces that varied between
sets of stimuli [96], this does not explain the variability
in preferences. We discuss the sources of individual
differences in preferences for sexually dimorphic
shape cues in the latter sections of our article.
(d)Skin health and colour
The face traits discussed so far have often been
measured and manipulated but also studied in terms
of perception and related to attractiveness. The
reasoning for why traits like symmetry are preferred
is often related to underlying health. Thus, it is import-
ant to examine perceptions of facial health directly.
Perceived health is difficult to relate to any one
metric, but people will readily rate faces for perceived
health and show very high agreement on such ratings
(e.g. [44,97]). See figure 4 for examples of healthy
and unhealthy appearing traits. In evolutionary terms,
(a) (b)
Figure 3. Masculinity/femininity in faces. (a) Male and
female composite images made more masculine and (b)
more feminine. Masculinity is transformed using the differ-
ence between male and female face shape as defined by
creating a male and female composite. Preferences for mas-
culinity in male faces vary across studies, but feminine
female faces are consistently found more attractive than mas-
culine female faces.
1642 A. C. Little et al. Review. Facial attractiveness
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there is a large and obvious selective advantage in
detecting healthy partners both for social exchange
and mate choice. Indeed, while the role of health in
mate preferences is clear (see below), recent work
has demonstrated that participants are more willing
to reciprocate trust from healthy-looking social part-
ners than from social partners who are relatively
unhealthy-looking [98]. Such findings demonstrate
the importance of health perceptions for social inter-
action generally. Again, as for previous traits, there
may be both direct and indirect benefits to partnering
with individuals who are perceived to be healthy.
There have been several studies that have addressed
how facial appearance relates to the healthiness of an
individual in humans. The three traits discussed
above are often manipulated by changing only face
shape, but health perception appears to be related to
facial colour and texture also. Fewer studies have
examined how colour and texture of faces influence
attractiveness judgements. One study has examined
how well ratings of health from small patches of skin
of faces are related to overall rated attractiveness
when the whole face image is available. Jones et al.
[43] found that apparent health of facial skin is
positively correlated with ratings of male facial attract-
iveness. In other research, homogeneity of skin colour
was positively related to attractiveness [99]. Findings
have also suggested that more heterozygous men also
have healthier appearing skin [56]. Skin health may
be a particularly useful marker of current health
condition as it is more changeable than aspects such
as symmetry or averageness.
Coloration is directly related to the appearance of
skin. Coloration also appears to be an important com-
ponent of sexual selection in many species. Red
coloration is associated with dominance in fish [100],
birds [101] and non-human primates [102,103] and,
consequently, is linked to attracting the opposite sex.
Recent evidence has suggested that primate trichro-
matic vision is an adaptation to distinguish colour
modulations in skin based on blood flow, allowing
assessment of the state and/or mood of conspecifics
[104]. It has been noted that primates with trichro-
matic vision are generally bare-faced [104] and that,
at least in humans, facial flushing is associated with
anger and confrontation [105].
In research on non-human primates, there has been
much interest in colour. For example, experimental
manipulation of colour shows that female rhesus
macaques prefer images of redder male faces [103],
while males prefer images of redder female hindquar-
ters [106]. In mandrills, red facial colour is related to
rank in males [102], and females sexually present
more frequently to brighter males and also groom
them more frequently [107]. Red coloration also has
consequences for behaviour in other species. For
example, in bird species, the addition of red to stimuli
can increase social dominance [108].
In humans, it has been shown that wearing red in a
variety of physically competitive sports is associated
with an increased chance of winning over opponents
[109]. This has been interpreted as natural associ-
ations of red with dominance being extended to
artificially displayed red in the same way that artificial
stimuli can exploit innate responses to natural stimuli
[108,110]. One study pitting red versus blue shapes
found that red shapes were seen as more aggressive,
dominant and more likely to win in physical com-
petitions [111]. Red does generally seem to have
aversive effects on human behaviour. For example,
when taking exams, individuals move their body
away from tests with red covers more than they do
from those with green or grey covers [112]. While
these studies suggest the colour red may be seen as a
threatening stimulus in humans, red also appears to
enhance attraction in some instances. For example,
women are seen as more attractive by men when pre-
sented with red backgrounds or with red clothing,
relative to other colours [113]. This effect appears to
be specific to attractiveness judgements; red colour
does not influence judgements of other traits such as
kindness or intelligence and does not influence
women’s attractiveness judgements of other women
[113]. Further research has examined red coloration
in faces and demonstrated a positive association with
perceived health [114]. The authors suggest that per-
ception of healthy, oxygenated blood may drive
associations between red and healthiness. Alongside
redness, people also appear to think that skin yellow-
ness is associated with healthy appearance in faces
[114]. Yellowness may advertise health via an associ-
ation with diet, as carotenoids are associated with
skin yellowness and are absorbed via the intake of
fruit and vegetables [114]. Taken together, these
studies suggest that information on attractiveness and
health is available from surface skin and that facial
attractiveness is not dependent only on traits that dis-
play limited variation in adult life: skin texture and skin
colour can vary over weeks or even days.
(e)Facial cues associated with personality
In a classic social psychology study, Dion et al.[10]
found that strangers rated attractive people as posses-
sing ‘socially desirable’ traits to a greater extent than
unattractive people, and that attractive people were
also expected to lead better lives than unattractive
(a) (b)
Figure 4. Facial healthiness. (a) Composite images of 15
women rated as high on healthiness and (b) 15 women
rated as low on healthiness. High healthiness is associated
with higher ratings of attractiveness.
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people. For example, attractive individuals were
thought to be able to achieve more prestigious occu-
pations, be more competent spouses with happier
marriages and have better prospects for personal fulfil-
ment. There has been a wealth of studies examining
this attractiveness stereotype, demonstrating that
attractive people are seen in a positive light for a
wide range of attributes compared with unattractive
people. On the basis of such studies, it has been
suggested that there exists a stereotype associated
with physical attractiveness, famously—‘What is
beautiful is good’ [2] (see [11,12] for meta-analytical
reviews of research on physical attractiveness
Studies on attractiveness stereotypes have generally
not addressed the particular characteristics of faces
that make individuals either attractive or unattractive,
or the features that elicit personality attributions,
although different faces reliably elicit the same person-
ality attributions [115]. Expression certainly has large
effects, with, for example, faces shown with smiles
rated as more attractive and as having more positive
personality traits than neutral faces (e.g. [116]).
Such facial expressions are transient, however, and
will differ rapidly within individuals over time and
across photographs. Both baby-like and mature/dom-
inant facial qualities are related and are more stable
aspects of appearance that reliably elicit personality
attributions cross-culturally (e.g. [88,117]), but their
effect on attractiveness judgements, at least of men,
is still in dispute, as noted earlier. Despite some find-
ings showing a preference for more masculine and
dominant male faces (e.g. [40]), several studies have
shown that feminine characteristics and faces of low
dominance are of increased attractiveness [84,89].
Personality traits are reported cross-culturally to be
among the most important factors in partner choice
by both sexes [1,118]. If desired personality is so
important, it would appear likely that personality
attributions elicited by a face would affect its attract-
iveness. For example, women who value cooperation
and good parenting may avoid masculine-faced men.
Thus, instead of feminine faces being attractive and
this attractiveness driving positive personality attribu-
tions, it may be that the personality attributions are
driving the attractiveness judgements.
Individuals may use personality stereotypes in mate
selection to select partners with a personality that they
desire. Some perceptual attributions to facial photo-
graphs are somewhat accurate (e.g. [119]), and so
choosing a partner based on perceived personality
may result in acquiring a partner who actually pos-
sesses desired personality traits. Attraction to faces
based on personality stereotypes may happen regard-
less of whether attributions are accurate or not,
especially as many individuals do believe that face pro-
vides an important guide to character [115,120].
In fact, it is possible that visually appearing to possess
certain traits may be more important in initial selec-
tion processes than actually possessing desired traits
because the visual stereotypes are more easily available
than information about stable behaviour. One study
has indeed demonstrated that a desire for some
personality traits influences judgements of facial
attractiveness [121]. Individuals valuing particular
personality traits find faces appearing to display these
traits attractive. Conversely, those not valuing particu-
lar traits find faces attractive that are perceived to
possess that trait less. Thus, desired personality influ-
ences perceptions of facial attractiveness in opposite
sex faces, changing the result to: ‘what is good is beau-
tiful’ [121]. In terms of benefits to perceivers, it is easy
to see why traits such as appearing trustworthy would
make a face appear more attractive. For individual-
specific traits, the logic is more complicated, but
such preferences could be related to behavioural com-
patibility within couples, as people do tend to desire
partners with personalities similar to their own [122].
One reason for variability in preferences for male
facial masculinity may lie in the personality traits that
masculine- and feminine-faced men are assumed to
possess. Increasing the masculinity of face shape
increased perceptions of dominance, masculinity and
age but decreased perceptions of warmth, emotional-
ity, honesty, cooperativeness and quality as a parent
[83]. Cunningham et al.[84] have suggested that,
because both masculine and feminine faces are only
rated as moderately attractive, a resolution to this con-
flict could be that very attractive male faces possess
a combination of factors and so reflect ‘multiple
motives’ in female mate choice (i.e. the desire for a
dominant and a cooperative partner, as advertised by
a combination of masculine and feminine features).
It appears then that ‘socially valued’ traits such as
honesty, warmth, cooperation and skill as a parent
are associated with feminized versions of male faces,
while traits such as dominance are associated with
masculinized face shapes. Indeed, recent work has
shown that masculine facial characteristics are associ-
ated with indices of physical dominance, such as
physical strength [123], and the perception of such
traits [124], and that feminine men show weaker pref-
erences for short-term relationships and stronger
preferences for committed, long-term relationships
than their masculine peers do [125]. Feminization of
male face shape may increase attractiveness because
it ‘softens’ particular features that are perceived to be
associated with negative personality traits. Women’s
face preferences may thus represent a trade-off be-
tween the desire for good genes and the desire for a
cooperative partner. This trade-off means that mascu-
linity may be more or less attractive under certain
contexts and to certain individuals; we discuss this
in §3.
(f)Other traits and interactions
Of course, the five types of trait listed above are not a
complete list of factors involved in the judgement of
facial attractiveness. Other face traits include factors
such as age [126], weight/adiposity [127], hair and
eye colour [128], facial hair in men [129] and make-
up use in women [130]. Similarity to self also appears
to be an influential trait and we review this factor in
more detail in §3bas self-similar preferences vary
according to social context [131,132].
While individual traits impact on attractiveness, there
is also scope for interaction between them. We review
1644 A. C. Little et al. Review. Facial attractiveness
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studies on interactions between emotion and attention in
§3bas preferences for these traits also change according
to social context. Certain face traits also appear to inter-
act in generating preferences, however. For example,
preferences for masculinity vary as a function of the
healthiness of the face [96] and women’s preferences
for facial self-similarity are higher when men are more
facially masculine [133]. Such interactions highlight
that facial attractiveness judgements are not simple:
many factors contribute to facial attractiveness and
these factors can interact with one another.
In humans, while individuals may share certain basic
criteria for finding faces attractive, many factors may
influence the specific types of face they find attractive.
In this section, we review three broad areas leading
to individual differences in preferences: internal
factors (e.g. hormonal state), context (e.g. mate-
choice versus same-sex preferences) and exposure
(e.g. visual experience).
(a)Internal factors
Research suggests that internal factors predict individ-
ual differences in several aspects of face perception,
including attractiveness judgements. Importantly, the
nature of these individual differences suggests adaptive
design in face perception and face preferences. In the
following section, we discuss two broad types of
internal factors: (i) those related to hormone levels
and fertility and (ii) those related to own condition,
attractiveness and personality.
(i) Hormone levels and fertility
The influence of hormones on face perception is an
area that has generated a considerable amount of
empirical research in recent years. As detailed pre-
viously, masculine characteristics in men’s faces are
associated with measures of long-term medical health
[35,77] and indices of developmental stability [36,37],
physical strength [123] and reproductive potential
[134]. By contrast, feminine characteristics in men’s
faces are associated with cues of investment and stron-
ger preferences for long-term over short-term sexual
relationships (e.g. [125]). There is now compelling
evidence that how women resolve this trade off
between the costs and benefits associated with choos-
ing a masculine mate is affected by hormone levels
and fertility.
Many studies have reported that women demon-
strate stronger preferences for men displaying mas-
culine facial characteristics around ovulation, when
women are most fertile, than during other phases of
the menstrual cycle [135 138]. Some studies have
also reported that these cyclic shifts in women’s prefer-
ences for masculine characteristics in men’s faces are
greatest among women who already have romantic
partners and when women judge men’s attractiveness
for short-term, extra-pair relationships [138].
Although the ultimate function of these cyclic shifts
remains somewhat controversial, many researchers
have interpreted cyclic shifts in women’s masculinity
preferences as evidence for adaptations that function
to increase offspring health via high paternal invest-
ment from a long-term partner while promoting
attraction to other men displaying cues of heritable
immunity to infectious disease when most fertile (dis-
cussed in [139]). Women may gain maximal benefits
by selecting investing long-term partners and high-
quality extra-pair partners. Importantly, other explan-
ations that have been suggested, such as increased
attraction to individuals who appear to be likely
sources of high-quality care and support during
phases of the menstrual cycle when increased pro-
gesterone prepares the body for pregnancy (i.e. the
non-fertile, luteal phase), are not necessarily mutually
exclusive with the more widely posited accounts that
emphasize indirect benefits of women’s mate choices
(discussed in [140]). Increased attraction to masculine
men is by no means unique to face preferences;
women also demonstrate stronger attraction to mas-
culine men when judging the attractiveness of men’s
voices [141143], body shapes [144] and body
odours [145], as well as when judging the attractive-
ness of videoclips of male behavioural displays of
dominance [146,147]. Furthermore, converging
evidence for fertility-related variation in women’s
preferences for facial masculinity comes from studies
investigating circum-pubertal and circum-menopausal
variation in women’s masculinity preferences; post-
menopausal and pre-pubertal women report weaker
preferences for masculine facial characteristics
than do their pre-menopausal and post-pubertal
counterparts, respectively (e.g. [148,149]).
The ultimate function of cyclic shifts in women’s
preferences for masculine facial characteristics is
not the only controversial aspect of cyclic shifts in
women’s masculinity preferences. For example,
although some researchers have suggested that cyclic
shifts in women’s masculinity preferences may be an
artefact of the computer graphic methods that are
generally used in these studies to experimentally
manipulate sexually dimorphic cues in digital face
images [150], this claim is very difficult to reconcile
with findings from studies that have demonstrated
cyclic shifts in women’s preferences for masculinity
in real (i.e. unmanipulated) face images [151] and
with the converging evidence for cyclic shifts in
women’s preferences for masculinity from studies
that have assessed preferences for masculinity in
other domains (e.g. behaviour, personality descrip-
tions, body odour) and that did not use computer
graphics to prepare their stimuli (e.g. [146,147]).
While these findings suggest that cyclic shifts in
women’s masculinity preferences are not an artefact
of the stimuli used, an aspect of research on cyclic
shifts in women’s masculinity preferences that remains
controversial is whether the effect of cycle phase on
women’s face preferences is relatively specific to judge-
ments of men’s faces, or also occurs when women
judge the attractiveness of other women. To date, evi-
dence is equivocal; some studies have observed cyclic
shifts in women’s preferences for masculine-faced
men, but not masculine-faced women [135], while
others have observed cyclic shifts in women’s prefer-
ences for masculine faces, irrespective of their sex
[136,152]. These latter papers speculate that cyclic
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shifts in women’s preferences for masculine-faced
women could represent a low-cost functionless by-
product of a mechanism that evolved primarily to
increase women’s preferences for masculine men
around ovulation [136], or have suggested that
higher attractiveness ratings given to masculine
women around ovulation could reflect increased dero-
gation of feminine, and therefore attractive, same-sex
competitors when women are most fertile [152] (see
also [149]).
In addition to the sex-specificity of the effects of
cycle phase on face preferences, the mechanisms that
underpin cyclic shifts in women’s preferences for mas-
culine characteristics in men’s faces have also been a
topic of considerable interest in recent years. For
example, research into the hormonal mechanisms
that might underpin these cyclic shifts has variously
emphasized the effects of variation in levels of tes-
tosterone [152], oestrogen [153] and progesterone
[136,141], or has suggested, perhaps unsurprisingly,
that cyclic shifts in women’s masculinity preferences
might be best explained by complex interactions
among multiple hormones [142,152]. While findings
from research into the hormonal mechanisms that
might underpin cyclic shifts in women’s masculinity
preferences have arguably been inconsistent, the find-
ings of corresponding research into the psychological
mechanisms have been relatively consistent; various
studies have demonstrated that women are quicker to
categorize men and access male stereotypes around
ovulation (e.g. [154,155]) or have suggested that
women’s preferences for masculine men are correlated
with their level of sexual desire [156,157]. These
findings suggest that cyclic variations in stereotype
access and sexual desire might be important psycho-
logical mechanisms for regulating facial masculinity
preferences during the menstrual cycle.
While research on hormone-mediated face percep-
tion has generally focused on women’s judgements
of men’s attractiveness, some recent research has in-
vestigated hormone-mediated face preferences among
men. Men, of course, do not cycle in the same way
women do, but levels of testosterone fluctuate within
individuals. Research using natural variation in testos-
terone has shown that men’s preferences for feminine
characteristics in women’s faces are stronger when
their testosterone levels are high than when they are
relatively low [158]. This finding suggests that
hormones, such as testosterone, can generate within-
participant individual differences in face preference
in men.
As can be seen from the previous paragraphs, there
is compelling evidence that women’s preferences for
masculine men, be they assessed from face preferences
or from preferences for male characteristics in other
domains, vary systematically over the menstrual
cycle. Whether or not preferences for other putative
cues of men’s long-term health are similarly affected
by menstrual cycle is equivocal, however. For example,
although many studies have demonstrated that
women’s preferences for the body odours of symmetric
men are enhanced around ovulation (reviewed in
[139]), evidence for cyclic shifts in women’s prefer-
ences for symmetry in men’s faces is inconsistent.
One study has found that women’s preferences for
symmetric male faces were stronger around ovulation
than during other phases of the menstrual cycle, at
least among partnered women who were instructed
to judge men’s attractiveness as short-term mates
[159]. By contrast, other studies have observed no
evidence for cyclic shifts in women’s preferences for
symmetric men’s faces (e.g. [150]), although one
study with a null finding for preference did find that
women’s ability to detect asymmetries in men’s faces
varied over the menstrual cycle in the predicted
manner [160]. Given that women’s preferences for
symmetry and masculinity in men’s faces are correl-
ated across individuals [161], suggesting that facial
masculinity and symmetry signal some shared infor-
mation and that women respond to them in similar
ways, the inconsistent effects of cycle phase on
women’s preferences for facial symmetry are rather
Although evidence that women’s preferences for
symmetry in men’s faces vary systematically over the
menstrual cycle is equivocal, that is not to say that
robust cyclic shifts in women’s perceptions of faces
are only evident in their preferences for facial mas-
culinity. For example, women’s aversions to self-
resembling faces are enhanced around ovulation and
positively correlated with women’s estimated pro-
gesterone levels during the menstrual cycle [162].
This variation in attitudes to self-resembling faces
may reflect increased inbreeding avoidance around
ovulation and increased preferences for caring, sup-
portive and trustworthy individuals when increased
progesterone prepares the body for pregnancy [163].
Moreover, women’s aversions to facial cues associated
with current illness (e.g. pallor) are also greater when
increased progesterone level prepares the body for
pregnancy, potentially reflecting mechanisms to com-
pensate for maternal immunosupression during the
early stages of pregnancy and helping to maintain
normal foetal development [97,136]. Indeed, pregnant
women and women using oral contraceptives which
mimic the effects of increased progesterone during
pregnancy demonstrate stronger aversions to individ-
uals displaying facial cues of illness than do women
with natural menstrual cycles [97]. These latter
findings for aversions to facial cues of illness and pro-
gesterone during the menstrual cycle complement
other research on increased aversions to possible
sources of contagion in women’s food preferences
during pregnancy [164], as well as increased sensitivity
to facial expressions signalling that sources of threat
and contagion are nearby when progesterone levels
are raised [165,166].
While our discussion of hormone-mediated face
preferences in women has emphasized the positive
findings that have been reported in the literature, it is
important to note that there have also been unsuccess-
ful replications of cyclic variation in women’s face
preferences. For example, two recent studies observed
no evidence for cyclic variations in women’s prefer-
ences for masculine versus feminine male faces
[150,167]. One possible explanation of these null find-
ings comes from findings that suggest the extent to
which women’s preferences for masculine men vary
1646 A. C. Little et al. Review. Facial attractiveness
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over the menstrual cycle vary systematically among
women. For example, cyclic variation in women’s pref-
erences for masculine characteristics in men’s voices is
significantly greater among women with high trait (i.e.
average) oestrogen levels than it is among women with
relatively low trait oestrogen levels [142]. This pattern
of results may occur because varying their sexual
strategy during the menstrual cycle may benefit un-
attractive women more than it benefits attractive
women [142]. More recent research has presented
additional evidence that women’s family background,
prenatal hormone levels and mortality salience might
also affect the extent to which they vary their masculin-
ity preferences according to their menstrual cycle phase
[168170]. We also note that there are significant
methodological differences between studies examining
cycle effects, making direct comparisons (e.g. between
those reporting null and positive effects) difficult. For
example, some studies distinguish between short- and
long-term mating contexts, generally with larger cyclic
shifts for short-term judgements [139], while others
do not [167]. Studies also differ in stimuli number,
stimuli type and how fertility is defined. A thorough
description of methodological differences between
studies is not the focus here, but methodology is
certainly a factor that could explain differences in find-
ings across studies. It is likely that further research
concerning individual differences in cyclic shifts and
comparing different methodologies would provide
important insights into the motivations, functions and
mechanisms behind cyclic shifts in fundamental aspects
of face perception.
(ii) Own condition, attractiveness and personality
While the previous section discussed research im-
plicating hormone levels and fertility in individual
differences in face perception, this section will discuss
the relationships between face preferences and indices
of own condition and attractiveness.
Several studies have reported positive correlations
between women’s ratings of their own physical attrac-
tiveness and the strength of their preferences for
masculine characteristics in men’s faces [92]. Other
studies have extended this work by demonstrating
that more objective measures of women’s condition
and attractiveness, such as their waisthip ratio or oes-
trogen levels, predict their preferences for masculine
characteristics in men’s faces in the same way
[171,172]. Similar correlations between indices of
women’s own attractiveness and the strength of their
preferences for masculine characteristics in other
domains, such as men’s voices, have also been
reported [173,174], and indices of women’s own con-
dition and attractiveness are positively correlated with
the strength of their preferences for symmetry and
healthy-looking skin in men’s faces [92,175].
The findings described above appear to be some-
what analogous to condition-dependent preferences
observed in other species, in which individuals in
good physical condition show stronger preferences
for high-quality mates (e.g. [176]). Condition-depend-
ent preferences in both humans and non-humans may
have a common function and occur because individ-
uals in good physical condition (i.e. attractive
individuals) are better able to compete for and/or
retain high-quality mates [92]. Particularly compelling
evidence for this proposal comes from one of the few
experimental studies of condition-dependent mate
preferences. Little & Mannion [95] showed that
women who viewed a slideshow of highly attractive
women reported lower self-rated attractiveness and
demonstrated weaker preferences for masculine char-
acteristics in men’s faces than did women who
viewed a slideshow of relatively unattractive women.
These findings suggest that women recalibrate sub-
jective impressions of their own attractiveness (i.e.
impressions of their own ‘market value’) according to
their recent experience with same-sex competitors
and that this, in turn, leads to a recalibration of their
mate preferences. While early work on the role of
own attractiveness in mate preferences emphasized
the importance of the judge’s own health, Little &
Mannion’s findings suggest that condition-dependent
preferences might be more usefully conceptualized as
‘market value dependent preferences’.
While the research described above focused on the
relationships between mate preferences and both
individuals’ own physical characteristics and their sub-
jective evaluations of these physical characteristics,
other work on condition-dependent preferences has
investigated whether personality traits and other
psychological factors predict individual differences
in mate preferences in similar ways. For example,
individual differences in systemizing and sensation-
seeking, both of which are components of male sex-
typical psychology, are positively correlated with
men’s preferences for feminine characteristics in
women’s, but not men’s, faces [177,178]. Among
women, individual differences in empathy, a com-
ponent of female sex-typical psychology, and extraver-
sion, a key predictor of social status that is correlated
with women’s physical attractiveness, are positively
correlated with preferences for masculine character-
istics in men’s, but not women’s, faces [177,179].
These findings not only implicate personality traits in
individual differences in face preferences but also
raise the intriguing possibility that some personality
traits might mediate the relationships between an
individual’s physical characteristics and their face
While factors such as hormones and own attractive-
ness can explain differences in face preferences
between individuals, the context under which judge-
ments are made can also contribute to variation in
standards of beauty. In the following section, we dis-
cuss how context affects face preferences in three
types of contexts: (i) social contexts, such as when jud-
ging potential mates versus potential cooperative
partners; (ii) temporal contexts, such as long- versus
short-term relationships; and (iii) environmental con-
texts, such as environments with high versus low
pathogen load.
(i) Social context
Information about genetic kinship is available in the
face and is perceived somewhat accurately [180 184].
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Judgements of facial similarity are highly synonymous
with judgements of kinship [185 187], and facial
similarity produced by computer-graphic manipulation
affects behaviour in ways consistent with inclusive fit-
ness theory (e.g. increasing cooperation in economic
games; [188,189]). Therefore, responses to facial
resemblance are likely to be affected by prosocial
versus sexual contexts.
Cues of kinship are predicted to increase prefer-
ences in non-sexual, prosocial contexts, owing to the
benefits associated with inclusive fitness [190]. In
other words, evolutionary models show that behav-
iours that benefit other individuals who share genes
through common descent will be favoured. Therefore,
if physical similarity is a reliable cue of genetic related-
ness, we expect individuals to act prosocially towards
individuals who appear similar to themselves. How-
ever, cues of kinship should have a less positive effect
in sexual contexts, because of inbreeding’s detrimental
effects on offspring quality [191]. One study in-
vestigated this prediction by comparing perceptions
of the attractiveness of self-resembling own-sex and
opposite-sex faces [131]. Male and female ‘siblings’
of both male and female participants were manu-
factured using computer-graphic methods detailed
in DeBruine et al.[163]. Participants judged self-
resemblance to be more attractive in the context of
own-sex faces than in the context of opposite-sex
faces. However, there was no such opposite-sex bias
when the same faces were judged for averageness.
This own-sex bias in preferences for self-resemblance
indicates that, while self-resemblance is attractive in
an exclusively prosocial (i.e. nonsexual) context, it is
less attractive in a potential mating context. Stronger
attraction to cues of kinship in own-sex faces than
in opposite-sex faces is likely to promote prosocial
behaviour towards own-sex kin, while minimizing
occurrences of inbreeding with opposite-sex kin.
Examples of manipulations of self-similarity can be
seen in figure 5.
Further evidence for context sensitivity in judge-
ments of self-resembling faces is provided by a study
comparing men’s and women’s preferences for self-
resemblance in opposite-sex faces in explicitly proso-
cial versus sexual contexts [132]. Participants were
shown images of self-resembling opposite-sex faces
and asked to judge their trustworthiness (i.e. prosocial
context), attractiveness for a short-term relationship
(i.e. sexual context) and attractiveness for a long-term
relationship (i.e. both prosocial and sexual context).
Consistent with both inclusive fitness and inbreeding
avoidance theories, self-resemblance increased percep-
tions of trustworthiness, decreased attractiveness for
short-term relationships and had no significant effect
on attractiveness for long-term relationships. The fact
that self-resemblance in opposite-sex faces was found
to be trustworthy, but not attractive in short-term con-
texts, emphasizes the context-sensitivity of responses
to self-resemblance. Importantly, because familiarity
increases judgements of both attractiveness and trust-
worthiness [192], this pattern of context-sensitivity
strongly suggests that responses to self-resemblance
do not occur simply because of familiarity alone (i.e.
the mere exposure effect [193]).
Another example of social context influencing
face preferences comes from research on interactions
among the effects of different facial characteristics on
preferences. For example, both behavioural and neuro-
biological evidence suggest that viewers demonstrate
stronger attraction to attractive physical cues in faces
(e.g. attractive face shapes or attractive colour) when
viewing faces demonstrating positive social interest in
the viewer than when viewing faces that appear un-
interested in the viewer (e.g. [194,195]). Similarly,
behavioural and neurobiological evidence also suggests
that viewers demonstrate stronger attraction to cues
associated with positive social interest (e.g. eye contact
and perceiver-directed smiles) when viewing physically
attractive individuals than when viewing relatively
unattractive individuals (e.g. [196199]). Such find-
ings may reflect mechanisms for efficient allocation
of mating and/or social effort and can be further
modulated by social context. Conway et al.[196],
for example, found that men and women showed
stronger preferences for perceiver-directed smiles
from opposite-sex than own-sex individuals when
judging others’ attractiveness, but not when judging
their likeability.
(ii) Temporal context
The trade-off theory of women’s masculinity prefer-
ences proposes that contextual factors that alter the
relative importance of the benefits and costs associated
with choosing a masculine partner (see §2cabove) will
affect the strength of women’s preferences for mascu-
line versus feminine men [25,83,92,93,138,200202].
Figure 5. Transforms of self-similarity. (a) Original picture,
(b) self-similar and (c) self-dissimilar opposite-sex images.
Images are made by using the difference between a compo-
site image of the same sex and an individual participant to
make faces more similar to the participant. Self-dissimilar
faces can be made by applying the same technique but
using images other than the participant.
1648 A. C. Little et al. Review. Facial attractiveness
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For example, women can only make use of the benefit
of genetic health for offspring when they are able to
conceive and, as discussed above (§3a(i)), women’s
preferences for masculine men are modulated by
their fertility. Similarly, the putative costs of low invest-
ment are much less of a concern in short-term than
in long-term relationships and, thus, women may
demonstrate stronger masculinity preferences when
judging men’s attractiveness as possible short-term
than long-term partners.
Little et al.[93] tested this prediction by measuring
women’s masculinity preferences separately in the
context of a short-term and a long-term relationship.
Participants interactively manipulated a male face
along a continuum from 50 per cent feminized to
50 per cent masculinized until it was ‘closest to the
appearance you would find attractive for a short- (or
long-) term relationship’. Women who were not
using oral contraceptives made this face more mascu-
line in the context of a short-term relationship than
in the context of a long-term relationship.
Penton-Voak et al. [203] also found that women
preferred slightly more masculine faces in the context
of a short-term relationship than in the context of a
long-term relationship, and that this pattern was exag-
gerated in the least attractive participants (i.e. women
with high waist hip ratios or low other-rated facial
attractiveness). One potential explanation for this
pattern of preference is that attractive women are
better able to compete for, retain or replace high-
quality, masculine partners and, therefore, do not
show as large a shift in their preferences between
short-term and long-term contexts. Indeed, several
studies have shown that more attractive women show
stronger preferences for masculine faces and voices
(reviewed above in §3a(ii)).
The effects of temporal context on judgements of
attractiveness are not limited to faces. Women prefer
lower pitched male voices in the context of a short-
term relationship than in the context of a long-term
relationship [143]. This same study also found that
the effect of relationship context was greatest when
women were in the fertile phase of the menstrual
cycle, a finding that is consistent with research on
cyclic shifts in preferences for facial masculinity [138].
(iii) Environmental context
A strong theoretical prediction of the trade-off account
of variability in women’s preferences for masculine
men is that women in environments where poor
health is particularly harmful to survival (e.g. envir-
onments with high prevalence of pathogens
and inaccessible or poor healthcare) will demonstrate
stronger preferences for cues of health [25,83,92,93,
138,200202]. Regional differences in pathogen preva-
lence have been shown to be positively correlated with
the importance placed on physical beauty and health
DeBruine et al. [206] investigated the relationship
between environmental cues of the importance of
health and women’s preferences for masculinity in a
sample of 30 countries. Health statistics from the
World Health Organization were used to compute a
‘national health index’ (NHI), which was negatively
correlated (r¼20.62) with women’s average masculin-
ity preferences for each country. This relationship
remained significant, even when controlling for regional
variation in wealth and women’s mating strategies (i.e.
whether women tended to pursue more short-term or
long-term relationships; [207]).
Brooks et al. [208] have re-analysed these data and
suggested that regional variation in women’s masculin-
ity preferences may be better explained by regional
variation in male male violence. Masculine-faced
men may be favoured under such conditions, for
example, as they may be better able to compete for
resources. A further study of US states, in contrast,
has shown that environmental health factors, and not
indices of male male violence such as homicide
rates, predicts regional variation in women’s masculin-
ity preferences [209]. Health, wealth and malemale
violence are, of course, inter-related. While it
is ultimately possible that health, wealth and male
male violence may all individually contribute to
variation in preference, it is important to note that
all of these analyses show that regional variation in
women’s masculinity preferences occurs in ways that
are highly consistent with trade-off theories of sexual
The availability of resources in an environment may
also influence face preferences. In low-resource
environments, the resources to raise a child may be
scarce or difficult to acquire and a preference for an
investing partner be adaptive. In contrast, in higher
resource environments, there may be little gain in
terms of offspring survival and reproduction by the
additional effort of a second parent and a preference
for ‘good genes’ may be a better strategy [210,211].
o test these ideas, Little et al. [212] tested men’s
and women’s preferences for masculinity/femininity
in two contexts: a harsh environment with few
resources and a safe environment with plentiful
resources. Both men and women decreased their
preferences for high quality mates for long-term
relationships in the context of a harsh environment.
For example, women were relatively more attracted
to feminine faced men for long-term relationships in
low resource environments, suggesting that women
value potential investment from these men more than
the higher dominance/health of masculine faced men
under these conditions. This is consistent with the
logic of trading genetic quality for commitment and
investment in environments where resources are scarce.
(c)Visual experience
Individuals are confronted with a myriad of faces and
social interactions every day. Research has shown that
such experience leads to changes in preferences for
faces. In the following section, we discuss two aspects
of visual experience examining: (i) how exposure can
impact on preferences and (ii) how observing the
choices of others may affect our preferences.
(i) Exposure
Familiarity is a powerful determinant of attraction.
For many types of stimuli, including faces, exposure
Review. Facial attractiveness A. C. Little et al. 1649
Phil. Trans. R. Soc. B (2011)
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increases attraction even when the exposure is un-
conscious [213215]. Structural features of the face
must be stored and represented in order to determine
familiarity. As noted earlier, one idea for why average-
ness in faces is attractive comes from a link with
familiarity—as average faces appear familiar this
could positively affect their attractiveness [60,62].
Familiarity, when not paired with aversive stimuli, is
thought to be rewarding [214], and indeed there are
obvious benefits to avoiding the unfamiliar. This can
then help explain why exposure may cause increases in
preference. There may, however, be more to increasing
face preference than simple exposure. For example,
recent studies have demonstrated that the nature of
association (positive or negative) can affect face prefer-
ences, with positive experiences leading to increased
attraction and negative experiences to decreased attrac-
tion [216]. Moreover, these effects of valenced exposure
are not bound solely to the specific individuals who were
encountered and generalize to judgements of novel,
physically similar individuals [216].
Familiarity with parental traits has been implicated
in human preferences. The phenomenon of imprint-
ing, whereby individuals are attracted to parental
traits, is well-studied in non-human animals [217,218]
and there is increasing evidence for similar effects in
humans. Following studies of facial similarity, judges
have been shown to correctly match wives to their
mother-in-law at a significantly higher rate than
expected by chance and that wife mother-in-law
similarity is higher than similarity between husbands
and their wives [219]. Such effects are also seen in
adopted daughters, controlling for any potential
genetic effects, with significant facial resemblance
between daughter’s husband and her adoptive father
[220]. Other studies have shown that, for hair and
eye colour, the best predictors of partner traits are
the opposite-sex parent’s colour traits [128] and that
individuals are attracted to age in faces consistent
with the age of their parents when they were born
[221]. It is worth noting that at least in one study,
effects were seen mainly for the opposite-sex parent
[128], which may indicate a more complex mechanism
than simple exposure. Another line of argument
suggesting imprinting-like effects appear not simply
to reflect exposure comes from studies that have
shown effects to be dependent on the quality of the
relationship to the parent [220,222]. For example,
daughters who report that they received greater
emotional support from their adoptive fathers are
more likely to choose mates who are similar to their
father than individuals who report their father
provided less emotional support [220]. Similarly,
women who rate their childhood relationships with
their father positively show stronger attraction to face
proportions similar to their father’s face than women
who rate their relationships less well [222]. Imprint-
ing-like effects then appear more complicated than
simple exposure being directed more to one parent
than the other and showing dependence on the
relationship with that parent.
Imprinting-like effects may lead to positive assorta-
tive mating (pairing with similar partners), at least for
long-term relationships, and this may have benefits in
terms of keeping adaptive suites of genes together
[223] or increasing behaviour compatibility [224].
There is certainly evidence that couples resemble
each other facially [225,226]. While there are costs
to inbreeding, as discussed earlier, a certain amount
of genetic similarity can be beneficial—so-called
‘optimal-outbreeding’ [227]. Potentially then, a system
that learns about known individuals and increases
attraction to their face traits could be adaptive.
Both familiarity and imprinting posit that exposure
affects attractiveness. In recent years, exposure has
been thought to have specific effects on our represen-
tations of faces via visual adaptation. We are unlikely to
have an inbuilt average face and what is average must
be calculated from experience. For each class of
stimuli, the human visual system encounters may
develop an individual representation, or prototype,
made up of an average of the characteristics of all the
different stimuli of that type that have been seen
[228232]. Computer modelling has revealed that
algorithms trained to discriminate different stimuli
produce stronger responses to stimuli that represent
the average of the training set, even though this average
was not previously encountered [228,230]. These
findings have been interpreted as evidence that proto-
type formation is a property of learning to recognize
different stimuli as members of a class [228,230].
Studies on category learning have a long history
(e.g. [233]). Learning studies examine how categorical
perception develops using abstract stimuli. In classic
studies, it has been shown that exposure to different
dot patterns with particular configurations results in
abstraction so that the average of each of the patterns,
while never previously seen, is recognized as belonging
to the set of patterns from which it was derived [233].
Faces have been the focus of much research regard-
ing recognition and prototype formation. While it has
been proposed that faces may be coded as veridical
representations of individuals or exemplars [232],
recent neuroimaging and single-cell recording studies
have supported a prototype-referenced model of face
coding [229,231]. Exposure to faces biases subsequent
perceptions of novel faces, causing faces similar to
those initially viewed to appear more prototypical
than they would otherwise be perceived as, pre-
sumably, a prototype or population of exemplars
becomes updated [234239]. For example, adap-
tation to faces with contracted features causes novel
faces with contracted features to be perceived as
more normal than prior to this exposure [235,239,
240]. Analogous visual after-effects have been ob-
served following exposure to faces varying in identity
[234,236], ethnicity [237], sex [235,237,241], ex-
pression [237], mouth shapes associated with different
spoken sounds [242] and masculinity/femininity
[192,243]. Such after-effects are thought to reflect
changes in the responses of neural mechanisms
underlying face processing [235,238 240].
These studies may then shed light on how the brain
builds an average representation to which the other
faces can be compared. Importantly, exposure in
the manner described above also influences attractive-
ness judgements. After exposure to faces possessing
certain traits, these traits come to be preferred
1650 A. C. Little et al. Review. Facial attractiveness
Phil. Trans. R. Soc. B (2011)
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[192,240,243,244]. For example, if exposed to faces
that look more like one identity, then new faces that
resemble that identity are found more attractive than
if exposed to the opposite set of face traits. A similar
effect has also been observed for judgements of the
trustworthiness of faces [192]. Adaptation then
reflects the rapid updating of face norms and can
therefore be tied both to the effects of familiarity and
imprinting-like effects.
(ii) Social learning
We have dealt briefly with some aspects of simple
experience on preferences above, but, of course,
humans are highly social and much human experience
is of what other humans do. Humans can therefore
learn about attractiveness from the behaviour of
those around them: social learning of preference. We
have recently reviewed social learning in human face
preferences [245], and so present a brief overview here.
Individuals often learn from others and selection for
social learning mechanisms may occur when there are
costs to acquiring accurate behavioural information via
individual learning [246]. Social learning can be adapt-
ive if it allows an individual to assess potential mates
more quickly and efficiently than through individual
trial and error or allows an individual to use another’s
expertise. Mate choice copying has been observed
among females in a number of different non-human
species [247250], including fish [251254]andbird
species [255257]. Such studies have generally shown
that when females observe another female (the model)
to be paired with one of the two males (the targets),
they are subsequently more likely to prefer the target
male they had seen paired with the model over the
male that was not paired with the model.
Inspired by work on non-human species, recent
research also suggests that social learning may influence
human mate preferences. While some research has
shown that the presence of wedding rings on men did
not increase women’s preferences for those men [258],
other studies have found that images of men labelled
single [259] and that women rate men as more desirable
when they are shown surrounded by women than when
they are shown alone or with other men [260]. Another
study has shown that women prefer pictures of men that
women who were looking at the face with smiling (i.e.
positive) expressions compared with pictures of men
who had been seen paired with images of women with
neutral (i.e. relatively negative) expressions [261].
Women therefore do appear to mimic the attitude of
other women to particular men.
Alongside partnership status, simple presence, and
expressions of attitude towards the male, the physical
traits of the observed model may also play a role in
the social transmission of preference. Previous studies
have shown that men’s and women’s attractiveness
judgements are influenced by the apparent choice of
attractive members of the same sex. Sigall & Landy
[262] used real individuals to show that positive
characteristics are attributed more frequently to men
who are paired with attractive rather than unattractive
women. In this way, they show that an attractive part-
ner may ‘radiate beauty’. Such a phenomenon suggests
a more sophisticated form of mate-choice copying,
whereby women can use the attractiveness of a partner
that a man can acquire in order to judge the man’s own
attractiveness. Another study using images that were
presented with a fictitious partner has shown that
both men and women find a face paired with an attract-
ive partner to be more attractive than one paired with an
unattractive partner for a long-term but not a short-
term relationship [263]. Effects specific to long-term
preferences in humans suggest that social information
is being used to infer non-physical traits that make a
target a good long-term partner, such as resources
or intelligence, which may be difficult to determine
from physical appearance alone.
Being more or less attractive has important social conse-
quences and people do generally agree on who is and
construct—attractiveness appears to be ingrained in
our biology. While some aspects of face perception
might be innate, other aspects are clearly influenced by
experience; it seems unlikely that individuals are born
with a representation of what a perfect partner looks like.
Structural and other aspects of human facial appear-
ance are linked to preferences (§2). If a trait reliably
advertises some benefit to the perceiver, then we
would expect individuals in a population to find that
trait attractive. It is clear that individual differences in
preferences for some traits will prove adaptive and so
are consistent with evolutionary theory. We document
several potentially adaptive individual differences in
human face preferences as well as other factors that
may lead to variable preferences (§3). Research on
human facial attractiveness has benefited greatly from
an evolutionary/biological perspective, both in terms
of documenting what traits are likely to be important
and in predicting individual variation. Work on facial
attractiveness is also integrative, combining theories
and methods from behavioural ecology, cognition,
cross-cultural research and social psychology.
Anthony Little is supported by a Royal Society University
Research Fellowship.
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