The Science of Sex Appeal: An Evolutionary Perspective
Gordon G. Gallup, Jr.
University at Albany, State University of New York
David A. Frederick
University of California at Los Angeles
Growing evidence shows that features we find attractive in members of the opposite sex signal important
underlying dimensions of health and reproductive viability. It has been discovered that men with
attractive faces have higher quality sperm, women with attractive bodies are more fertile, men and
women with attractive voices lose their virginity sooner, men who spend more money than they earn have
more sex partners, and lap dancers make more tips when they are in the fertile phase of their menstrual
cycle. This paper highlights recent evidence showing that the way we perceive other people has been
shaped by our evolutionary history. An evolutionary approach provides a powerful tool for understanding
the consistency and diversity of mating preferences and behaviors across individuals and cultures.
Keywords: evolutionary psychology, facial attractiveness, body configuration, voice, menstrual cycle,
muscularity, body fat, dishonest signals
A cursory glance at the women featured in popular men’s
magazines, such as Maxim or Playboy, suggests that men are
attracted to young women with smooth skin, long soft hair, large
eyes, slender bodies, long legs, curved hips, large pronounced
breasts, rounded buttocks, and flat stomachs (Spitzer, Henderson,
& Zivian, 1999; Voracek & Fisher, 2002). In contrast, a reader
glancing through Cosmopolitan would conclude that women are
attracted to tall athletic men with moderately muscular arms and
legs, broad shoulders, little body fat, square and powerful-looking
jaws, and toned abdominal muscles (e.g., Frederick, Fessler, &
Haselton, 2005). Notably, however, some body types are rarely
represented. Women’s magazines almost never feature men who
are very short, elderly, and fat, with wrinkly skin, open sores and
wounds, and mouths with stained and missing teeth.
The pressure to be attractive can leave many people feeling
dissatisfied with their appearance (Peplau et al., 2009; Frederick,
Forbes, Grigorian, & Jarcho, 2007), and across cultures and his-
tory, men and women have devised a wide variety of techniques to
enhance their attractiveness (Etcoff, 1999). Corsets give women
the appearance of narrower waists relative to their hips and modern
gyms allow men to enhance their muscularity and shoulder width.
Cosmetic surgery enables women to create the appearance of
youthful faces, large shapely symmetrical breasts, narrow waists
larger buttocks, and more symmetrical faces. Human growth hor-
mone and steroids enable people to grow taller and stronger.
Cosmetics, such as make-up, enable people to cover blotches,
wrinkles, and imperfections in the skin.
Why do so many people spend so much time, effort, and money
on their appearance? Why do we find some people more attractive
than others? If beauty is only skin deep, why should it matter how
people look? What follows is a review of the science of sex appeal,
targeting recent findings that illustrate the conceptual and heuristic
value of an evolutionary perspective.
1
We first briefly outline how
evolution shapes the way we process information about other
people, and then focus on why we find certain faces, body types,
and voices appealing. We show how an evolutionary perspective
enables us to understand and predict ways that women’s prefer-
ences for some of these traits shift across the menstrual cycle. We
conclude with a discussion of how individuals have developed
cultural and technological innovations to enhance certain aspects
of their appearance.
The Impact of Evolution
It is important to understand that we do not experience the world
or other people directly. Rather, our experience is a byproduct of
sensory input acting on the nervous system. Our sensory receptors
are evolved neurological mechanisms that convert mechanical,
chemical, thermal, or electromagnetic energy into nerve impulses.
These nerve impulses in turn activate evolved parts of the brain
that translate these impulses into experience.
The age-old question, “if a tree fell over in the woods and no one
was there to hear it, would it make a noise?” has a clear and
definitive answer from a neurobiological perspective. No doubt a
felled tree would produce intense air borne vibrations, but in order
to be “heard” or to make a “noise” these vibrations would have to
impinge on an ear and trigger nerve impulses that activate relevant
1
In biological terms, traits that are more typical of women are consid-
ered “feminine” whereas traits that are more typical of males are consid-
ered “masculine.” For example, testosterone “masculinizes” men’s faces
by making their jaws squarer, and estrogen “feminizes” women’s faces by
making their jaws more rounded.
Gordon G. Gallup, Jr., University at Albany, State University of New
York; David A. Frederick, Department of Psychology, University of Cal-
ifornia at Los Angeles; FPR-UCLA Center for Culture, Brain, and Devel-
opment; and UCLA Center for Behavior, Evolution, and Culture.
We thank Kelly Carrone, Melissa Fales, Andrew Galperin, Kelly Gild-
ersleeve, Martie Haselton, Susan Hughes, Christina Larson, Matthew Pas-
tizzo, Loni Petricone, and Nathan Pipitone for helpful comments on pre-
vious drafts of this paper.
Correspondence concerning this article should be addressed to Gordon
G. Gallup, Jr., Department of Psychology, University at Albany, State
University of New York, Albany, NY 12222. E-mail: gallup@albany.edu;
or David A. Frederick, 3rd Floor Mailroom, 1285 Franz Hall, 405 Hilgard
Ave, University of California, Los Angeles, CA 90095. E-mail:
enderflies1@aol.com
Review of General Psychology © 2010 American Psychological Association
2010, Vol. 14, No. 3, 240–250 1089-2680/10/$12.00 DOI: 10.1037/a0020451
240

parts of the auditory cortex. Although we take sound for granted,
sound is not an inherent feature of the world. Sounds only exist in
your head.
Why is sugar sweet? Contrary to the impression it creates when
placed on your tongue, sweet is not an inherent property of sugar.
Just like sound, the experience of sweet is an evolved property of
the nervous system (Barash, 1979). Sugar is a good source of
calories. Organisms that developed receptors and neurological
mechanisms that enabled them to experience foods containing
sugar as sweet/pleasant had an adaptive advantage in being able to
identify and preferentially exploit food sources that were rich in
calories. For similar reasons, if vultures, hyenas, and other carrion
eaters could talk, they would be the first to tell you that foul odor
is not an inherent property of rotting flesh.
Why is being kicked in the groin an excruciatingly painful
experience for men? Unlike women whose gonads are embedded
deep inside the body, testicles migrate down through the body
cavity during embryonic development and usually wind up outside
the body in a thin, unprotected scrotal sack. As a consequence,
descended testicles are inherently more vulnerable than ovaries.
Males with descended testicles were selected during the course of
evolution to develop receptors and neural mechanisms that medi-
ate the experience of pain in response to testicular insults, which in
turn prompts each successive generation of males to 1) learn to
avoid situations that put the testicles at risk, and 2) refrain from
engaging in behaviors that might endanger the testicles. In other
words, men have evolved to behave in ways that maintain the
integrity of the testicles and this effect is mediated in part by
heightened sensitivity to testicular pain (Gallup, Finn, & Sammis,
2009).
All of these examples are linked by a common theme. When
there were recurrent adaptive problems, organisms that evolved
solutions to these problems had genes that became better repre-
sented in future generations. Evolutionary psychologists hypothe-
size that many such evolved systems exist and that these systems
respond flexibly in response to changing environmental inputs,
ecologies, and internal states (e.g., Barrett & Kurzban, 2006;
Pinker, 2002). Many of these systems serve clear adaptive func-
tions, such as entering puberty earlier or later depending on
whether ecological conditions are harsh or stable, rapidly acquiring
fears of snakes and dangerous predators, generating language for
the purposes of communication, seeking out food when calorie
stores run low, and recognizing who is a kin member and discour-
aging incest with close genetic relatives (for an overarching sum-
mary see Buss, 2005).
What follows is a representative review of sex appeal designed
to target recent findings that illustrate the value of an evolutionary
perspective.
Attractive Faces
Many people think facial attractiveness is a byproduct of
experience and cultural influences. According to this view
attractive faces and sex appeal are learned social constructions
(see DeLamater & Hyde, 1998). Are attractive features simply
a byproduct of how people are educated and raised?
Our perception of faces often prevails in spite of our experience.
Growing evidence shows that how people rate faces is largely
independent of their gender, culture, ethnic group status, sexual
orientation, and age (see Thornhill & Gangestad, 1999). There is a
high degree of cross-cultural consensus about which faces are
attractive. Not only do Caucasians rate Asian faces much the same
way Asians do, but the same is true for the way Asians rate
Caucasian faces (Cunningham Roberts, Barbee, Druen, & Wu,
1995; for a meta-analysis see Langlois et al., 2000). Even neonates
without the benefit of prior experience or socialization spend more
time looking at photos of faces that adults find attractive (Ramsey,
Langlois, Hoss, Rubenstein, & Griffin, 2004).
Recent discoveries show surprising links between faces and
underlying differences in health, vitality, and fertility. By sampling
photographs taken from old high school yearbooks and matching
them with obituary records, Henderson and Anglin (2003) discov-
ered that both men and women with faces that contemporary
college students rated as being attractive lived longer. Researchers
are currently attempting to isolate the degree to which facial
attractiveness is linked to health, which aspects of health it relates
to, and how consistent the link is (Weeden & Sabini, 2005;
Rhodes, 2006; Thornhill & Gangestad, 2006).
Faces also contain cues to fertility. Soler et al. (2003) took facial
photos and semen samples from male college students. The semen
samples were assayed for sperm count, sperm motility, and sperm
morphology to generate a composite index of sperm quality. A
number of women who did not know these men were asked to rate
the photos for attractiveness. The researchers discovered that how
the women rated the men’s faces were correlated with the semen
assay results. Men with faces that women found attractive tended
to have significantly more fertile, higher quality sperm. There are
several intriguing explanations for this pattern. Attractive men may
garner more interest from women, which may boost their testos-
terone and sperm production, or men who are generally more
robust and healthy overall may have more attractive faces and
enhanced ability to produce sperm.
Even intelligence and semen quality may be related. In an
archival sample of 425 Army veterans, Arden, Gottfredson, Miller,
& Pierce (2009) found small, but significant positive correlations
between general intelligence and several important parameters of
sperm quality: sperm concentration, sperm count, and sperm mo-
tility. It turns out that people with attractive faces also tend to have
higher IQ scores (Zebrowitz, Hall, Murphy, & Rhodes, 2002).
The way men rate facial attractiveness in women predicts es-
trogen levels and female reproductive health (Law-Smith et al.,
2006). Faces can contain cues to underlying genetic resistance to
disease. The Major Histocompatibility Complex is an important set
of genes that help code for the development of the immune system.
Being heterozygous at this loci—that is, having copies of different
alleles (genes) rather than having multiple copies of the same
alleles—provides resistance to a wider variety of potential para-
sites and threats to the immune system. Consistent with an evolu-
tionary perspective, men who are heterozygotic at the Major His-
tocompatibility Complex are judged by women as being more
attractive (Roberts et al., 2005). Both men and women with at-
tractive faces also show fewer subtle morphological deviations
from bilateral symmetry, which is a ubiquitous measure of health
and fitness (Grammer & Thornhill, 1994).
A person’s face even conveys information about their body and
their behavior. Given the potential dangers of failing to detect a
physically powerful rival, Sell et al. (2009) reasoned that individ-
uals would be able to accurately gauge a person’s strength based
241EVOLUTION OF SEX APPEAL