dt C
vers
niv
ersit
2 M
e 2
preferences for facial masculinity (Frost, 1994; Johnston et al.,
thought to be indicator of quality via classic handicap models
(Folstad and Karter, 1992); as testosterone handicaps the
quality is controversial and there are several lines of reason
preferences, potentially shifting priorities between heritable
benefits to offspring and investment (Penton-Voak et al., 1999).
Although peaks in sexual desire and activity have been
reported at different stages across the menstrual cycle (Regan,
Hormones and Behavior 51 (immune system (Kanda et al., 1996) and therefore only high-2001; Penton-Voak and Perrett, 2000; Penton-Voak et al.,
1999), vocal masculinity (Feinberg et al., 2006; Puts, 2005),
videoclips of dominant behavior (Gangestad et al., 2004) and
for taller men (Pawlowski and Jasienska, 2005) that coincide
with the late follicular (i.e., fertile) menstrual cycle phase have
been reported. These changes in preferences for masculine men
are potentially adaptive. Human males bring two factors to a
parenting relationship: investment in their partners and off-
spring and potential heritable benefits (e.g., genes for high-
quality immune systems). Masculinity in males has long been
involved in why it is preferred (Getty, 2002; Thornhill and
Gangestad, 1999).
While masculine faced men are healthier than their feminine
faced counterparts (Rhodes et al., 2003), masculinity in a
partner also carries a cost. Men with masculine faces have
higher circulating testosterone levels (Penton-Voak and Chen,
2004), which are linked to marital instability and lower levels of
attachment in relationships (Booth and Dabbs, 1993; Burnham
et al., 2003). Thus, variation in preferences during the menstrual
cycle may enable women to maximize the benefits of their mateseen when rating for a short-term but not when rating for a long-term relationship. In line with studies showing similar effects for facial sexual
dimorphism, we also show that women prefer greater masculinity when they think themselves attractive than when they think themselves less
attractive. These results indicate that women's preferences for sexual dimorphism in male bodies follow a similar pattern as found for sexual
dimorphism and dominance in other domains and such differences in preference may serve a similar function. Cyclic preferences could influence
women to select partners when most likely to become pregnant that possess traits that may be most likely to maximize their offspring's quality via
attraction to masculinity or serve to help acquire investment via attraction to femininity.
' 2007 Elsevier Inc. All rights reserved.
Keywords: Facial attractiveness; Fertility; Masculinity/femininity; Mate value; Body; Condition dependence; Short/long term
Many studies have demonstrated that women's preferences
for male traits change across the menstrual cycle. Increased
quality males can afford to be masculine (Thornhill and
Gangestad, 1999). The relationship between masculinity andthat women prefer greater masculinity in male bodies at times when theiIn human females cyclic shifts in preference have been documented for odour and physical and behavioral male traits. Women prefer the smell
of dominant males, more masculine male faces and men behaving more dominantly when at peak fertility than at other times in their menstrual
cycle. Here we examine variation in preferences for body sexual dimorphism. Across two studies, both between- and within-participant, we show
r fertility is likely highest, in the follicular phase of their cycle. Shifts werePreferences for masculinity in male bo
Anthony C. Little
a,b,


, Benedic
a
School of Psychology, Uni
b
School of Biological Sciences, U
c
School of Psychology, Univ
Received 21 October 2006; revised 1
Available onlin
Abstract

Corresponding author. School of Psychology, University of Stirling, Stirling,
FK9 4LA, Scotland, UK. Fax: +44 01786 467641.
E-mail address: anthony.little@stir.ac.uk (A.C. Little).
0018-506X/$ - see front matter ' 2007 Elsevier Inc. All rights reserved.
doi:10.1016/j.yhbeh.2007.03.006ies change across the menstrual cycle
. Jones
c
, Robert P. Burriss
a,b
ity of Stirling, Scotland, UK
ersity of Liverpool, England, UK
y of Aberdeen, Scotland, UK
arch 2007; accepted 15 March 2007
4 March 2007
2007) 633–639
www.elsevier.com/locate/yhbeh1996), studies have reported that women with partners may be
more likely to engage in extra-pair sex at peak fertility. Extra-
pair copulation is 2.5 times more likely during the follicular

ndphase than in the luteal phase (Baker and Bellis, 1995). Further
evidence for possible extra-pair behavior comes from studies
showing that women at peak fertility are more likely to have
sexual fantasies about men other than their primary partner
(Gangestad et al., 2002), express a greater interest in attending
social gatherings where they might meet men at peak fertility
(Haselton and Gangestad, 2006) and to report being more
committed to their partners during the luteal phase of the
menstrual cycle and less committed in the late follicular phase
(Jones et al., 2005). These studies suggest a possible mechanism
whereby women may maximize their chances of becoming
pregnant with the offspring of males chosen for extra-pair
affairs. Such males may be selected for possessing superior or
alternative genes to the woman's current partner.
As an alternative, or perhaps complementary, explanation for
shifting preferences, findings demonstrating the role of changes
in progesterone level for increased commitment to partners and
increased preferences for both feminine faced men and women
during the luteal phase of the menstrual cycle may increase the
care and support that is available during hormonal profiles
similar to those that characterize pregnancy (Jones et al., 2005).
In this way, rather than acquiring direct benefits for offspring
from masculine men, women instead maximize investment
from feminine men (Jones et al., 2005).
Preferences for masculinity in faces have also been found to
be moderated by other factors relating to potentially strategic
choice. Condition-dependent mate choice is seen in female fish
species (Bakker et al., 1999) and humans (Little et al., 2001;
Penton-Voak et al., 2003). Attractive women, possibly due to
their increased competitiveness for mates, are more discriminat-
ing than less attractive women, displaying greater preferences
for masculinity in faces (Little et al., 2001; Penton-Voak et al.,
2003). For short-term relationships, women are more likely to
choose an attractive male who is less cooperative and appears to
have poorer parenting qualities over a less attractive male who
is more cooperative and with better parenting qualities (Scheib,
2001). By contrast, for long-term contexts women may choose
the less attractive but more cooperative man more often (Scheib,
2001). In face preference tasks, women judging for short-term
relationships prefer more masculinity in faces than those
judging for long-term relationships (Little et al., 2002).
Women also prefer to select taller partners for short-term than
for long-term relationships (Pawlowski and Jasienska, 2005). It
is possible that some women may choose a long-term partner
whose feminine appearance suggests cooperation and extended
paternal care and/or choose short-term partners whose higher
facial masculinity may indicate better genetic quality (Little
et al., 2002; Perrett et al., 1998). Already having a partner has
also been shown to predict female face preferences. An
increased preference for genetic fitness over signs of parental
investment would be expected in extra-pair copulations when a
woman has already acquired a long-term partner. Indeed, Little
et al. (2002) have shown that women who have partners prefer
masculinity in faces more than those without a partner.
634 A.C. Little et al. / Hormones aGiven the many effects of menstrual cycle on masculinity
preferences, the current study examined preferences for sexual
dimorphism in body shape across the cycle. Preferences formale body shape have generally used line drawings which have
manipulated specific aspects of shape. Such studies have
revealed preferences for broad shoulders (Dixson et al., 2003),
taller men, particularly at high fertility (Pawlowski and
Jasienska, 2005), masculine (low) waist to chest ratios, broad
shoulders relative to small waist (Maisey et al., 1999) and
masculine (high) waist to hip ratios (WHR) (Dixson et al., 2003;
Singh, 1995). WHR is sexually dimorphic, with women tending
towards a lower ratio during their fertile years that typifies the
hourglass figure. Men tend to have more similar waist and hip
measurements, resulting in a less curvy appearance. This occurs
because testosterone stimulates fat deposits in the abdominal
region while inhibiting fat deposits in the buttocks and thighs
(Rebuffescrive, 1987). The current study uses realistic male
images manipulated with computer graphic techniques for
global sexual dimorphism using methods adapted from those
used in many studies of preferences for masculinity in faces
(Little et al., 2001; Little and Hancock, 2002; Little et al., 2002;
Penton-Voak et al., 1999; Perrett et al., 1998). By using the
difference between male and female bodies, the resulting
images differ in the average way that men differ from women in
shape and encompass general aspects of masculine shape
(controlling for height differences). The current study focused
on whether preferences for sexual dimorphism in shape change
across the menstrual cycle following studies demonstrating that
preferences for masculinity in face shape and height also
change. We also examine other variables known to influence
preferences for masculinity in faces: temporal context (short vs.
long term), partnership status and condition-dependent prefer-
ences. For condition-dependent preferences we used self-
perceived attractiveness as a proxy for mate-value/condition
following previous studies (Little et al., 2001).
We predicted, following similar results for preferences for
masculinity in male faces, that women would prefer more
masculine male bodies when in the follicular phase of their
cycle and that preferences for masculinity would be enhanced
for short-term relationships. We also predicted that menstrual
cycle shifts may be greater for short-term relationships, again
following findings from face preferences. In Study 1 where we
examined self-perceived attractiveness we expected that women
viewing themselves as more attractive would have enhanced
preferences for masculinity. We also included a separate
analysis of women who reported using hormonal contraception.
These participants represent a control group and were not
expected to show menstrual cycle shifts in preference.
Methods
Study 1
Participants
Ninety-seven female participants (aged 17–35, mean age=24.9, SD=5.5)
took part in the study. The study was administered over the internet via a link
from www.alittlelab.com and participants were volunteers selected for reporting
to be heterosexual, not using oral or other hormonal contraception, being
between 17 and 35 years of age, not being pregnant and having a restricted range
Behavior 51 (2007) 633–639in their reported cycle date (days since menstruating reported as 0–28, 61 were
classified low fertile and 36 high fertile, see classification below). Sixty-one
women (aged 17–35, mean age=24.9, SD=5.4) who reported using hormonal