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Why Can’t a Man Be More Like a Woman? Sex Differences in Big Five
Personality Traits Across 55 Cultures
David P. Schmitt
University of Tartu and The Estonian Centre of Behavioural and
University of Vienna
University of Tartu and The Estonian Centre of Behavioural and
Previous research suggested that sex differences in personality traits are larger in prosperous, healthy, and
egalitarian cultures in which women have more opportunities equal with those of men. In this article, the
authors report cross-cultural findings in which this unintuitive result was replicated across samples from
55 nations (N⫽17,637). On responses to the Big Five Inventory, women reported higher levels of
neuroticism, extraversion, agreeableness, and conscientiousness than did men across most nations. These
findings converge with previous studies in which different Big Five measures and more limited samples
of nations were used. Overall, higher levels of human development—including long and healthy life,
equal access to knowledge and education, and economic wealth—were the main nation-level predictors
of larger sex differences in personality. Changes in men’s personality traits appeared to be the primary
cause of sex difference variation across cultures. It is proposed that heightened levels of sexual
dimorphism result from personality traits of men and women being less constrained and more able to
naturally diverge in developed nations. In less fortunate social and economic conditions, innate person-
ality differences between men and women may be attenuated.
Keywords: sex differences, personality traits, culture
Why can’t a woman be more like a man?
—Alan Jay Lerner, My Fair Lady
In many studies, including several meta-analytic investigations,
it has been found that men tend to be more assertive and risk taking
than women, whereas women are generally higher than men in
anxiety and tender-mindedness (Brody & Hall, 2000; Byrnes,
Miller, & Schafer, 1999; Feingold, 1994; Kring & Gordon, 1998;
Lynn & Martin, 1997; Maccoby & Jacklin, 1974). These sex
differences in personality traits can be detected in early childhood
(Else-Quest, Hyde, Goldsmith, & Van Hulle, 2006; Wilgenbusch
& Merrell, 1999) and remain fairly constant across adulthood
(Feingold, 1994; McCrae & Costa, 1984). The effects of these sex
differences lead to predictable differences in men’s and women’s
leisure behaviors, occupational preferences, and health-related out-
comes (Browne, 1998; Collaer & Hines, 1995; Lippa, 2005).
Although sex differences in personality traits are not as large as
sex differences in mate preferences, permissive sexual behaviors,
or physical strength (Feingold, 1992; Schmitt, 2005b; Thomas &
French, 1985), sex differences in personality traits do appear to be
larger and more robust than sex differences in other domains such
as cognitive ability, attributional style, and self-esteem (Else-Quest
et al., 2006; Hyde, 2005).
Observed sex differences in personality traits such as asser-
tiveness and anxiety also appear to be culturally pervasive
(Costa, Terracciano, & McCrae, 2001; Lynn & Martin, 1997).
Feingold (1994) found that women in Canada, China, Finland,
Germany, Poland, and Russia tended to score higher than men
on scales related to the personality traits of neuroticism, agree-
ableness, and conscientiousness. Men, in contrast, scored
higher in the extraversion-related trait of assertiveness across
cultures. In a much larger study, self-report responses to the
Revised NEO Personality Inventory (NEO-PI-R) across 36 cul-
tures revealed that women in most countries are higher in
several traits related to neuroticism, agreeableness, warmth, and
openness to feelings, whereas men score higher on scales mea-
suring assertiveness and openness to ideas (Costa et al., 2001;
David P. Schmitt, Department of Psychology, Bradley University; Anu
Realo and Ju¨ri Allik, Department of Psychology, University of Tartu,
Tartu, Estonia, and The Estonian Centre of Behavioural and Health Sci-
ences, Tartu, Estonia; Martin Voracek, Department of Psychology, Uni-
versity of Vienna, Vienna, Austria.
The writing of this article was supported by Grants 6797 and 5677 from
the Estonian Science Foundation and by Estonian Ministry of Science and
Education Grant 0182585s03 to Anu Realo and Ju¨ri Allik. We thank
Toomas Tammaru and Peeter Ho˜rak for valuable comments and sugges-
Correspondence concerning this article should be addressed to David P.
Schmitt, Department of Psychology, Bradley University, 105 Comstock
Hall, Peoria, IL 62625, or to Ju¨ri Allik, Department of Psychology,
University of Tartu, Tiigi 78, Tartu 50410, Estonia. E-mail:
firstname.lastname@example.org or email@example.com
Journal of Personality and Social Psychology Copyright 2008 by the American Psychological Association
2008, Vol. 94, No. 1, 168–182 0022-3514/08/$12.00 DOI: 10.1037/0022-35188.8.131.52
Many of these sex differences in personality traits appear to
transcend data sources (e.g., Williams & Best, 1990). In a large
study of 50 cultures, college students were asked to identify an
adult or a college-aged man or woman whom they knew well and
to rate that person’s personality traits, again using the NEO-PI-R
(McCrae, Terracciano, & 78 Members of the Personality Profiles
of Cultures Project, 2005). Men were rated by observers as being
higher than women in assertiveness, excitement seeking, and open-
ness to ideas. Women were rated by observers as being higher on
many traits, especially in anxiety, vulnerability, aesthetics, feel-
ings, and tender-mindedness (McCrae et al., 2005). Thus, sex
differences in personality traits seem to be rather robust, persisting
across a diverse array of measures, data sources, ages, and cul-
Cultural Variability in the Size of Sex Differences in
Sex differences in most personality traits, however, are not
uniform in magnitude across all samples. At times, sex differences
can be much larger in some cultures than in others (Fischer &
Manstead, 2000; Guimond et al., 2007; Schwartz & Rubel, 2005).
One unexpected finding has been that sex differences in person-
ality traits are often larger in prosperous, healthy, and egalitarian
cultures in which women have more opportunities equal with men
(Costa et al., 2001; McCrae, 2002). Both in self-report and in
other-report data, Asian and African cultures generally show the
smallest sex differences, whereas European and American cul-
tures—in which living standard and gender equity indexes are
generally higher—show the largest differences (McCrae et al.,
2005). With improved national wealth and equality of the sexes, it
seems differences between men and women in personality traits do
not diminish. On the contrary, the differences become conspicu-
It might seem intuitive to think that the more prosperous and
egalitarian a society, the more free men and women are to be
similar in terms of their personality profiles. This logic appears
useful for explaining certain value priorities and sexual strategies
pursued by men and women. For instance, Schwartz and Rubel
(2005) found that sex differences in the value of self-direction are
smaller in richer countries with more individualist and autonomous
values than in poorer countries with more collectivist and embed-
ded cultures. Similarly, Schmitt (2005b) found that sex differences
in sociosexual orientation are smaller (though still moderate in
magnitude) in countries with higher levels of prosperity and sexual
equality. The finding that sex differences in personality traits are
larger in rich and egalitarian cultures may therefore be somewhat
counterintuitive and is certainly contrary to other established pat-
terns of sexual differentiation across cultures. It is important to
note that understanding this intriguing cross-cultural pattern might
be particularly informative for discerning the ultimate origins of
Explaining Cultural Variability in the Size of Sex
Differences in Personality
Several theoretical approaches would appear useful in explain-
ing cultural variability in the size of sex differences in personality.
In general, these approaches are founded on the same group of
theories used to explain the basic origins of psychological sex
1. Social Role Explanations
A leading candidate for explaining variations in the size of sex
differences across cultures is the social role model approach.
According to this approach, most sex differences are assumed to
result from exposure to sex role socialization, a process whereby
culture defines the appropriate ways of thinking, feeling, and
behaving for men and women (Eagly, 1987; Ruble & Martin,
1998; though see Maccoby, 2000).
Because specified male and female roles are thought to contrib-
ute directly to all observed psychological differences between men
and women, including personality traits, it is expected that when
men and women occupy social roles that are more similar, sex
differences will tend to erode (Eagly & Wood, 1999; Wood &
Eagly, 2002). Thus, the social role model approach predicts that
sex differences in personality traits will be attenuated in more
progressive and gender egalitarian cultures and will be accentuated
in more traditional cultures.
2. Evolutionary Explanations
Evolutionary approaches consider sex-related differences as
arising, in part, from innate dispositional differences between the
sexes (Baron-Cohen, 2003; Buss, 1997; Geary, 1998). In this view,
the sexes are thought to psychologically differ only in domains in
which they have faced different adaptive problems throughout
evolutionary history. As a consequence, much of the sex-related
differences that appear in modern societies may be due to sexual
selection pressures that shaped psychological sex differences in the
evolutionary past (Buss & Kenrick, 1998; Mealey, 2000).
Sex differences in levels of obligatory parental investment (Sy-
mons, 1979; Trivers, 1972) are thought to have led to sexual
selection pressures causing men to be more prone to take risks and
to seek social dominance (which benefits the lesser-investing
parental sex in a species), whereas women are thought to have
been selected to be more cautious and nurturing (which benefits
the heavier-investing parental sex; Buss, 1997; Campbell, 2002;
MacDonald, 1995). Although evolutionary explanations can
readily account for the existence of culturally pervasive differ-
ences between men and women, such explanations may seem less
adept at explaining the variability in the size of sex differences
across cultures (though see Buss, 2001; Gangestad, Haselton, &
Buss, 2006; Gangestad & Simpson, 2000).
One evolutionary approach that directly addresses cultural vari-
ability is the mismatch perspective (Crawford, 1998; Nesse &
Williams, 1994). Evolutionary mismatch theories explain psycho-
logical variations across cultures by the degree of mismatch be-
tween contemporary environmental conditions and those in which
early humans evolved—namely, hunter-gatherer environments
(Brown, 1991; Tooby & DeVore, 1987). When contemporary
environments are different from hunter-gatherer environments, the
adaptive development of innate psychological sex differences can
Mismatches between ancestral conditions in which sex differ-
ences in personality evolved and contemporary environments
might at first glance appear largest in the most modern and
SEX DIFFERENCES, PERSONALITY, AND CULTURE
industrialized nation-states. However, this may not be the case
(Pasternak, Ember, & Ember, 1997). Schmitt (2005a) has argued
that the psychological mismatch between contemporary environ-
ments and those in which early humans evolved is not always a
linear function of sociohistorical time. For example, according to
the curvilinear hypothesis of cultural variation (Schmitt, 2005a),
modern nation-states may be psychologically closer to hunter-
gatherer cultures than are less-developed agricultural or pastoral
cultures (Lee & Daly, 1999). Agricultural and pastoral cultures,
with extremely large disparities in resource distribution, familial
isolation, and relative gender inequality, may represent the largest
psychological deviations from our hunter-gatherer past (Korotayev
& Kazankov, 2003; Lamb & Hewlett, 2005). Over sociohistorical
time, therefore, our most modern postagricultural environments
may be gradually becoming more similar to, not more different
from, the hunter-gatherer psychological conditions in which sex
differences in personality traits evolved.
3. Artifact Explanations
A third type of explanation assumes that observed sex differ-
ences in personality are caused by forms of measurement error. For
example, it is possible that social desirability biases lead men and
women to endorse particular gender-relevant traits at different
levels. In some cultures, certain traits (such as fearfulness) may be
less undesirable for women to endorse than for men. Observed sex
differences, in this case, would not reflect actual personality trait
differences and would instead reflect each sex’s comfort in reveal-
ing undesirable personality characteristics. However, the hypoth-
esis that men and women have different social desirability biases
in some cultures is unlikely. For instance, a study of 10 countries
from around the world found strong correlations between men’s
and women’s favorability ratings (Williams, Satterwhite, & Saiz,
Another possibility is that different frames of reference for
self-description are used in different cultures (Guimond et al.,
2007). Costa and his colleagues (Costa, Terracciano, & McCrae,
2001) proposed the following scenario: Self-descriptions in some
cultures (but not others) are based on comparisons of the self with
others of the same gender. For example, when asked whether she
was kind, a traditional woman might rank herself relative to
women she knows, but not relative to men. In that case, sex
differences would be eliminated, just as they are eliminated by the
use of within-sex norms. By contrast, in modern and more egali-
tarian cultures men and women may compare themselves with
others from both sexes and thus reveal true sex differences in
personality. If respondents in traditional cultures were explicitly
instructed to compare themselves with both sexes, larger sex
differences might be found (Costa et al., 2001).
Another artifact explanation of sex differences in personality
traits, which was regarded by Costa et al. (2001) as the most
plausible, relies on different attribution processes. In individualist
and egalitarian cultures, an act of kindness by a woman may be
perceived (by her and by others) as an act of free choice that
directly reflects her personality. The same act by a woman in a
collectivist and traditional culture might be dismissed as mere
compliance with sex role norms. Thus, real sex differences in
social behavior could be objectively seen everywhere but would be
attributed to roles rather than to traits in more traditional cultures.
Thus, in traditional cultures, perceived sex differences between
men and women might be attributed to social role requirements
rather than to intrinsic differences in personality traits (Costa et al.,
Finally, it is plausible that differences in personality traits are
masked by measurement error. One might expect, for example,
that in countries where people are better educated and more
literate, overall internal consistency of personality scales is higher.
In countries where access to education is more restricted, differ-
ences between men and women in personality traits may still exist,
but these differences are attenuated due to a larger response
inconsistency. Indeed, cross-cultural studies have observed that
average Cronbach’s alpha across all personality traits tends to be
higher in prosperous and well-educated countries than in countries
where access to knowledge and education is more constrained
(McCrae et al., 2005).
Ultimately, these competing approaches—social roles, evolu-
tionary psychology, and measurement artifacts—are not mutually
exclusive, and each may explain part of the observed variability in
personality sex differences across cultures.
Basic Aims of the Current Study
The first goal in this study was to replicate the previously
observed sex differences in personality traits. Thus far, there have
been only two studies in which the widening gap between the
personalities of men and women in more modern cultures has been
reported. In both cases, the NEO-PI-R was used, either in self-
report (Costa et al., 2001; McCrae, 2002) or in observer-report
(McCrae et al., 2005) formats. Therefore, it is unknown whether
this observed regularity across cultures is produced by the NEO-
PI-R instrument itself and is not replicated by other personality
measures. Although 36 (McCrae, 2002) and 50 (McCrae et al.,
2005) cultures are large datasets, the selection of cultures in these
studies has been biased toward European nations. Improved at-
tempts to generalize these findings would include more diverse
cultures, especially those from Africa. In the current study, several
new African, Asian, and Middle Eastern samples were included.
The second aim in the current study was to provide evidence
that could constrain the range of possible explanations for the
widening gap between men’s and women’s personality traits in
developed and more egalitarian countries. Obviously, this unre-
solved issue is not due to a lack of theoretical explanations but
instead lies in the absence of decisive evidence that could elimi-
nate less plausible theories. The current study was based on one the
largest cross-cultural studies of personality ever conducted, carried
out as a part of the International Sexuality Description Project
(ISDP; Schmitt & 121 Members of the ISDP, 2003, 2004). The 55
diverse nations of the ISDP allowed us to explore a wide range of
culture-level factors that might influence variability in personality
sex differences across cultures.
The research reported in this article is a result of the ISDP, a
collaborative effort of over 100 social, behavioral, and biological
scientists from 56 nations (Schmitt & 121 Members of the ISDP,
2003, 2004). A detailed description of the methodology and sam-
pling techniques used in the ISDP is given elsewhere (Schmitt &
170 SCHMITT, REALO, VORACEK, AND ALLIK
121 Members of the ISDP, 2003, 2004). Ukrainian data from the
ISDP were eliminated from the current analysis due to poor
translation of the Big Five Inventory (BFI), which resulted in very
low internal reliability values. Thus, 55 ISDP nations constituted
the current set of national samples.
All samples were administered the BFI of personality traits
(Benet-Martı´nez & John, 1998). The 44-item English BFI was
constructed to allow quick and efficient assessment of five per-
sonality dimensions—Neuroticism, Extraversion, Openness to Ex-
perience, Agreeableness, and Conscientiousness—when there is
no possibility or need for more differentiated measurement of
personality facets (Benet-Martı´nez & John, 1998). Self-report rat-
ings are made on a scale from 1 (disagree strongly)to5(agree
strongly) for each of the 44 items. A more detailed description of
the samples and psychometric qualities of the BFI in the ISDP are
given elsewhere (see Schmitt, Allik, McCrae, & Benet-Martı´nez,
Cultural Values Indicators
Inglehart’s value dimensions. The construction of national
scores of the traditional/secular-rational and survival/self-
expression value dimensions were based on a factor analysis of
culture-level data from the World Values Survey as described in
Inglehart and Baker (2000). The actual national scores were re-
ceived from Ronald Inglehart (personal communication, July 23,
2003). Higher scores reflect higher levels of secular-rational or
self-expression values, respectively. People in traditional societies
tend to emphasize the importance of religion, have high levels of
national pride, favor more respect for authority, and value obedi-
ence and conformism. Societies high on secular-rationalism em-
phasize the opposite. Societies that stress survival values are
relatively materialistic. People in those societies report poor health
and low levels of trust and happiness, are relatively intolerant
toward outgroups, show low enthusiasm for and awareness of
environmental protection issues, and are meager in political ac-
tiveness and personal responsibility. Societies high on self-
expression emphasize the opposite (Inglehart & Baker, 2000;
Inglehart, Norris, & Welzel, 2002; Inglehart & Welzel, 2005).
Interpersonal trust and life satisfaction. The interpersonal
trust (percentage of respondents saying most people can be trusted)
and life satisfaction (percentage of people saying that they are
satisfied with their life as a whole these days) scores across the
ISDP nations were based on the 1999 –2002 World Values Survey
(Inglehart, Basanez, Diez-Medrano, Halman, & Luijkx, 2004, Ta-
bles A165 and A170, respectively).
Materialist and postmaterialist values. Materialist and post-
materialist variables measure “the extent to which the respondent
gives top priority to economic and physical security” (i.e., to
materialist values) versus “autonomy and self-expression” (i.e., to
postmaterialist values; Inglehart et al., 2004, p. 410). Percentages
of people supporting materialist or postmaterialist values were
taken from Inglehart et al. (2004, Table Y002).
Hofstede’s value dimensions. Hofstede (1980, 2001), in his
extensive IBM Corporation study of more than 50 countries,
identified four primary cultural dimensions that explained more
than half of cross-cultural variation in work-related values:
individualism– collectivism, power distance, masculinity–
femininity, and uncertainty avoidance. All indices were standard-
ized and were brought into a range between 0 and 100.
Individualism– collectivism refers to the degree to which individ-
uals are integrated into groups (higher individualism– collectivism
scores reflect individualism); power distance is the extent to which
less powerful members of organizations and institutions (like the
family) accept and expect that power is distributed unequally
(higher scores reflect large power distance); masculinity–
femininity describes the extent of emphasis on work goals (earn-
ings, advancement, and assertiveness) as opposed to interpersonal
goals (friendly atmosphere, getting along with the boss) and nur-
turance (higher masculinity–femininity scores reflect masculinity);
and uncertainty avoidance deals with a society’s tolerance for
uncertainty and ambiguity (higher uncertainty avoidance scores
reflect strong uncertainty avoidance). In our study, index scores of
Hofstede’s four cultural dimensions were taken from Hofstede
Gender Equality Indicators
Sex ratio. The number of men for each woman in a total
population represents the sex ratio of a culture. Data on national
sex ratios in 2003 were retrieved from the Central Intelligence
Agency (2006) World Factbook (https://www.cia.gov/library/
Gender Empowerment Measure (GEM). The GEM (United
Nations Development Programme, 2006) is a composite index
measuring gender inequality in three basic dimensions of empow-
erment— economic participation and decision-making, political
participation and decision-making, and power over economic re-
sources. National GEM data for 2003 were taken from http://
Gender-Related Development Index (GDI). The GDI (United
Nations Development Programme, 2006) is a composite index
measuring average achievement in the three basic dimensions
captured in the Human Development Index (HDI; United Nations
Development Programme, 2006)—long and healthy life, knowl-
edge and education, and decent standard of living—adjusted to
account for inequalities in development between men and women.
National GDI scores for 2003 were retrieved from http://
Sex ratios. The percentage of men smoking for each woman in
the total population (World Health Organization, 2004), the latest
data being available from 1995–2004, was obtained from http://
www.heartstats.org/datapage.asp?id ⫽889. The number of male
students for each female student in the total population enrolled in
primary, secondary, and tertiary levels of education, regardless of
age, as a percentage of the population of official school age for the
three levels (United Nations Development Programme, 2006), was
available for 2002–2003 and was retrieved from http://
hdr.undp.org/statistics/data/indicators.cfm. The national ratio of
estimated female earned income to estimated male earned income
for 2003 (United Nations Development Programme, 2006) was
taken from http://hdr.undp.org/statistics/data/indicators.cfm.
Female professional and technical workers. Women’s share
of positions defined according to the International Standard Clas-
sification of Occupations to include physical, mathematical, and
SEX DIFFERENCES, PERSONALITY, AND CULTURE
engineering science professionals (and associate professionals);
life science and health professionals (and associate professionals);
teaching professionals (and associate professionals); and other
professionals and associate professionals for 2003 (United Nations
Development Programme, 2006) were taken from http://
Sex differences in life expectancy. The number of years a
newborn female infant would live longer than a newborn male
infant if prevailing patterns of age-specific mortality rates at the
time of birth were to stay the same throughout the children’s
life for 2003 (United Nations Development Programme, 2006)
were taken from http://hdr.undp.org/statistics/data/indicators
Sex differences in blood pressure. Mean blood pressure of
populations (age-adjusted to the World Health Organization
Standard population, age 15 years and older) expressed in
mmHg (millimeters of mercury, which is a unit of pressure) for
men and women in 2002 (World Health Organization, 2006)
were taken from http://www.who.int/globalatlas/dataQuery/
HDI. The HDI is a composite index measuring average
achievement in three basic dimensions of human development—
having a long and healthy life, having access to knowledge and
education, and enjoying a decent standard of living. The reversed
rank orders of national HDI levels for 2003 (United Nations
Development Programme, 2006) were retrieved from http://
Gross domestic product (GDP) per capita (in US dollars).
GDP converted to U.S. dollars with the average official exchange
rate reported by the International Monetary Fund, divided by the
midyear population, was used in the current study. National levels
of GDP per capita for 2003 (United Nations Development Pro-
gramme, 2006) were retrieved from http://hdr.undp.org/statistics/
School enrollment. The number of students enrolled in pri-
mary, secondary, and tertiary levels of education, regardless of
age, as a percentage of the population of official school age for the
three levels were used in the current study. National school en-
rollment data for 2002–2003 (United Nations Development Pro-
gramme, 2006) were retrieved from http://hdr.undp.org/statistics/
Life expectancy at birth. The number of years a newborn
infant would live if prevailing patterns of age-specific mortality
rates at time of birth were to stay the same throughout the child’s
life was used in the current study. National data for 2003 (World
Health Organization, 2006) were obtained from http://www
Gini index. The Gini index (United Nations Development
Programme, 2006) measures the extent to which the distribution of
income (or consumption) among individuals or households within
a country deviates from a perfectly equal distribution. A value of
0 represents perfect equality; a value of 100 represents maximal
inequality. National Gini indexes for 2003 were retrieved from
Method Quality Indicators
Cronbach’s alpha. Average Cronbach’s alpha across all five
dimensions was computed as an indicator of internal consistency
(see Table 1 for national scores).
Interitem response variance. The interitem response variance
for each five dimensions was found after the reversal of negatively
keyed items. Low variance of responses on an internally consistent
scale indicates that the person responded comparably to all items.
High variance indicates that the person responded erratically and
inconsistently to different items of the scale. The mean value over
the five interitem response variances was found.
Acquiescence bias. The acquiescence index was constructed
from an equal number of positively and negatively keyed items
from each of the BFI scales that were scored in the same direction.
Negative item bias. A previous study demonstrated that dif-
ferences between aggregates of positive and negative items of the
Rosenberg Self-Esteem Scale (Rosenberg, 1965) were smaller in
developed nations (Schmitt & Allik, 2005). This indicates that
negatively worded items were interpreted differently across cul-
tures, and this, in turn, could affect the observed sex differences.
The negative item bias was defined as a difference between sums
of positively and negatively worded items of the Rosenberg Self-
Esteem Scale, which was administered parallel to the BFI in the
ISDP (Schmitt & Allik, 2005).
Across the ISDP, women reported significantly higher BFI
levels of neuroticism, agreeableness, extraversion, and consci-
entiousness than did men. Sex differences were most pro-
nounced on the Neuroticism dimension; in 49 ISDP nations,
women scored significantly higher in BFI Neuroticism than did
men. In no culture did men report significantly more neuroti-
cism, though in Indonesia and Botswana, men’s mean was
slightly higher than women’s mean. Women scored higher than
men in BFI Agreeableness in 34 ISDP nations, with only South
Korea displaying a significant difference in men reporting more
agreeableness than reported by women. Women scored higher
than men did in BFI Extraversion in 25 ISDP nations. In only
two cases—India and Malaysia— did men score significantly
higher than women on extraversion. Women scored higher than
men did in BFI Conscientiousness in 23 ISDP nations. Only in
India and Botswana did men score significantly higher than
women did on conscientiousness.
Sex differences in openness to experience were decidedly mixed
across cultures. In 37 cultures, men scored higher than women in
BFI Openness to Experience (in 8 cultures this difference was
statistically significant), but in 18 cultures, women’s self-reported
openness to experience was higher than men’s (in 4 cultures this
difference was statistically significant). These conflicting results
were not entirely unexpected as women have been found to be
more open than men to feelings, whereas men tend to be more
open to new ideas (Costa et al., 2001; McCrae et al., 2005). The
BFI Openness to Experience scale did not contain the necessary
precision to distinguish among these facets of the higher order trait
of openness to experience (McCrae & Costa, 1997).
172 SCHMITT, REALO, VORACEK, AND ALLIK
Mean z Score Differences (d) Between Women and Men in 55 Nations on Big Five Inventory (BFI) Factors
Mean zscore differences
SD Cronbach’s ␣NEOAC
France 136 0.44 0.53 0.36 0.11 0.11 0.77 9.21 .73
Netherlands 241 0.36 0.67 0.05 0.05 0.41 0.30 9.18 .77
Czech Republic 97 0.34 0.31 0.40 0.04 0.55 0.11 9.53 .73
Brazil 235 0.34 0.63 0.59 ⫺0.03 ⫺0.03 0.15 9.59 .75
Belgium 522 0.32 0.46 0.17 ⫺0.18 0.23 0.43 8.32 .61
Italy 200 0.32 0.58 0.16 0.14 0.27 0.26 8.90 .70
Slovakia 184 0.32 0.28 0.29 0.37 0.49 0.21 9.56 .72
Austria 467 0.31 0.45 0.29 ⫺0.02 0.23 0.27 9.50 .81
Spain 273 0.31 0.60 0.21 ⫺0.20 0.16 0.27 9.08 .77
Latvia 193 0.30 0.59 0.05 0.07 0.25 0.31 9.24 .74
New Zealand 274 0.30 0.35 0.34 ⫺0.06 0.28 0.22 10.49 .79
Mexico 215 0.29 0.44 0.13 ⫺0.12 0.23 0.36 10.17 .76
Morocco 182 0.29 0.81 ⫺0.04 0.12 0.27 0.12 9.22 .62
Canada 1039 0.28 0.49 0.17 ⫺0.14 0.20 0.27 8.90 .80
Estonia 188 0.28 0.61 0.22 0.33 0.28 0.01 9.74 .76
Australia 489 0.27 0.35 0.20 ⫺0.02 0.33 0.21 8.77 .65
Lebanon 312 0.27 0.63 0.06 ⫺0.13 0.30 0.10 9.03 .78
Romania 263 0.27 0.63 ⫺0.02 ⫺0.22 0.10 0.37 9.87 .68
Switzerland 251 0.27 0.30 0.52 0.03 0.01 0.25 9.73 .68
Chile 214 0.27 0.39 ⫺0.02 ⫺0.12 0.30 0.40 8.65 .81
United States 2793 0.27 0.53 0.15 ⫺0.22 0.19 0.20 8.49 .81
Serbia 246 0.26 0.31 0.35 0.46 0.26 0.13 8.73 .72
Argentina 206 0.26 0.54 0.21 ⫺0.29 0.16 0.12 8.47 .71
Peru 200 0.26 0.51 0.06 ⫺0.03 0.26 0.19 9.35 .76
Israel 394 0.24 0.80 0.04 ⫺0.17 0.19 ⫺0.08 9.87 .75
Germany 181 0.23 0.48 0.12 0.11 0.09 0.23 8.43 .78
Turkey 790 0.23 0.58 0.07 ⫺0.07 0.20 0.07 8.22 .80
Bolivia 412 0.23 0.49 0.06 0.04 0.31 0.04 9.37 .77
Lithuania 94 0.22 0.55 0.18 ⫺0.10 0.13 0.01 8.58 .69
Poland 846 0.21 0.47 0.11 0.14 0.18 0.09 10.00 .73
Malta 222 0.20 0.52 ⫺0.02 ⫺0.05 0.12 0.18 9.30 .77
Croatia 331 0.20 0.22 0.31 0.02 0.00 0.25 9.84 .76
United Kingdom 483 0.20 0.55 0.03 ⫺0.12 0.29 ⫺0.09 9.17 .80
Slovenia 182 0.19 0.45 0.05 0.20 0.18 0.07 9.34 .77
Cyprus 60 0.18 0.21 0.25 0.18 0.27 ⫺0.02 8.99 .72
Hong Kong 201 0.18 0.26 ⫺0.05 0.07 0.23 0.26 8.42 .70
South Africa 162 0.17 0.41 0.19 ⫺0.08 0.00 0.06 9.53 .71
Bangladesh 145 0.16 0.11 0.13 0.16 0.19 0.22 9.59 .80
Portugal 282 0.14 0.49 ⫺0.18 ⫺0.28 0.17 0.09 8.82 .67
Philippines 252 0.14 0.28 0.12 0.02 0.08 0.08 8.46 .80
Tanzania 136 0.13 0.05 0.03 ⫺0.12 0.29 0.14 8.50 .59
Taiwan 209 0.12 0.34 0.21 0.00 ⫺0.18 0.11 7.77 .75
Jordan 275 0.09 0.43 ⫺0.03 ⫺0.38 0.01 ⫺0.04 8.80 .65
Ethiopia 240 0.07 0.17 ⫺0.01 ⫺0.12 0.12 ⫺0.01 8.92 .48
Zimbabwe 200 0.06 0.25 ⫺0.04 ⫺0.12 ⫺0.01 0.04 9.23 .66
Malaysia 229 0.05 0.26 ⫺0.38 ⫺0.41 0.20 0.12 9.32 .74
Greece 141 0.05 0.17 ⫺0.29 ⫺0.04 0.22 0.09 7.60 .68
Japan 259 0.04 0.09 0.08 ⫺0.13 0.03 ⫺0.05 9.15 .74
South Korea 122 0.01 0.40 0.02 ⫺0.02 ⫺0.20 ⫺0.17 6.62 .79
India 200 0.01 0.60 ⫺0.38 ⫺0.46 0.09 ⫺0.27 8.19 .73
Finland 490 0.01 0.32 ⫺0.19 ⫺0.24 ⫺0.05 ⫺0.06 9.50 .71
Botswana 213 0.00 ⫺0.13 0.36 ⫺0.18 0.07 ⫺0.28 7.42 .63
Fiji 163 ⫺0.04 0.27 0.12 ⫺0.15 ⫺0.28 ⫺0.28 8.57 .60
Congo 192 ⫺0.09 0.20 ⫺0.11 ⫺0.21 ⫺0.27 ⫺0.19 8.21 .48
Indonesia 111 ⫺0.16 ⫺0.12 ⫺0.36 ⫺0.31 ⫺0.11 ⫺0.04 9.13 .68
Total average 17637 0.19 0.40 0.10 ⫺0.05 0.15 0.12 8.99 .72
Note. Standard deviation (SD) indicates the mean standard deviation around the mean values of the five personality traits. Cronbach’s ␣indicates the mean
Cronbach’s alphas across all five personality dimensions. n⫽the number of participants; GSDI ⫽General Sex Difference Index, N ⫽Neuroticism; E ⫽
Extraversion; O ⫽Openness to Experience; A ⫽Agreeableness; and C ⫽Conscientiousness.
SEX DIFFERENCES, PERSONALITY, AND CULTURE
The Magnitude of Sex Differences in Personality Across
Overall, the magnitudes of sex differences (expressed in terms
of the dstatistic, in which the mean scores of one gender are
subtracted from the mean scores of the other and are then divided
by the pooled standard deviation
) were relatively small to mod-
erate in size (see Table 1). On average, across the ISDP nations,
the magnitude of sex differences in personality traits was largest
for neuroticism (d⫽.40). In 2 cultures, Morocco and Israel, sex
differences in neuroticism were large (d⬎.80). In 17 cultures,
including France, Netherlands, Estonia, Italy, Brazil, Latvia,
Spain, Peru, Lebanon, Romania, United States, Turkey, Lithuania,
Malta, Argentina, United Kingdom, and India, sex differences in
neuroticism were moderate to large in magnitude (.50 ⬍d⬍.80).
In 29 cultures, sex differences in neuroticism were small to mod-
erate in size (.20 ⬍d⬍.50). In only 7 cultures—Bangladesh,
Tanzania, Ethiopia, Greece, Japan, Botswana, and Indonesia—
were sex differences in neuroticism negligible (d⬍.20). The
overall magnitude of sex differences in personality across the
ISDP was next largest for agreeableness (d⫽.15), followed by
conscientiousness (d⫽.12) and extraversion (d⫽.10).
In order to illustrate geographic variations in the degree of
sexual differentiation among personality traits, we grouped the 55
ISDP nations into 10 major world regions (see for details Schmitt
et al., 2007; Schmitt & 121 Members of the ISDP, 2003, 2004):
North America (3 countries), South America (5),Western Europe
(8), Eastern Europe (10), Southern Europe (6), Middle East (4),
Africa (7), Oceania (3), South or Southeast Asia (5), and East Asia
(4). It is important to acknowledge that the placement of cultures
into these world regions may be viewed as arbitrary and that
different classifications certainly may exist for various purposes.
Nevertheless, aggregation of data over geographical world regions
allowed us to notice several trends that might be hidden when
countries are observed in isolation. As shown in Figure 1, Neu-
roticism showed the strongest and most reliable sex differences. A
one-way analysis of variance (ANOVA) with world region as the
independent variable and national sex differences in neuroticism as
the dependent variable revealed a significant main effect of world
region, F(9, 45) ⫽2.43, p⬍.05. Multiple post hoc analyses (e.g.,
Tukey’s honestly significant difference) revealed no significant
differences between specific world regions.
In a one-way ANOVA with world region as the independent
variable and national sex differences in extraversion as the depen-
dent variable, we found a significant main effect of world region,
F(9, 45) ⫽2.14, p⬍.05. Again, multiple post hoc analyses (e.g.,
Tukey’s honestly significant difference) revealed no significant
differences between specific world regions. One-way ANOVAs
with world region as the independent variable and national sex
differences in agreeableness, conscientiousness, or openness to
experience as dependent variables showed no main effects of
As in the study by Costa and colleagues (Costa et al., 2001), the
magnitude of sex differences on different personality dimensions
was correlated across cultures: Those cultures in which sex differ-
ences in one domain of personality were prominent tended also to
have large sex differences in other domains. Correlations between
domains varied from .05 to .51, only three of which did not reach
statistical significance. On the basis of these strong intercorrela-
tions, we formed a General Sex Difference Index (GSDI) as the
mean average of sexual differentiation on four dimensions—
Neuroticism, Extraversion, Agreeableness, and Conscientious-
ness—for which we found that women, on average, scored higher
than men did (see Table 1 for nation scores). Averaging differ-
ences across the four women-dominated dimensions gave an over-
all index of the extent to which sex differences were emphasized
in a particular culture (see Costa et al., 2001). The GSDI was
significantly correlated with the mean value of men on four per-
sonality dimensions—Neuroticism, Extraversion, Agreeableness,
and Conscientiousness, r(54)⫽.69, p⬍.001, but was not signif-
icantly correlated with the mean score of women, r(54)⫽.25, p⫽
.06. Thus, national changes in men’s scores seemed to be the
primary contributor to sexual differentiation in personality traits
In 40 nations, computation of the GSDI resulted in a score above
.10. On this composite index, only three countries—Fiji, Congo,
and Indonesia— had a negative score (see Table 1). A one-way
ANOVA with world region as the independent variable and GSDI
as the dependent variable found a significant main effect of world
region, F(9, 45) ⫽4.03, p⬍.001. Based on this overall index,
multiple post hoc analyses (e.g., Tukey’s honestly significant
difference) revealed that the African and South/Southeast Asian
world regions tended to have smaller sex differences in personality
than did most Western world regions (Europe, North and South
America). Indeed, perhaps the most striking trend across world
regions in Figure 1 was that sex differences appear to diminish as
one moves from Western to non-Western cultures.
Convergence of Personality Trait Sex Differences in the
ISDP With Other Studies
Costa et al. (2001) computed an overall index of sex differences
in personality based on four variables. Because all the Neuroticism
and Agreeableness facets of NEO-PI-R show the same direction of
sex differences, they were included. For extraversion and openness
to experience, however, women scored higher only on some of
subscales. To represent gender differences in these domains, two
new variables—feminine extraversion and feminine openness—
were created. Feminine extraversion was calculated as (E1:
warmth ⫹E2: gregariousness ⫺E3: assertiveness ⫺E5: excite-
ment seeking ⫹E6: positive emotions)/5. Similarly, feminine
openness was calculated as (O2: aesthetics ⫹O3: feelings ⫹O4:
actions ⫺O5: ideas)/4.
Figure 2 shows the cross-measure cross-cultural convergent
correlation between the self-reported GSDI of the BFI and the
self-reported NEO-PI-R sex difference index. There were 27 over-
lapping nations among which the convergent correlation was quite
strong, r(25) ⫽.73, p⬍.001. Indeed, this is a remarkably high
The dstatistic is traditionally computed such that positive values
indicate that men are higher than women on a particular scale (Cohen,
1988). However, previous studies on sex differences in personality traits
(Costa et al., 2001) have computed dsuch that positive values indicate that
women are higher than men, and we have used this convention to increase
the comparability of the current findings with previous studies. Cohen
(1988) defined sex differences in terms of das large if differences are
greater than .80, moderate if differences are between .50 and .80, and small
if differences are between .20 and .50.
174 SCHMITT, REALO, VORACEK, AND ALLIK
value compared with relatively modest correlations between the
BFI and the NEO-PI-R domain scales (Schmitt et al., 2007). The
convergent correlation between sex differences of the BFI self-
reports and that of the NEO-PI-R reports (McCrae et al., 2005) was
smaller but still statistically significant, r(37) ⫽.48, p⬍.01. Thus,
sex differences in personality traits persisted across measuring
instruments and evaluation methods, providing evidence of con-
vergent validity for the current findings.
Psychological Origins of Sex Differences in Personality
To help understand the factors responsible for sex differences,
we correlated the nation-level personality differences between
women and men (as expressed in the GSDI) with other culture-
level variables (see Table 2). As in previous studies, sexual dif-
ferentiation was correlated with Hofstede’s individualism dimen-
sion, r(43) ⫽.48, p⬍.001. Western nations with individualistic
values exhibit greater sex differences in self-reported personality
traits than do non-Western, collectivistic cultures (Costa et al,
2001). Sex differences in personality were also positively corre-
lated with Inglehart’s survival/self-expression values, r(43) ⫽.29,
p⬍.05, postmaterialist values, r(43) ⫽.35, p⬍.01, and life
satisfaction, r(44) ⫽.32, p⬍.05. Sex differences in personality
were negatively correlated with materialist values, r(43) ⫽⫺.33,
p⬍.05. Finally, the GSDI was not significantly correlated with
Hofstede’s power distance dimension, failing to support the
Guimond et al. (2007) contention that sex differences should be
larger in cultures in which women compare themselves only with
other women and men compare themselves only with other men.
Table 2 also shows that nation-level sex differences in person-
ality were correlated with several socioeconomic indicators. The
strongest overall predictor was the HDI, which is a summary
World Region of the ISDP
Sex Difference (d) in Personality
Figure 1. Magnitude of sex differences (d) in extraversion, agreeableness, conscientiousness, and neuroticism,
across the 10 major world regions of the International Sexuality Description Project (ISDP; Schmitt & 121
Members of the ISDP, 2003).
SEX DIFFERENCES, PERSONALITY, AND CULTURE
measure consisting of three basic components: long and healthy
life, knowledge and education, and decent standard of living.
Similar results were evident for HDI-related components of GDP,
life expectancy, and school enrollment. These results converge
with previous findings showing that more modern and progressive
cultures tend to have larger sex differences in personality than do
more traditional cultures (Costa et al, 2001). The larger contribu-
tion to this correlation came from men’s shifts in personality as the
mean value of their averaged scores on four dimensions—
Neuroticism, Extraversion, Agreeableness, and Conscientious-
ness—was significantly correlated with HDI, r(53) ⫽.56, p⬍
.001, whereas the same correlation for women was insignificant,
r(53) ⫽.17, p⫽.22.
Several indicators of gender quality (including the GEM, the
GDI, the earned income ratio, and the Female Professionals and
Workers index) correlated positively with the GSDI of person-
ality traits. These findings strongly refute the social role model
approach in which greater gender equality within a society
should lead to smaller sex differences. In fact, the opposite has
now been documented across multiple samples—increasing
gender equality in a society results in larger sex differences in
personality traits (Costa et al., 2001; McCrae et al., 2005).
Similarly, we found other sociocultural indicators of sex differ-
ence show increases in more modern cultures. In modern and
egalitarian countries like Switzerland, New Zealand, and the Neth-
erlands, men have much higher systolic blood pressure than do
women. In more traditional countries like Indonesia, Bangladesh,
and Ethiopia, the blood pressure of men and that of women are
practically identical. For the 45 ISDP countries where we had
blood pressure data, the absolute difference between men and
women in their blood pressure was significantly correlated with
national HDI levels, r(43) ⫽.41, p⬍.01. Thus, like the widening
gap in personality traits, men’s blood pressure and women’s blood
pressure widens as cultures become more modern.
Still, is it the case that larger sex differences in personality
are linked to greater gender equality, or are they simply linked
to increases in general human development? The last column in
Table 2 shows the partial correlations between nation-level sex
differences (GSDI) and predictor variables when the influence
of HDI was partialled out. Most of the correlations became
Cz ec h
Ita ly Austria
Pe r u
Cr oa tia
Hon g Kong
South Af rica
Por t u g al
Ind i a
0.0 0.1 0.2 0.3 0.4 0.5 0.6
Mea n Level Sex Differences (Costa et al., 2001)
BFI Genera l Sex Differences Index
Figure 2. The cross-cultural convergent correlation between the Big Five Inventory General Sex Differences
Index (this study) and the Revised NEO Personality Inventory (Costa et al., 2001) sex differences indices,
r(25) ⫽.73, p⬍.001. Data for Austria, Canada, Czech Republic, Switzerland, and Turkey were obtained from
Robert R. McCrae (personal communication, January 27, 2006). Costa et al.’s (2001) data were averaged across
Black and White South Africans. Costa et al.’s (2001) data for Yugoslavia were matched with the Serbian data
in the current study. The dotted lines indicate 95% confidence bands around the fitted regression line.
176 SCHMITT, REALO, VORACEK, AND ALLIK
insignificant, demonstrating that most sociocultural predictors
do not have independent contributions beyond that of human
development. However, there were four predictors that made
independent contributions to sexual differentiation beyond
HDI: cultures in which there are traditional values, r(42) ⫽
⫺.31, p⬍.05, and in which people think that most people
cannot be trusted, r(43) ⫽⫺.44, p⬍.01, have smaller sex
differences, whereas when the percentage of smoking women is
high compared with that of smoking men, r(44) ⫽.35, p⬍.05,
and when the respondents are more inclined to agree with a
question irrespective its content, r(54) ⫽.32, p⬍.02, cultures
have greater disparity between men’s and women’s personality
When all four predictors were combined with the HDI and
put into a multiple regression equation, they jointly explained
54.6% of variance in the cross-cultural sex differences in per-
sonality (R⫽.74), F(5, 35) ⫽8.42, p⬍.00003. Table 3 shows
the results of the multiple regression analysis with the strongest
predictors of the GSDI. The results demonstrate that the level of
human development has the strongest contribution, but a high
proportion of smoking women and a distrust of other people
also contribute to sex differences in personality traits.
Finally, we found no support for the notion that measurement
artifacts influence the degree of sexual differentiation across cul-
tures. Although Cronbach’s alpha, r(54) ⫽.41, p⬍.001, and
negative item bias, r(53) ⫽.32, p⬍.016, significantly correlated
with size of sex differences in personality traits, their contribution
vanished when level of human development was controlled. After
accounting for variability in the HDI, only the impact of the
acquiescence bias became significant, r(54)⫽.32, p⬍.024. This
impact, however, was opposite to that of the artifact explanation.
In cultures with equal human development, when people respond
affirmatively to questions with no regard to content, men and
women are more dissimilar in personality.
Product Moment and Partial Correlations Between Mean Level General Sex Differences Index and Selected Nation-Level Indicators
Cultural value dimensions
World Values Survey (Inglehart et al., 2004)
Traditional/secular-rational 45 ⴚ0.44 ⴚ0.44 0.14 ⴚ0.31
Survival/self-expression 45 0.08 ⫺0.21 0.29 ⫺0.06
Materialist values 45 ⫺0.19 0.15 ⴚ0.33 ⫺0.06
Postmaterialist values 45 0.22 ⫺0.24 0.45 0.23
Interpersonal trust 46 ⫺0.18 ⫺0.06 ⫺0.14 ⴚ0.44
Life satisfaction 46 0.06 ⫺0.25 0.32 ⫺0.12
IBM study (Hofstede, 2001)
Power distance 45 ⫺0.22 0.04 ⫺0.21 0.03
Uncertainty avoidance 45 0.17 0.00 0.17 0.06
Individualism 45 0.31 ⫺0.24 0.48 0.29
Masculinity 45 ⫺0.06 ⫺0.15 0.08 0.04
Human Development Index (rank) 53 0.17 0.56 0.50 —
GDP per capita (US dollars) 53 ⫺0.05 ⴚ0.40 0.39 ⫺0.08
Life expectancy 53 ⫺0.12 ⴚ0.53 0.48 0.06
School enrollment 53 ⴚ0.50 0.43 ⫺0.14 ⫺0.06
Gini index 47 0.20 0.30 ⫺0.16 0.09
Gender equality indicators
Sex ratio in total population 55 0.04 0.34 ⴚ0.38 ⫺0.23
Gender Empowerment Measure 41 0.10 ⫺0.30 0.39 0.06
Gender-Related Development Index 53 ⫺0.19 ⴚ0.56 0.49 ⫺0.03
Sex ratio in smoking 47 ⴚ0.40 0.11 ⴚ0.45 ⴚ0.35
Sex ratio in school enrollment 53 0.05 ⫺0.24 0.34 0.11
Earned income ratio 53 ⫺0.13 ⫺0.15 0.08 ⫺0.03
Female Professionals and Workers 43 0.05 ⫺0.27 0.41 0.27
Sex difference in life expectancy 53 ⴚ0.31 ⴚ0.61 0.45 0.19
Sex difference in blood pressure 45 ⫺0.05 ⴚ0.38 0.31 0.14
Method quality indicators
Cronbach’s ␣55 ⫺0.02 ⴚ0.36 0.41 0.16
Interitem response variance 55 0.40 ⫺0.11 0.41 0.25
Acquiescence bias 55 0.38 0.13 0.17 0.32
Negative item bias 53 ⫺0.00 0.30 ⴚ0.33 ⫺0.05
Note. Significant p⬍兩.05兩correlations are in bold. N⫽number of countries; Mean NEAC ⫽the mean value of Neuroticism, Extraversion,
Agreeableness, and Conscientiousness scores, separately for women and men; GSDI ⫽General Sex Difference Index; GSDI
⫽General Sex Difference
Index controlled for Human Development Index 2003 (HDI; http://hdr.undp.org/statistics/data/indicators.cfm); GDP ⫽gross domestic product.
SEX DIFFERENCES, PERSONALITY, AND CULTURE
This study provides strong support for the claim that with
greater human development and with greater opportunities for
gender equality, the personalities of men and women do not
become more similar (see also Costa et al., 2001; McCrae, 2002;
McCrae et al., 2005). To the contrary, in more prosperous and
egalitarian societies the personality profiles of men and women
become decidedly less similar. Moreover, these changes appear to
result from men’s cross-cultural personality variation. In more
traditional and less developed cultures a man is, indeed, more like
a woman, at least in terms of self-reported personality traits.
Sex Roles Do Not Explain Why Sex Differences in
Personality Traits Vary Across Cultures
These findings may seem paradoxical because in traditional and
economically deprived countries the division of labor between the
sexes appears more disparate than it does in wealthy and egalitar-
ian societies. In patriarchic and traditional countries, women oc-
cupy roles that demand communal, domestic, and subordinate
behaviors more than men do. Men, on the contrary, occupy posi-
tions that demand agentive and dominant behavior for successful
sex role performance (Eagly & Wood, 1999). So far, two large-
scale cross-cultural data sets have shown that the gap between the
personality traits of men and that of women widens as the society
in which they live becomes more modern, economically affluent,
and gender egalitarian (Costa et al., 2001; McCrae et al., 2005).
This study confirms and extends this observation to a new set of
countries, including several African and Middle East countries.
An accumulating body of evidence, including the current data,
provides reason to question social role explanations of gender and
personality development (Baron-Cohen, 2003; Campbell, Shirley,
& Candy, 2004; Geary, 1998; Lytton & Romney, 1991; Maccoby,
2000; Mealey, 2000; Spiro, 1996; Tiger & Shepher, 1975). In this
study, a collection of eight different gender equality indicators
provided a comprehensive set of measures that assess disparity
between male and female roles in society. In every case, signifi-
cant findings suggest that greater nation-level gender equality
leads to psychological dissimilarity in men’s and women’s per-
sonality traits. If differences in personality traits are controlled by
the drastically different social roles that men and women play in
the society then in cultures in which women earn considerably less
than men, in which they have limited access to education, and in
which only few of them become professionals, women’s person-
ality profiles should be very different from men’s. In reality, these
women’s personality profiles are more similar to those of men.
Whatever the source of men’s and women’s personality trait
differences across cultures, differences in social roles appear un-
likely to play a significant causal role.
Method Artifacts Do Not Explain Why Sex Differences in
Personality Traits Vary Across Cultures
There are many forms of bias in personality measurement and
some of these biases are very difficult to quantify (Cheung &
Rensvold, 2000; Grimm & Church, 1999). For example, it can be
difficult to determine whether self-reports reflect role require-
ments, intrinsic differences in personality traits, or some interac-
tive combination of both. It is, however, much easier to observe
simpler biases such as dissimilar responding to positively and
negatively worded items or overall inconsistency in responses to
personality items. Schmitt and Allik (2005) observed that in coun-
tries with lower differences between positively and negatively
worded items and higher internal consistency of responses, people
tend to live longer; be economically more prosperous; and support
individualistic values and equality in rights, wealth, and power. In
this regard, this study provided no strong evidence for the artifact
explanation. Negative item bias and Cronbach’s alphas lost their
influence on the magnitude of sex differences in personality when
level of human development was controlled for. Although acqui-
escent responding became significantly related to sex differences
in personality when the impact of the HDI was partialled out, the
direction of this correlation was opposite of the predicted artifact
Evolutionary Theories May Explain Why Sex Differences
in Personality Traits Vary Across Cultures
Evolutionary theories rooted in parental investment theory
(Trivers, 1972) have predicted that sexual selection pressures have
caused men to be more prone than women to take risks and seek
social dominance, whereas women are thought to have been se-
lected to be more nurturing and cautious (Buss, 1997; MacDonald,
1995). Thus, evolutionary theories can readily account for the
existence of culturally pervasive differences between men and
women. In principle, evolutionary theories can also explain the
widening gap between the personalities of men and women by a
version of the mismatch theory (specifically, the curvilinear hy-
pothesis), according to which discrepancies between contemporary
environmental conditions and those in which early humans
evolved have begun to lessen as humans move from agricultural to
modern societies (Schmitt, 2005a). In the ancestral past, as hunter-
gatherers, men and women naturally developed sexually selected
differences in personality traits such that men were more risk
Prediction of the Mean Level General Sex Differences Index From the Best Set of Nation-Level Indicators
␤SE of ␤t(35) pn
Intercept 1.22 .23
Human Development Index (rank) .67 .17 ⫺3.91 .00 53
Interpersonal trust ⫺.43 .13 ⫺3.27 .00 46
Sex ratio in smoking ⫺.34 .12 ⫺2.76 .01 47
Traditional/secular-rational ⫺.12 .19 ⫺0.64 .53 45
Acquiescence bias .10 .14 0.68 .50 55
178 SCHMITT, REALO, VORACEK, AND ALLIK
taking and dominance seeking and women were more nurturing
and cautious. As societies rooted in agriculture and monotheism
emerged, the personalities of men and women were relatively
constrained and sex differences in personality may have been less
likely to surface (see Pasternak et al., 1997). Finally, as modern
societies have become more egalitarian (more similar to hunter-
gatherer cultures; Marlowe, 2003; Yanca & Low, 2004), innate sex
differences in personality traits may have become more likely to
materialize. However, until there are larger studies that include a
wider range of cultures—ideally including hunter-gatherer, horti-
cultural, pastoral, agricultural, and developing nations—this cur-
vilinear hypothesis must remain speculative.
Magnitude of Sex Differences in Personality Traits May
Demonstrate Gene–Environment Interaction
Like other forms of sexual dimorphism, differences in person-
ality traits may be controlled or mediated by sex-linked genes.
However, the existence of innate sex differences alone would not
explain the widening gap between the personalities of men and
women with the development of more prosperous and egalitarian
societies. In addition to the curvilinear hypothesis, there may be
other mechanisms that drive cultural variation in the magnitude of
sex differences in personality traits. According to the diathesis-
stress interaction scheme (Meehl, 1962; Monroe & Simons, 1991),
environmental pressures and life events can activate or suppress
innate predispositions to think, feel, and behave in a consistent
way. It may be the case that the genetic personality predispositions
of men and women are sensitive to certain contextual factors (e.g.,
environmental stress) in ways that differentially activate or sup-
press these predispositions (e.g., Belsky, 1999; Ellis & Garber,
Sex differences in reactivity to environmental stress have been
documented in other human attributes. For example, sex differ-
ences in height and blood pressure show increasing sexual dimor-
phism in prosperous and egalitarian societies and are relatively
attenuated in poor societies. It is universally true that on average,
men are taller than women in every human population. This sexual
dimorphism in body size reached modern levels at least 150,000
years ago or even earlier (Ruff, 2002; Wolfe & Gray, 1982) and
appears to have been produced by selection pressures that favor
relatively taller men and shorter women (Nettle, 2002; Pawlowski,
Dunbar, & Lipowicz, 2000). Over evolutionary time, such a situ-
ation tends to maintain mean-level sexual dimorphism, even
though there is considerable overlap in men’s and women’s height
distributions (Gaulin & Boster, 1985; Nettle, 2002).
Like personality traits, the degree of sexual dimorphism in
height varies across cultures. Such variations likely reflect subtle
reactions to environmental forces, such as climate, nutrition, stress,
and disease (e.g., Bogin & Rios, 2003; Frayer & Wolpoff, 1985;
Katzmarzyk & Leonard, 1998). For example, it is well documented
that well-nourished populations are more sexually dimorphic in
height than are malnourished ones, in part because male growth is
more susceptible to nutritional deficiencies during development
than is female growth (Brauer, 1982; Hamilton, 1982). A drastic
example of a more deleterious effect of environmental influence
on boys than on girls is the consequences of the atomic bombing
of Japan (Greulich, Giswan, & Turner, 1953). Sexual dimorphism
in height is higher in richer countries than in poorer countries
(Eveleth, 1975; Eveleth & Tanner, 1990; Gue´gan, Teriokhin, &
Thomas, 2000), and within cultures, sexual dimorphisms in height
are larger in richer socioeconomic classes than in lower classes
(Malina, Little, Buschang, Demoss, & Selby, 1985). The same
appears to be relevant concerning personality. In the ISDP, it
appears that men’s personality trait scores, more than women’s,
change with the development of human society. As human devel-
opment increases, men’s personalities are fully fed and sex differ-
ences tend to increase.
Like personality traits, systolic blood pressure is stable in time
and has a considerable heritable component (Hottenga et al.,
2005). Both systolic and diastolic blood pressures demonstrate
significant heritability ranging from 34% to 67%. Correlations
over time across an average period of 7.1 years are between .41
and .70. At the same time, there is no evidence for heritability of
sex differences in blood pressure (Hottenga et al., 2005). As
expected, blood pressure is higher in modern and economically
developed societies than in traditional and economically less de-
veloped countries (Pollard, Brush, & Harrison, 1991; Waldron et
al., 1982). Nevertheless, the correlation between mean level of sex
difference in blood pressure and level of human development is
positive. In countries like Switzerland, New Zealand, and the
Netherlands, men have much higher systolic blood pressure than
do women. In more traditional countries like Indonesia, Bang-
ladesh, and Ethiopia, the blood pressure of men and women is
practically identical. Again, like personality traits, the gap between
men’s and women’s blood pressure widens with increasing human
Thus, larger sex differences in personality among modern na-
tions may reflect a more general biological trend toward greater
dimorphism in resource rich environments and reduced dimor-
phism in constrained or high stress environmental conditions
(Teder & Tammaru, 2005). It seems to be also universal that the
larger of the two sexes (among insects females are typically larger
than males) is the more vulnerable to environmental pressures
(Abouheif & Fairbairn, 1997; Teder & Tammaru, 2005). It is
therefore possible that the observed level of sexual dimorphism in
more developed countries corresponds to a natural tendency for
men and women to develop differing personalities: It is mainly
men, not women, who became less neurotic but also less agreeable
and conscientious in their self-descriptions. In less fortunate con-
ditions, the innate personality differences between men and
women are attenuated. Although speculative, another illustration
of this principle may be seen regarding sex differences in compet-
itiveness: Even when opportunities and incentives for achieving in
sport grow in a way to become more equitable, sex differences in
the proportion of men to women who run relatively fast increase
with greater opportunity (Deaner, 2006).
Like morphological and physiological features, sex differences
in personality are vulnerable to restraining environmental pres-
sures. As a society becomes more prosperous and more egalitarian,
innate dispositional differences between men and women have
more space to develop and the gap that exists between men and
women in their personality traits becomes wider. As summarized
by Ridley (2003),
Ironically, the more egalitarian a society is, the more innate factors
will matter. In a world where everybody gets the same food, the
heritability of height and weight will be high; in a world where some
SEX DIFFERENCES, PERSONALITY, AND CULTURE
live in luxury and others starve, the heritability of weight will be low.
Likewise, in a world where everybody gets the same education, the
best jobs will go to those with the most native talent. That’s what the
word meritocracy means. (Ridley, 2003, p. 262)
This is perhaps the same reason why preexisting gaps between
advantaged and less advantaged persons across different domains,
including health and education, often widen when opportunities
are made more equitable (Ceci & Papierno, 2005; Gottfredson,
This interactive gene-environment view of personality develop-
ment is amenable to empirical verification because it supposes that
heritability of personality traits is higher in developed societies and
lower in more traditional and less modern cultures. Previous stud-
ies have revealed a broad genetic influence on all Big Five per-
sonality traits, explaining from 40% to 60% of their total variance
(Jang, Livesley, & Vernon, 1996; Riemann, Angleitner, & Strelau,
1997). Cross-cultural studies have shown that genetic influences
remain invariant across diverse nations (Yamagata et al., 2006).
Unfortunately, all existing twin studies of personality have been
carried out in highly developed countries. Therefore, the prediction
that the heritability of personality traits would be lower in less
developed cultures remains to be demonstrated by future investi-
In summary, we have found that differences between men and
women in their personality traits become more extreme with the
increasing development of human society. Reported ISDP data
indicate that human development—long and healthy life, access to
education, and economic wealth—is a primary correlate of the gap
between men and women in their personality traits. Most other
correlates appear to be mediated by general level of development
in health, education, and economy. In societies in which longevity
is threatened by poor health, in which only a fraction of people
have opportunities for a good education, and in which people
suffer from economic hardship, the development of one’s inherent
personality traits is more restrained. In these hold-down or mal-
nourished conditions, there is a smaller variation around the mean
level of personality traits across the ISDP, and it is more likely that
any one individual is more like all other individuals. In traditional
and less developed countries, therefore, an average man is more
like an average woman, not in terms of his social roles or value
preferences, but in his basic personality tendencies to feel, think,
and act in a way more comparable with women.
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Received August 28, 2006
Revision received July 3, 2007
Accepted July 18, 2007 䡲
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