Research Article Males’ Greater Tolerance of Same-Sex Peers Joyce F. Benenson, 1,2 Henry Markovits, 3 Caitlin Fitzgerald, 1 Diana Geoffroy, 1 Julianne Flemming, 1 Sonya M. Kahlenberg, 2 and Richard W. Wrangham 2 1 Department of Psychology, Emmanuel College; 2 Department of Biological Anthropology, Harvard University; and 3 Department of Psychology, Universite ´ du Que ´bec a ` Montre ´al ABSTRACT—Three studies were conducted to examine the often-cited conclusion that human females are more so- ciable than males. Using perceptions of roommates, roommate changes at three collegiate institutions, and an experimental manipulation of friendship beliefs, the studies demonstrated unequivocally that males exhibit a higher threshold of tolerance for genetically unrelated same-sex individuals than females do. Tolerance was de- fined as acceptance of the stresses and strains within relationships. Results are discussed in terms of potential underlying mechanisms and ultimate explanations. More than 40 years ago, Bakan (1966) transformed under- standing of sex differences in social behavior by concluding that human females are more communal or sociable than males, who are more agentic or task oriented. Subsequent, often-cited characterizations of females versus males provide nuanced modifications of this fundamental theme. Prominent character- izations indicate that females, relative to males, are interper- sonal, rather than individualistic (Block, 1973); are connected, rather than separate (Chodorow, 1978; Gilligan, 1982); are in- terdependent, rather than autonomous (Johnston, 1988); are invested in connection, rather than status (Tannen, 1990); focus on maintaining intimacy, rather than distance (Winstead & Griffin, 2001); and, under stressful conditions, are more prone to ‘‘tend-and-befriend,’’ rather than to ‘‘fight-or-flight’’ (Taylor et al., 2000). This large literature rests on consistent findings, across diverse cultures, that from early childhood throughout adulthood, females engage in more verbal exchange of intimate information than males do (Buhrmester & Prager, 1995; Verkuyten & Masson, 1996; Winstead & Griffin, 2001). This characterization of sex differences in social interaction has been ubiquitously accepted across the social sciences, despite a number of inconsistent findings. Three pieces of evi- dence in particular challenge this position. First, numerous studies of genetically unrelated same-sex peers from childhood through adulthood have documented that, across diverse cul- tures, males form larger, more inclusive, and more intercon- nected networks than females (Markovits, Benenson, & Dolenszky, 2001; Savin-Williams, 1980; Vigil, 2007). Second, across ages and cultures, additional studies have demonstrated that same-sex friendships of males endure longer than those of females (Benenson & Alavi, 2004; Benenson & Christakos, 2003; Kon & Losenkov, 1978; Vigil, 2007). Third, studies out- side psychology, including ethnographic, political, military, and business studies, have provided strong cross-cultural evidence of greater cooperation among unrelated males than among un- related females (Alexander, 1987; Tiger, 1969; Wrangham, 1999). A more complete perspective of human nature requires that these literatures be included. Contrary to the widespread conclusion that females are the more sociable sex, these additional bodies of evidence suggest that human males’ threshold for tolerance of same-sex peers is higher than that of females. Tolerance is defined simply as acceptance of the inevitable stresses and strains of relation- ships. Because degree of tolerance among genetically unrelated individuals strongly influences access to critical physical and social resources and degree of cooperation across animal spe- cies, detailed analysis of sex differences in tolerance provides an important window into each sex’s social behavior (Kappeler, 2000; Sterck, Watts, & van Schaik, 1997) and, more generally, into the relative tolerance of species (Hare, Melis, Woods, Hastings, & Wrangham, 2007). Chimpanzees, Pan troglodytes, illustrate the complexity of sex differences in sociability. Male chimpanzees exhibit con- sistently higher levels of physical aggression than females in their greater levels of competition for status and mates (Muller, Address correspondence to Joyce F. Benenson, Department of Psychology, Emmanuel College, 400 The Fenway, Boston, MA 02115, e-mail: benensjo@emmanuel.edu. PSYCHOLOGICAL SCIENCE 184 Volume 20—Number 2 Copyright r 2009 Association for Psychological Science