Research typically reveals that outgroups are regarded with disinterest at best and hatred and enmity at worst. Working from an evolutionary framework, we identify a unique pattern of outgroup attraction. The small-group lifestyle of pre-human ancestors plausibly limited access to genetically diverse mates. Ancestral females may have solved the inbreeding dilemma while balancing parental investment pressures by mating with outgroup males either via converting to an outgroup or cuckolding the ingroup. A vestige of those mating strategies might manifest in human women as a cyclic pattern of attraction across the menstrual cycle, such that attraction to outgroup men increases as fertility increases across the cycle. Two studies, one using a longitudinal method and the other an experimental method, evidenced the hypothesized linear relationship between attraction to outgroup men and fertility in naturally cycling women.

References

Aiello, L. C., Dunbar, R. I. M. ( 1993 ). Neocortex size, group size, and the evolution of language . Current Anthropology, 34, 184 - 193 .

Google Scholar Crossref | ISI

Alvergne, A., Lummaa, V. ( 2010 ). Does the contraceptive pill alter mate choice in humans? Trends in Ecology & Evolution, 25, 171 - 179 .

Google Scholar Crossref | Medline | ISI

Baumeister, R. F., Leary, M. R. ( 1995 ). The need to belong: Desire for interpersonal attachment as a fundamental human motivation . Psychological Bulletin, 117, 497 - 529 .

Google Scholar Crossref | Medline | ISI

Bobo, L., Zubrinsky, C. L. ( 1996 ). Attitudes on residential integration: Perceived status differences, mere in-group preference, or racial prejudice? Social Forces, 74, 883 - 909 .

Google Scholar Crossref | ISI

Boldry, J. G., Gaertner, L., Quinn, J. ( 2007 ). Measuring the measures: A meta-analytic investigation of the measures of outgroup homogeneity . Group Processes & Intergroup Relations, 10, 157 - 178 .

Google Scholar SAGE Journals | ISI

Brewer, M. B. ( 1999 ). The psychology of prejudice: Ingroup love or outgroup hate? Journal of Social Issues, 55, 429 - 444 .

Google Scholar Crossref | ISI

Brewer, M. B. ( 2007 ). The social psychology of intergroup relations: Social categorization, ingroup bias, and outgroup prejudice . In Kruglanski, A. W., Higgins, E. T. (Eds.), Social psychology: Handbook of basic principles ( 2nd ed. , pp. 695 - 715 ). New York, NY : Guilford Press .

Google Scholar

Brewer, M. B., Caporael, L. R. ( 2006 ). An evolutionary perspective on social identity: Revisiting Groups . In Schaller, M., Simpson, J. A., Kenrick, D. T. (Eds.), Evolution and social psychology (pp. 141 - 161 ). New York, NY : Psychology Press .

Google Scholar

Brook, B. W., Bradshaw, C. J. A., Traill, L. W., Frankham, R. ( 2011 ). Minimum viable population size: Not magic, but necessary . Trends in Ecology & Evolution, 26, 619 - 620 .

Google Scholar Crossref | Medline | ISI

Buss, D. M. ( 1989 ). Sex differences in human mate preferences: Evolutionary hypotheses tested in 37 cultures . Behavioral and Brain Sciences, 12, 1 - 49 .

Google Scholar Crossref | ISI

Caporael, L. R. ( 1997 ). The evolution of truly social cognition: The core configurations model . Personality and Social Psychology Review, 1, 276 - 298 .

Google Scholar SAGE Journals

Caporael, L. R. ( 2001 ). Parts and wholes: The evolutionary importance of groups . In Sedikides, C., Brewer, M. B. (Eds.), Individual self, relational self, collective self (pp. 241 - 258 ). Philadelphia, PA : Psychology Press .

Google Scholar

Caporael, L. R. ( 2007 ). Evolutionary theory for social and cultural psychology . In Kruglanski, A. W., Higgins, E. T. (Eds.), Social psychology: Handbook of basic principles ( 2nd ed. , pp. 3 - 18 ). New York, NY : Guilford Press .

Google Scholar

Caporael, L. R., Brewer, M. B. ( 1991 ). Reviving evolutionary psychology: Biology meets society . Journal of Social Issues, 47, 187 - 195 .

Google Scholar Crossref | ISI

Chapais, B. ( 2008 ). Primeval kinship. Cambridge, MA : Harvard University Press .

Google Scholar

Chapais, B. ( 2013 ). Monogamy, strongly bonded groups, and the evolution of human social structure . Evolutionary Anthropology, 22, 52 - 65 .

Google Scholar Crossref | Medline | ISI

Charlesworth, D., Willis, J. H. ( 2009 ). The genetics of inbreeding depression . Nature Reviews Genetics, 10, 783 - 796 .

Google Scholar Crossref | Medline | ISI

Clutton-Brock, T. H. ( 1989 ). Female transfer and inbreeding avoidance in social mammals . Nature, 337, 70 - 72 .

Google Scholar Crossref | Medline | ISI

De Houwer, J . ( 2001 ). A structural and process analysis of the Implicit Association Test . Journal of Experimental Social Psychology, 37, 443 - 451 .

Google Scholar Crossref | ISI

Drigotas, S. M., Safstrom, C. A., Gentilia, T. ( 1999 ). An investment model prediction of dating infidelity . Journal of Personality and Social Psychology, 77, 509 - 524 .

Google Scholar Crossref | ISI

Dunbar, R. I. M. ( 1993 ). Coevolution of neocortical size, group size, and language in humans . Behavioral and Brain Sciences, 16, 681 - 735 .

Google Scholar Crossref | ISI

Durante, K. M., Griskevicius, V., Simpson, J. A., Li, N. P. ( 2012 ). Ovulation leads women to perceive sexy cads as good dads . Journal of Personality and Social Psychology, 103, 292 - 305 .

Google Scholar Crossref | Medline | ISI

Fessler, D. M. T., Navarrete, C. D. ( 2003 ). Domain-specific variation in disgust sensitivity across the menstrual cycle . Evolution & Human Behavior, 24, 406 - 417 .

Google Scholar Crossref | ISI

Fiske, S. T. ( 2000 ). Stereotyping, prejudice, and discrimination at the seam between the centuries: Evolution, culture, mind, and brain . European Journal of Social Psychology, 30, 299 - 322 .

Google Scholar Crossref | ISI

Foley, R. ( 1996 ). The adaptive legacy of human evolution: A search for the environment of evolutionary adaptedness . Evolutionary Anthropology, 4, 194 - 203 .

Google Scholar Crossref

Gaertner, L., Iuzzini, J., Guerrero, W. M., Oriña, M. M. ( 2006 ). Us without them: Evidence for an intragroup origin of positive ingroup regard . Journal of Personality and Social Psychology, 90, 426 - 439 .

Google Scholar Crossref | Medline | ISI

Gaertner, S. L., Dovidio, J. F. ( 2010 ). Intergroup bias . In Fiske, S. T., Gilbert, D. T., Lindzey, G. (Eds.), Handbook of social psychology ( 5th ed. , pp. 1084 - 1121 ). Hoboken, NJ : John Wiley & Sons .

Google Scholar

Gangestad, S. W., Simpson, J. A. ( 2000 ). The evolution of human mating: Trade-offs and strategic pluralism . Behavioral and Brain Sciences, 23, 573 - 644 .

Google Scholar Crossref | Medline | ISI

Gangestad, S. W., Simpson, J. A., Cousins, A. J., Garver-Apgar, C. E., Christensen, P. N. ( 2004 ). Women’s preferences for male behavioral displays change across the menstrual cycle . Psychological Science, 15, 203 - 207 .

Google Scholar SAGE Journals | ISI

Gangestad, S. W., Thornhill, R. ( 1998 ). Menstrual cycle variation in women’s preferences for the scent of symmetrical men . Proceedings of the Royal Society of London: Biological Sciences, 265, 927 - 933 .

Google Scholar Crossref | Medline | ISI

Garnett, S. T., Zander, K. K. ( 2011 ). Minimum viable population limitations ignore evolutionary history . Trends in Ecology & Evolution, 26, 618 - 619 .

Google Scholar Crossref | Medline | ISI

Garver-Apgar, C. E., Gangestad, S. W., Thornhill, G. R. ( 2008 ). Hormonal correlates of women’s mid-cycle preference for the scent of symmetry . Evolution & Human Behavior, 29, 223 - 232 .

Google Scholar Crossref | ISI

Garver-Apgar, C. E., Gangestad, S. W., Thornhill, R., Miller, R. D., Olp, J. J. ( 2006 ). Major histocompatibility complex alleles, sexual responsivity, and unfaithfulness in romantic couples . Psychological Science, 17, 830 - 835 .

Google Scholar SAGE Journals | ISI

Gildersleeve, K. A., Haselton, M. G., Fales, M. ( 2014 ). Do women’s mate preferences change across the ovulatory cycle? A meta-analytic review . Psychological Bulletin, 140, 1205 - 1259 .

Google Scholar Crossref | Medline | ISI

Gramzow, R. H., Gaertner, L. ( 2005 ). Self-esteem and favoritism toward novel in-groups: The self as an evaluative base . Journal of Personality and Social Psychology, 88, 801 - 815 .

Google Scholar Crossref | Medline | ISI

Greenwald, A. G., Nosek, B. A., Banaji, M. R. ( 2003 ). Understanding and using the Implicit Association Test: I. An improved scoring algorithm . Journal of Personality and Social Psychology, 85, 197 - 216 .

Google Scholar Crossref | Medline | ISI

Hewstone, M., Hantzi, A., Johnston, L. ( 1991 ). Social categorization and person memory: The pervasiveness of race as an organizing principle . European Journal of Social Psychology, 21, 517 - 528 .

Google Scholar Crossref | ISI

Hill, K. R., Walker, R. S., Bozicevic, M., Eder, J., Headland, T., Hewlett, B., . . . Wood, B. ( 2011 ). Co-residence patterns in hunter-gatherer societies show unique human social structure . Science, 331, 1286 - 1289 .

Google Scholar Crossref | Medline | ISI

Insko, C. A., Schopler, J. ( 1998 ). Differential distrust of groups and individuals . In Sedikides, C., Schopler, J., Insko, C. A. (Eds.), Intergroup cognition and intergroup behavior (pp. 75 - 107 ). Mahwah, NJ : Lawrence Erlbaum .

Google Scholar

Lieberman, D., Pillsworth, E. G., Haselton, M. G. ( 2011 ). Kin affiliation across the ovulatory cycle: Females avoid fathers when fertile . Psychological Science, 22, 13 - 18 .

Google Scholar SAGE Journals | ISI

Marlow, F. W. ( 2005 ). Hunter-gatherers and human evolution . Evolutionary Anthropology, 14, 54 - 67 .

Google Scholar Crossref | ISI

McDonald, M. M., Asher, B. D., Kerr, N. L., Navarrete, C. D. ( 2011 ). Fertility and intergroup bias in racial and minimal-group contexts: Evidence for shared architecture . Psychological Science, 22, 860 - 865 .

Google Scholar SAGE Journals | ISI

Meltzer, A. L. ( 2016 ). Wives with masculine husbands report increased marital satisfaction near peak fertility . Evolutionary Behavioral Sciences. Advance online publication. doi:10.1037/ebs0000083

Google Scholar Crossref

Mullen, B., Hu, L. ( 1989 ). Perceptions of ingroup and outgroup variability: A meta-analytic integration . Basic and Applied Social Psychology, 10, 233 - 252 .

Google Scholar Crossref | ISI

Navarrete, C. D., Fessler, D. M. T., Fleischman, D. S., Geyer, J. ( 2009 ). Race bias tracks conception risk across the menstrual cycle . Psychological Science, 20, 661 - 665 .

Google Scholar SAGE Journals | ISI

Neuberg, S. L., Kenrick, D. T., Schaller, M. ( 2010 ). Evolutionary social psychology . In Fiske, S. T., Gilbert, D. T., Lindzey, G. (Eds.), Handbook of social psychology ( 5th ed. , pp. 761 - 796 ). Hoboken, NJ : John Wiley & Sons .

Google Scholar Crossref

Olson, M. A., Fazio, R. H. ( 2003 ). Relations between implicit measures of prejudice. What are we measuring? Psychological Science, 14, 636 - 639 .

Google Scholar SAGE Journals | ISI

Olsson, A., Ebert, J. P., Banaji, M. R., Phelps, E. A. ( 2005 ). The role of social groups in the persistence of learned fear . Science, 309, 785 - 787 .

Google Scholar Crossref | Medline | ISI

Ostrom, T. M., Sedikides, C. ( 1992 ). Out-group homogeneity effects in natural and minimal groups . Psychological Bulletin, 112, 536 - 552 .

Google Scholar Crossref | ISI

Penn, A. J., Potts, W. K. ( 1999 ). The evolution of mating preferences and major histocompatibility complex genes . The American Naturalist, 153, 145 - 164 .

Google Scholar Crossref | ISI

Penton-Voak, I. S., Perrett, D. I. ( 2000 ). Female preference for male faces changes cyclically—Further evidence . Evolution & Human Behavior, 21, 39 - 48 .

Google Scholar Crossref | ISI

Pettigrew, T. F., Tropp, L. R. ( 2006 ). A meta-analytic test of Intergroup Contact Theory . Journal of Personality and Social Psychology, 90, 751 - 783 .

Google Scholar Crossref | Medline | ISI

Puts, D. ( 2005 ). Mating context and menstrual phase affect women’s preferences for male voice pitch . Evolution & Human Behavior, 26, 388 - 397 .

Google Scholar Crossref | ISI

Raudenbush, S. W., Bryk, A. S. ( 2002 ). Hierarchical linear models: Applications and data Analysis models. Thousand Oaks, CA : SAGE .

Google Scholar

Roberts, S. C., Little, A. C. ( 2008 ). Good genes, complementary genes, and human mate preferences . Genetica, 132, 309 - 321 .

Google Scholar Crossref | Medline | ISI

Schaller, M., Neuberg, S. L. ( 2012 ). Danger, disease, and the nature of prejudice(s) . Advances in Experimental Social Psychology, 46, 1 - 54 .

Google Scholar Crossref | ISI

Schaller, M., Simpson, J. A., Kenrick, D. T. (Eds.). ( 2006 ). Evolution and social psychology. New York, NY : Psychology Press .

Google Scholar

Schopler, J., Insko, C. A., Wieselquist, J., Pemberton, M., Witcher, B., Kozar, R., …Wildschut, T. ( 2001 ). When groups are more competitive than individuals: The domain of the discontinuity effect . Journal of Personality and Social Psychology, 80, 632 - 644 .

Google Scholar Crossref | Medline | ISI

Sears, D. O. ( 1983 ). The person-positivity bias . Journal of Personality and Social Psychology, 44, 233 - 250 .

Google Scholar Crossref | ISI

Sedikides, C., Skorownski, J. J. ( 1997 ). The symbolic self in evolutionary context . Personality and Social Psychology Review, 1, 80 - 102 .

Google Scholar SAGE Journals

Senn, C. Y., Dzinas, K. ( 1996 ). Measuring fear of rape: A new scale . Canadian Journal of Behavioral Science, 28, 141 - 144 .

Google Scholar Crossref | ISI

Stevens, L. A., Fiske, S. T. ( 1995 ). Motivation and cognition in social life: A social survival perspective . Social Cognition, 13, 189 - 214 .

Google Scholar Crossref | ISI

Stringer, C., McKie, R. ( 1997 ). African exodus: The origins of modern humanity. London, England : Cape .

Google Scholar

Tattersall, I. ( 2012 ). Masters of the planet: In search for our human origins. New York, NY : Palgrave Macmillan .

Google Scholar

Thorndike, E. L. ( 1920 ). A constant error in psychological ratings . Journal of Applied Psychology, 4, 25 - 29 .

Google Scholar Crossref

Thornhill, R., Gangestad, S. W. ( 2008 ). The evolutionary biology of human female sexuality. Oxford, UK : Oxford University Press .

Google Scholar

Thornhill, R., Thornhill, N. W. ( 1992 ). The evolutionary psychology of men’s coercive sexuality . Behavioral and Brain Sciences, 15, 363 - 421 .

Google Scholar Crossref | ISI

Traill, L. W., Bradshaw, C. J. A., Brook, B. W. ( 2007 ). Minimum viable population size: A meta-analysis of 30 years of published estimates . Biological Conservation, 139, 159 - 166 .

Google Scholar Crossref | ISI

Trivers, R. L. ( 1972 ). Parental investment and sexual selection . In Campbell, B. (Ed.), Sexual selection and the descent of man, 1871-1971 (pp. 136 - 179 ). Chicago, IL : Aldine .

Google Scholar

Van Vugt, M . ( 2009 ). Sex differences in intergroup competition, aggression, and warfare: The male warrior hypothesis . Annals of the New York Academy of Sciences, 1167, 124 - 134 .

Google Scholar Crossref | Medline | ISI

Van Vugt, M., De Cremer, D., Janssen, D. P. ( 2007 ). Gender differences in cooperation and competition: The male-warrior Hypothesis . Psychological Science, 18, 19 - 23 .

Google Scholar SAGE Journals | ISI

Wang, L., Maxwell, S. E. ( 2015 ). On disaggregating between-person and within-person effects with longitudinal data using multilevel models . Psychological Methods, 20, 63 - 83 .

Google Scholar Crossref | Medline | ISI

Wilcox, A. J., Dunson, D. B., Weinberg, C. R., Trussell, J., Baird, D. D. ( 2001 ). Likelihood of conception with a single act of intercourse: Providing benchmark rates for assessment of post-coital contraceptives . Contraception, 63, 211 - 215 .

Google Scholar Crossref | Medline | ISI

Wilson, D. S., Sober, E. ( 1994 ). Reintroducing group selection to the human behavioral sciences . Behavioral and Brain Sciences, 17, 585 - 654 .

Google Scholar Crossref | ISI

Wobst, H. M. ( 1974 ). Boundary conditions for Paleolithic social systems: A simulation approach . Society for American Archaeology, 39, 147 - 178 .

Google Scholar

Wood, W., Kressel, L., Joshi, P., Louie, B. ( 2014 ). Meta-analysis of menstrual cycle effects on women’s mate preferences . Emotion Review, 6, 229 - 249 .

Google Scholar SAGE Journals | ISI