PPSXXX10.1177/1745691613484767Eagly, WoodThe Nature–Nurture Debates: 25 Years of Challenges 484767research-article2013 Perspectives on Psychological Science XX(X) 1 –18 The Nature–Nurture Debates: 25 Years © The Author(s) 2013 Reprints and permissions: sagepub.com/journalsPermissions.nav of Challenges in Understanding the DOI: 10.1177/1745691613484767 Psychology of Gender pps.sagepub.com Alice H. Eagly1 and Wendy Wood2 1Northwestern University and 2University of Southern California Abstract Nature–nurture debates continue to be highly contentious in the psychology of gender despite the common recognition that both types of causal explanations are important. In this article, we provide a historical analysis of the vicissitudes of nature and nurture explanations of sex differences and similarities during the quarter century since the founding of the Association for Psychological Science. We consider how the increasing use of meta-analysis helped to clarify sex difference findings if not the causal explanations for these effects. To illustrate these developments, this article describes socialization and preferences for mates as two important areas of gender research. We also highlight developing research trends that address the interactive processes by which nature and nurture work together in producing sex differences and similarities. Such theorizing holds the promise of better science as well as a more coherent account of the psychology of women and men that should prove to be more influential with the broader public. Keywords psychology of gender, sex differences and similarities, nature and nurture, meta-analysis Is nature or nurture the stronger influence on sex differ- pairing its title and author (conducted March 29, 2013). ences and similarities? If asked, most psychologists would Written in part from the perspective of the author’s own probably reply that the question is misguided. Obviously, career decisions, the article cites mainly the opinions both are influential. Yet, as we show in this article, expressed by other women with highly successful careers nature–nurture debates have remained highly conten- (e.g., Sheryl Sandberg, Elizabeth Warren). tious in the psychology of gender, and contemporary Although Slaughter’s presentation is highly engaging, researchers only sometimes integrate the two causal many of the topics that she covered could have been influences. More commonly, researchers focus on one linked to extensive psychological research (e.g., maternal type of cause to the exclusion of the other or treat them employment, stereotype threat, work–life balance). When as competing explanations. In analyzing the state of these touching on the key issue of causes of the parental divi- nature–nurture debates in psychological science, we sion of childcare responsibilities, Slaughter opted for her invoke the terms in their broadest meaning, whereby personal insight that, despite the influence of social nature refers to biological structures and processes and expectations, maternal instinct (“a maternal imperative,” nurture refers to sociocultural influences. p. 92) is critical. Even though Slaughter’s expertise is in There is no doubt that these issues are important and international relations, it is fair to ask why scientific psy- absorbing to the general public as well as scientists. chology did not enter into her analysis. Moreover, However, despite the immense amount of psychological Slaughter’s approach is not unusual: Authors who write research on gender, often it does not inform public dis- about the engaging gender questions of the day often fail course on gender issues. For example, 2012’s most widely to ground their answers in psychological research. Why? discussed journalistic treatment of gender issues is Anne- Marie Slaughter’s article “Why Women Still Can’t Have It Corresponding Author: All,” which appeared in the July–August issue of The Alice Eagly, Department of Psychology, Northwestern University, 2029 Atlantic. Evidence of the article’s success lies in the Sheridan Road, Evanston, IL 60201 approximately 370,000 hits produced by a Google search E-mail: [email protected] 2 Eagly, Wood In this article, we argue that these failures are due in part instinct (e.g., Galton, 1907; McDougall, 1923; Thorndike, to the conflicting messages that scientists convey to the 1906). In keeping with their gender-as-nurture message, public about the psychology of women and men. feminist psychologists also advocated separating sex as a In this article, we analyze changes in psychologists’ biological influence from gender as a sociocultural influ- thinking about nature and nurture by tracing the psychol- ence (e.g., Unger, 1979). In feminist research, gender ogy of gender from the founding of the Association for then received far more emphasis than sex, as illustrated Psychological Science in 1988 to the present day. We thus by Bem’s (1974, 1981) studies demonstrating that gender consider the last quarter century of research. Though we identity, as an individual difference, predicted sex-related recognize the highly varied content of research in basic behavior better than the dichotomous variable of sex. and applied domains, we focus this article on the central The 1980s marked the end of this relative supremacy issue of nature and nurture causation of sex differences of nurture explanations of the psychology of women and and similarities in traits, abilities, behavioral tendencies, men and the beginning of a powerful reassertion of and attitudes and beliefs. For researchers who address nature. Evolutionary psychologists advocated for nature these issues, one dramatic shift in the last quarter century by emphasizing evolved, inherited dispositions in women is the general acceptance by psychologists of meta-analysis and men, as illustrated by Buss’s research (1989) on the as the most appropriate method for aggregating the find- mate preferences of women and men. The theoretical ings of groups of related studies that have compared the writings of Tooby and Cosmides (1989, 1992) attracted sexes. Although this methodological advance guides gen- attention, and Daly and Wilson’s (1983) engaging book der researchers toward acknowledging the systematic pat- proposing evolutionary explanations of various human terning of sex differences and similarities, resolving behaviors reached a wide audience. Although evolution- nature–nurture causal issues remains fraught with conflict. ary theory had been applied to human behavior in the preceding decade, labeled as sociobiology (e.g., Trivers, Historical Trends in Research on Sex 1972; Wilson, 1975), it gained prominence mainly through Differences and Similarities evolutionary psychology. Another source of the rise of nature in the 1980s and The beginning of the past quarter century marked the beyond was psychologists’ increasing efforts to apply the end of an era in psychology with a strong tilt toward science of brain structure and hormones to the psychol- nurture-related explanations of sex-related differences. In ogy of women and men (Hines, 1982; Hines & Green, that period, most developmental psychologists had 1991; Notman & Nadelson, 1991). Although skeptics emphasized socialization and learning as important abounded, especially among feminists (Bleier, 1991), causes (Bandura, 1977; Kagan, 1964; Mischel, 1966), and research in this area proceeded at a rapid pace. The social and personality psychologists had emphasized ste- hypothesis that prenatal and early postnatal androgens reotypes, norms, identities, and roles that support gender affect brain structure and subsequent behavior had roots differentiation in cognition and social behavior (e.g., in earlier research (e.g., Money & Ehrhardt, 1972) and Bem, 1974; Deaux, 1984; Eagly, 1983; Spence & Helmreich, became well-accepted in the 1990s (Collaer & Hines, 1978; Williams & Best, 1982). Despite this emphasis on 1995). Popular themes included sex differences in the nurture, Maccoby and Jacklin’s (1974) influential review relative dominance of the cerebral hemispheres and in considered both biological factors and socialization as the size of the corpus callosum, which connects the cere- potentially causal and raised questions about the consis- bral hemispheres (e.g., Davatzikos & Resnick, 1998). tency and quality of the evidence on sex differences and Researchers also focused attention on the ways that hor- similarities. mones activate behaviors, especially testosterone’s rela- The feminist movement was an important influence tions to dominance and aggression (e.g., Mazur & Booth, on theories of gender because most psychologists who 1998; Sherwin, 1988). Somewhat later, oxytocin became a were allied with the wave of feminism that began in the focus of research concentrating on its relation to sex dif- 1960s were firmly in the nurture camp (Eagly, Eaton, ferences in stress-induced responses and bonding (Taylor Rose, Riger, & McHugh, 2012). Feminist psychologists et al., 2000). argued that many scientists had wrongly ascribed the This rise of nature explanations of sex-related differ- behaviors of women to their intrinsic nature and failed to ences in the 1980s and beyond did not staunch the flow recognize the causes embedded in the social context of of research favoring nurture explanations. Instead, psy- women’s lives (e.g., Weisstein, 1968). In vividly making chologists exploring the effects of social experience on this point, Shields (1975) challenged the gender-as-nature men and women developed many new research ques-