Using Evolutionary Psychology to Account for Sex Differences and Similarities in Psychological Tendencies

Shared evolutionary selection pressures have created many similar cognitive processes and interaction strategies in both sexes. However, evolutionary psychologists focus less on sex similarities than sex differences. In a study on mate preferences, participants rated the importance of nine items for either a long-term or a short-term relationship. Sex differences consistent with evolutionary theory were found for family background and body shape. Other findings supported the notion of sex similarities—participants rated ambition, meeting parents, and faithfulness as significantly more important in the long-term situation than in the short-term situation. Discussion focuses on the need of evolutionary psychological theories to account for both similarities and differences between the sexes. A great deal of attention has recently been given to an evolutionary psychological perspective on human mating. A main focus of this approach has been to identify sex differences in the “mating game. ” Several models are relevant. Trivers’s (1972) model of parental investment used evolutionary theory to predict sex differences in mating strategies. The theory proposed that parental investment in reproduction differed widely between males and females. The consequences of a sexual encounter for a male could be reduced to a pleasurable experience; whereas, a female faced years of parenting and lost mating opportunities. Given these circumstances, it was hypothesized that females would be more selective in all sexual encounters, using short-term strategies to evaluate a mate for long-term potential. Males, on the other hand, should have evolved promiscuous behaviors in order to maximize their mating opportunities and ultimately their genetic legacy. Buss and Schmitt (1993) identified differences in the problems faced by human males and females relevant to the evolutionary context. In long-term situations for males, these problems included paternity uncertainty and selection of highly reproductive partners. For females, the main long-term problem was the search for an investing mate. Problems faced in short-term situations for males were partner number, sexual accessibility, identifying fertile females, and avoiding commitment and investment. For females, problems faced in short-term situations were immediate resource extraction, assessment of long-term mates, and the need for protection due to physical dimorphism. Behaviors that increased reproductive success were valuable, and thus subject to sexual selection. Some proposed adaptive behaviors included male promiscuity, male jealousy, and the value placed on resources by females. Although the focus on sex differences in numerous studies has led to many important discoveries, one negative consequence of this approach is that some people find it intuitively distasteful and end up dismissing evolutionary theory altogether. There is some strong opposition to the evolutionary approach. For example, radical alternatives that emphasize the social and cultural accounts of sex differences, such as Social Structural Theory (Eagly & Wood, 1999) and Biosocial Theory (Wood & Eagly, 2002), have been proposed. S. S. Hendrick and C. Hendrick (1992) suggested that neither the evolutionary nor the social/cultural models completely explain human mating. Evolutionary allies from other disciplines are critical of the traditional application of evolutionary theory to psychology (e.g., Gould, 1991). In a more moderate approach, de Waal (2002) explained that although the theory of evolution is frequently misapplied in psychology, it is still a necessary approach for the field because of its potential as a conceptual framework that can integrate the disconnected theories of human behavior. Evolutionary psychology’s theories reflect an examination of more sex differences than similarities. For example, traditional evolutionary mate preference studies give passing mention to sex similarities in mate preferences (Buss, 1985), referred to as species-typicality (Buss et al., 1990). Although evolutionary psychologists initially pursued the goals of identifying both sex similarities and differences in This project is based on a thesis paper by Robert Mather, conducted at Texas Tech University. I thank the members of the thesis committee, Darcy Reich and Clyde Hendrick, for their comments on the manuscript. Portions of this project were presented at the 2003 meeting of the Southwestern Psychological Association in New Orleans, LA.Address Correspondence to Robert Mather, Department of Psychology, 100 N. University Drive, University of Central Oklahoma, Edmond, 73034: e-mail: rmather@ucok.edu