Psychological Inquiry, 19: 1–18, 2008 Copyright C  Taylor & Francis Group, LLC ISSN: 1047-840X print / 1532-7965 online DOI: 10.1080/10478400701774006 TARGET ARTICLE Is Evolutionary Psychology a Metatheory for Psychology? A Discussion of Four Major Issues in Psychology From an Evolutionary Developmental Perspective Annemie Ploeger, Han L. J. van der Maas, and Maartje E. J. Raijmakers Department of Psychology, University of Amsterdam, The Netherlands Evolutionary psychology has been proposed as a metatheoretical framework for psy- chology. We argue that evolutionary psychology should be expanded if it is to offer new insights regarding the major issues in psychology. Evolutionary developmental biology can provide valuable new insights into issues such as the domain-specificity of the human mind, the nature–nurture debate, stages in development, and the ori- gin of individual differences. Evolutionary developmental biology provides evidence for the hypotheses that domain-general and domain-specific abilities co-occur, that nature and nurture interact in a dynamic and nonadditive way, that stages occur in development, and that individual differences are the result of pleiotropic effects during development. Evolutionary psychology has been advanced as a metatheory for psychology, that is, as a unifying the- ory that can accommodate a diversity of facts and find- ings from all fields within psychology (Buss, 1995; Cosmides, Tooby, & Barkow, 1992). The general idea is that psychological characteristics (e.g., sex-specific mate preferences), like biological characteristics, have evolved over a long period and should be seen as adap- tations to the social and ecological circumstances that characterize human existence. The main tenet of evolu- tionary psychology is that the human mind comprises a collection of psychological adaptations, which arose through the process of natural selection. Another tenet is that humans have encountered distinct problems in different evolutionary periods and that the specific so- lutions to these problems have resulted in a multitude of functionally specialized, domain-specific mechanisms in the brain. This is known as the massive modularity assumption (Sperber, 1994). Since the rise of evolutionary psychology, many hypotheses about evolved psychological mechanisms have been derived and tested. Buss and Reeve (2003) pointed out that evolutionary psychologists have made many discoveries that had eluded other psychologists. These discoveries mostly concern issues related to so- cial exchange, mate choice, sexual behavior, relation- ship maintenance, and parental care. The interpretative framework and the possibilities of making new dis- coveries offered by the evolutionary perspective have certainly been fruitful. However, to function as a metatheory in psychology, evolutionary psychology should both identify impor- tant research questions that are often missed in other perspectives and address the current major issues in psychology. In this article, we consider the present contribution of evolutionary psychology to four major issues in psychology:  Does the human mind consist mostly of domain- specific abilities, or is the mind domain-general?  What is the influence of nature and nurture on the human mind?  Does development proceed in stages or gradually?  How do individual differences arise? As our point of departure, we examine three ap- proaches to evolutionary psychology. Tooby and Cos- mides (1992) presented a comprehensive framework for the field of evolutionary psychology. Buss (1995, 2003) presented a similar framework, in terms more suitable for a general audience. Pinker (1997), work- ing within this same framework, provided evolution- ary explanations for many psychological phenomena. To ease presentation, we refer to the general frame- work of these researchers as mainstream evolutionary 1