The goal of cross-cultural psychology to identify and explain similarities and differences in the behavior of individuals in different cultures requires linking human behavior to its context (Cole, Meshcheryakov & Ponomariov, 2011). In order to specify this relation, the focus is usually on the sociocultural environment and how it interacts with behavior. Since crosscultural psychology also deals with the evolutionary and biological bases of behavior, this focus on culture has regularly led to an unbalanced view (Berry, Poortinga, Breugelmans, Chasiotis & Sam, 2011). Too often, biology and culture are seen as opposites: what is labeled as cultural is not biological and what is labeled as biological is not cultural (Chasiotis, 2010, 2011a). This article will first introduce the central concepts of natural and sexual selection, adaptation, and the epigenetic (open) genetic processes in evolutionary biology, and indicate their psychological implications. It will then argue that biology and culture are intricately related. Finally, empirical evidence from diverse psychological research areas will be presented to illustrate why the study of the evolutionary basis is as essential as the analysis of the sociocultural context for the understanding of behavior. Due to space restrictions, cultural transmission will be the only research area which is addressed in more detail (more examples of evolutionary approaches in intelligence, personality, and behavior genetics and their implications for cross-cultural research can be found on the website accompanying Berry et al., 2011; see also further readings section). Creative Commons License This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. This article is available in Online Readings in Psychology and Culture: http://scholarworks.gvsu.edu/orpc/vol9/iss1/1 The goal of cross-cultural psychology to identify and explain similarities and differences in the behavior of individuals in different cultures requires linking human behavior to its context (Cole, Meshcheryakov & Ponomariov, 2011). In order to specify this relation, the focus is usually on the sociocultural environment and how it interacts with behavior. Since cross-cultural psychology also deals with the evolutionary and biological bases of behavior, this focus on culture has regularly led to an unbalanced view (Berry, Poortinga, Breugelmans, Chasiotis & Sam, 2011). Too often, biology and culture are seen as opposites: what is labeled as cultural is not biological and what is labeled as biological is not cultural (Chasiotis, 2010, 2011a). This article will first introduce the central concepts of natural and sexual selection, adaptation, and the epigenetic (open) genetic processes in evolutionary biology, and indicate their psychological implications. It will then argue that biology and culture are intricately related. Finally, empirical evidence from diverse psychological research areas will be presented to illustrate why the study of the evolutionary basis is as essential as the analysis of the sociocultural context for the understanding of behavior. Due to space restrictions, cultural transmission will be the only research area which is addressed in more detail (more examples of evolutionary approaches in intelligence, personality, and behavior genetics and their implications for cross-cultural research can be found on the website accompanying Berry et al., 2011; see also further readings section). Basic concepts of evolutionary biology