Evolutionary psychology is a theoretical approach to psychology that attempts to explain useful mental and psychological traits—such as memory, perception, or language—as adaptations, i.e., as the functional products of natural selection. The purpose of this approach is to bring the functional way of thinking about biological mechanisms such as the immune system into the field of psychology, and to approach psychological mechanisms in a similar way. In short, evolutionary psychology is focused on how evolution has shaped the mind and behavior. Though applicable to any organism with a nervous system, most research in evolutionary psychology focuses on humans. Evolutionary Psychology proposes that the human brain comprises many functional mechanisms, called psychological adaptations or evolved cognitive mechanisms designed by the process of natural selection. Examples include language acquisition modules, incest avoidance mechanisms, cheater detection mechanisms, intelligence and sex-specific mating preferences, foraging mechanisms, alliance-tracking mechanisms, agent detection mechanisms, and so on. Evolutionary psychology has roots in cognitive psychology and evolutionary biology. It also draws on behavioral ecology, artificial intelligence, genetics, ethology, anthropology, archaeology, biology, and zoology. Evolutionary psychology is closely linked to sociobiology, but there are key differences between them including the emphasis on domain-specific rather than domain-general mechanisms, the relevance of measures of current fitness, the importance of mismatch theory, and psychology rather than behaviour. Many evolutionary psychologists, however, argue that the mind consists of both domain-specific and domain-general mechanisms, especially evolutionary developmental psychologists. Most sociobiological research is now conducted in the field of behavioral ecology.