Evolutionary psychology (or EP) proposes that human and primate cognition and behavior can be better understood in light of human and primate evolutionary history. Specifically, EP proposes the primate brain comprises many functional mechanisms, called psychological adaptations or evolved psychological mechanisms (EPMs), that evolved by natural selection to benefit the survival and reproduction of the organism. These mechanisms are universal in the species, excepting those specific to sex or age. Uncontroversial EPMs include vision, hearing, memory, and motor control. More controversial examples include differences in male and female mating preferences and strategies, temperaments and cognitive abilities, incest avoidance mechanisms, cheater detection mechanisms and capture-bonding.

The main sources of evolutionary psychology are cognitive psychology, genetics, ethology, anthropology, biology, and zoology. The term evolutionary psychology was probably coined by Ghiselin in his 1973 article in Science. Leda Cosmides and John Tooby popularized the term in their highly influential 1992 book The Adapted Mind: Evolutionary Psychology and The Generation of Culture (ISBN 0195101073).

Evolutionary psychology has been applied to the study of many fields, including economics, aggression, law, psychiatry, politics, literature, and sex. Evolutionary psychology is closely linked to the field of sociobiology, but there are key differences between them including the emphasis on domain-specific rather than domain-general faculties, the relevance of measures of current fitness, the importance of mismatch theory, and psychology rather than behaviour.

Theoretical background: William Paley, drawing upon the work of many others, argued that organisms are machines designed to function in particular environments. This idea is the foundation of modern medicine and biology. Prior to Darwin and Wallace, it was thought that the design evident in organisms was evidence for God. Darwin and Wallace's theory of evolution by natural selection provided a scientific account of the origins of function.

Evolutionary psychology is based on the presumption that, just like hearts, lungs, livers, kidneys, and immune systems, cognition has functional structure that has a genetic basis, and therefore has evolved by natural selection. Like other organs and tissues, this functional structure should be universally shared amongst humans and should solve important problems of survival and reproduction. Evolutionary psychologists seek to understand cognitive processes by understanding the survival and reproductive functions they might serve.

Controversies:
Animal behavior studies have long recognized the role of evolution; the application of evolutionary theory to human psychology, however, is controversial. There are many families of criticism of the idea.

Some claim that because little is known about the evolutionary context in which humans developed (including population size, structure, lifestyle, eating habits, habitat, and more), there is little basis on which evolutionary psychology may operate. Most EP research is thus confined to certainties about the past, such as pregnancies only occuring in women, and that humans lived in groups. Others believe this criticism is based on a misunderstanding. Evolutionary psychologists use knowledge of the environment of evolutionary adaptedness to generate hypotheses regarding possible psychological adaptations and subsequently these hypotheses can be tested and evaluated against the empirical evidence in just the same way that any other hypothesis generated from any other theoretical perspective can be assessed. Furthermore, there are many environmental features that we can be sure played a part in our species evolutionary history. Our ancestors most certainly dealt with predators and prey, food acquisition and sharing, mate choice, child rearing, interpersonal aggression, interpersonal assistance, diseases and a host of other fairly predictable challenges that constituted significant selection pressures.

Critics claim that many of its propositions are not falsifiable, and thus label it as a pseudoscience. This is again due to a fundamental misunderstanding; Evolutionary Psychology is a way of generating testable (and thus falsifiable) hypotheses about the structure of the mind. All of psychology makes predictions (or assumptions) about the structure of the mind. Because it commits to a very specific causal relationship between the mind and the environment in which its design was selected, evolutionary psychology is in fact a source of highly specific, concrete, and falsifable predictions.

Some studies have been criticized for their tendency to attribute to evolutionary processes elements of human cognition that may be attributable to social processes (e.g. preference for particular physical features in mates). This criticism shows a fundamental misunderstanding as well. All of our psychology is made possible by highly-improbably, elegantly structured computations (as the folks in AI trying to build functional robots have discovered). That is, all 'social processes' are causally related to evolutionary processes. The real issue is not whether or not any aspects of our experience (or phenomenology) are due to evolutionary processes. All are; an uninteresting answer. Rather, the interesting questions is: What functional systems make social processes possible? And, what is their developmental course? Psychology knows next to nothing about either question for any system who's function is not intuitive. Evolutionary Psychology allows psychologists to gain ground on many more likely functions and thus learn more about many more systems, including the hundreds if not thousands that enable 'social processes'.

Some alternatives to evolutionary psychology maintain that elements of human behaviour are irreducible to their component parts. By way of illustration, in the work of the Peter Hobson, human consciousness is identified as the product principally of intersubjective learning, albeit on a platform of emotional tools provided by human nature. As a social process, such a construction of minds would not be describable in the cellular components of individual organisms. See Daniel Dennett for an elegant handling of this caricature of science (called greedy reductionism), which is not characteristic of any sophisiticated philoposophy of science, including a science of psychology informed by evolutionary biology.

Some people worry that evolutionary psychology will be used to justify harmful behavior, and have at times tried to suppress its study. They give the example that a husband may be more likely to cheat on his wife, if he believes his mind is evolved to be that way.

Evolutionary psychologists respond by saying that like any other branch of science, evolutionary psychologists only claim to state what is, and not what ought to be. In fact, knowing how something works is the first step in fixing it if its broke (e.g. all of medical science), or changing how it works if we decide that is the right thing to do (e.g. if the system that 'makes' men promiscous is understood, and men understand why it exists- not for their happiness, not because it is right or moral, but because of the blind causal process of natural selection, men can become better consumers of their own consciousness, or we may even decide as a world community to offer interventions). Understanding how cancer works in no way condones its existence.

Well-known evolutionary psychologists:
In addition to Leda Cosmides and John Tooby, some of the best-known authors in the field are:

• David Buss
• Martin Daly
• Richard Dawkins
• Robin Dunbar
• Steven W. Gangestad
• David C. Geary
• Sarah Blaffer Hrdy
• Kevin B. MacDonald
• Robert Kurzban
• Geoffrey Miller
• Steven Pinker
• Matt Ridley
• Donald Symons
• Robert Trivers
• Margo Wilson
• Robert Wright