Evolutionary psychology

Evolutionary psychology (abbreviated ev-psych or EP) proposes that animal psychology can be better understood in light of evolution. Although EP is applicable to any organism with a nervous system, most EP research focuses on humans.

Specifically, EP proposes the brain comprises many functional mechanisms, called psychological adaptations or evolved psychological mechanisms (EPMs), that evolved by natural selection. Uncontroversial examples of EPMs include vision, hearing, memory, and motor control. More controversial examples include incest avoidance mechanisms, cheater detection mechanisms, and sex-specific mating preferences, mating strategies, and spatial cognition. Most evolutionary psychologists argue that EPMs are universal in a species, excepting those specific to sex or age.

Evolutionary psychology is best understood as a synthesis of cognitive psychology and evolutionary biology. It also draws heavily on behavioral ecology, artificial intelligence, genetics, ethology, anthropology, archeology, 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 faculties, the relevance of measures of current fitness, the importance of mismatch theory, and psychology rather than behaviour. Most sociobiological research is now conducted in the field of behavioral ecology.

The term evolutionary psychology was probably coined by Ghiselin in his 1973 article in Science. Jerome Barkow, 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.

Theoretical background
The idea that organisms comprise a number of parts that serve different functions (i.e., living things are, in some sense, machines) goes back at least to Aristotle. This idea is the foundation of modern medicine and biology. William Paley, drawing upon the work of many others, argued convincingly that organisms are machines designed to function in particular environments. Paley believed that this evidence of 'design' was evidence for a designer -- God. Darwin appears to have been impressed with Paley's argument that organisms are designed for particular environments. The theory of evolution by natural selection, created by Darwin and Wallace, provided a scientific account of the origins of functional design in the natural world that did not invoke a supernatural designer. (See also: sexual selection, kin selection, inclusive fitness, gene-centric view of evolution, parental investment, parent-offspring conflict, reciprocal altruism)

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 a species, 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 have served over the course of evolutionary history.

The Environment of Evolutionary Adaptedness (EEA)
In order to understand the design and function of any mechanism, it is necessary to correctly identify the 'environment' the mechanism is intended to interact with. It would be difficult to understand the design of a pipe wrench, for example, without understanding the properties of pipes and pipe-fittings. This argument also applies to evolved mechanisms in the living world. It would be difficult, if not impossible, to understand the function of the lungs without understanding the properties of a gaseous oxygen atmosphere, or to understand the immune system without understanding the properties of pathogens. The environment that a mechanism evolved to interact with is termed the EEA of that mechanism.

EP argues that in order to understand an evolved cognitive mechanism, one must similarly understand the properties of the environment that the cognitive mechanism evolved to interact with. Sunlight is an essential aspect of the EEA of vision, for example. For another example, the fact that women got pregnant and men did not is an essential aspect of the EEA of human mating preferences.

The EEA is not a single time or place. Rather, it is adaptation-specific. The EEA of the lungs is different from the EEA of vision is different from the EEA of the immune system is different from the EEA of mating preferences.

The term 'EEA' was coined by John Bowlby of attachment theory fame. In the environment in which ducks evolved, the first moving being that a duckling was likely to see was its mother. A cognitive mechanism that evolved to form an attachment to the first moving being would therefore properly function to form an attachment to the mother. In novel environments, however, the mechanism can malfunction by forming an attachment to a dog or human instead. It is an important prediction of EP that human psychology will similarly exhibit some such mismatches. One convincing example is the fact that although cars kill over 40,000 people in US annually, whereas spiders and snakes kill only a handful, people nonetheless much more readily learn fear of spiders and snakes than they do fear of cars, guns, electric outlets, and other novel dangers. The most likely explanation is that spiders and snakes were a real threat to human ancestors, whereas cars and other novel dangers were not. There is thus a mismatch between our evolved fear learning psychology and the modern environment.

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 occurring 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. (For a strong outline of the current state of all our concrete knowledge in this area, see: Mithen, Steven. After The Ice: A Global Human History 20000-5000 BC. Harvard Uni. Press, 2004).

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. Evolutionary psychology commits to a very specific causal relationship between the mind and the environment in which its design was selected, making it a source of highly specific, concrete, and falsifiable 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). Evolutionary psychologists respond that many traits have been shown to be universal in humans and that social processes are related to evolutionary 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 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 sophisticated philosophy 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 people may be more likely to cheat on their spouse if they believe their mind evolved to be that way.

Evolutionary psychologists respond by saying that they only state what is, not what ought to be. Knowing how something works is the first step in fixing it if it's broken, or changing how it works (if we should is a decision commonly left to philosophers). If people understand the system that 'makes' them promiscuous - not for their happiness, not because it is right or moral, but because of the blind causal process of natural selection - they can become better consumers of their own consciousness, and other people may be able to use this understanding to intervene and change their behaviour.

Understanding evolutionary psychology does not entail taking a moral viewpoint on people's behaviour, any more than understanding how cancer works condones its existence. (see naturalistic fallacy)

A recent hypothesis about the nature of the human condition (our capacity for good and evil) is based on the approach of evolutionary biology. Jeremy Griffith asks the question “what happened in human evolution when the intellect evolved to the level where it could take control from the instincts”. This hypothesis is explored in a controversial book entitled A Species in Denial