From The Art and Popular Culture Encyclopedia
Evolutionary psychology is a theoretical approach to psychology that attempts to explain 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 an adaptationist 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. Closely related fields are human behavioral ecology, dual inheritance theory, and sociobiology.
After his seminal work in developing theories of natural selection, Charles Darwin devoted much of his final years to the study of animal emotions and psychology. He wrote two books;The Descent of Man, and Selection in Relation to Sex in 1871 and The Expression of the Emotions in Man and Animals in 1872 that dealt with topics related to evolutionary psychology. He introduced the concepts of sexual selection to explain the presence of animal structures that seemed unrelated to survival, such as the peacock's tail. He also introduced theories concerning group selection and kin selection to explain altruism. Darwin pondered why humans and animals were often generous to their group members. Darwin felt that acts of generosity decreased the fitness of generous individuals. This fact contradicted natural selection which favored the fittest individual. Darwin concluded that while generosity decreased the fitness of individuals, generosity would increase the fitness of a group. In this case, altruism arose due to competition between groups. Darwin anticipated evolutionary psychology with this quote from the Origin of Species:
- In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation.
- -- Charles Darwin, The Origin of Species, 1859, p. 449.
According to Noam Chomsky, the founder of evolutionary psychology might have been Peter Kropotkin, who argued in his 1902 book Mutual Aid: A Factor of Evolution for the evolutionary benefits of behavioral traits related to mutual aid.
Post world war II
While Darwin's theories on natural selection gained acceptance in the early part of the 20th century, his theories on evolutionary psychology were largely ignored. Only after the second world war, in the 1950s, did interest increase in the systematic study of animal behavior. It was during this period that the modern field of ethology emerged. Konrad Lorenz and Nikolaas Tinbergen were pioneers in developing the theoretical framework for ethology for which they would receive a Nobel prize in 1973.
In 1975, E O Wilson built upon the works of Lorenz and Tinbergen by combining studies of animal behavior, social behavior and evolutionary theory in his book Sociobiology:The New Synthesis. Wilson included a chapter on human behavior. The specific chapter caused considerable controversy as it reignited the nature versus nurture debate.
E O Wilson argues that the field of evolutionary psychology is essentially the same as sociobiology. According to Wilson, the heated controversies surrounding Sociobiology:The New Synthesis, significantly stigmatized the term "sociobiology". Evolutionary psychology emerged as a more acceptable term in the 1980s that was not tainted by earlier controversies, and also emphasized that organisms are "adaptation executors" rather than "fitness maximizers" (which can help to explain maladaptive behaviors due to "fitness lags" given novel environmental changes). In addition, rather than focus primarily on overt behavior, EP attempts to identify underlying psychological adaptations (including emotional, motivational and cognitive mechanisms), and how these mechanisms interact with the developmental and current environmental influences to produce behavior.
Areas of research
Areas of research in evolutionary psychology can be divided into broad categories of adaptive problems that arise from the broader theory of evolution itself: survival, mating, parenting, kinship, and group living.
The Hunting Hypothesis might explain the emergence of human coalitions as a psychological mechanism. With men being the providers for the family, their lives depended on hunting wild game. They could not risk going about such an arduous task on their own. If they did it alone they risked not catching anything at all. Also, the meat would spoil if they caught a large animal and could not finish it on their own. Therefore, they hunted together with other men and shared their food. These human coalitions can be seen today. One form of evolutionary adaptiveness can be found in morning sickness in women during their first trimester.Highly acclaimed scientist Luke Gunn describes how 'Over thousands of years, women's bodies have adapted to the dangers that the environment may pose to the developing fetus when they eat something. Therefore, during this time many women experience disgust and even vomiting when eating certain foods which may be toxic to the fetus. Vomiting is the body's way of coping with the toxins in the environment and keeping them from reaching the child during this critical period when the vital organs are being formed. The function of this physiological reaction was to protect the fetus.'
Given that sexual reproduction is the means by which genes are propagated into future generations, sexual selection plays a large role in the direction of human evolution. Human mating, then, is of interest to evolutionary psychologists who aim to investigate evolved mechanisms to attract and secure mates. Several lines of research have stemmed from this interest, such as studies of mate selection, mate poaching, and mate retention, to name a few.
Much of the research on human mating is based on parental investment theory, which makes important predictions about the different strategies men and women will use in the mating domain (see above under "Middle-level evolutionary theories"). In essence, it predicts that women will be more selective when choosing mates, whereas men will not, especially under short-term mating conditions. This has led some researchers to predict sex differences in such domains as sexual jealousy, wherein females will react more aversively to emotional infidelity and males will react more aversively to sexual infidelity. This particular pattern is predicted because the costs involved in mating for each sex are distinct. Women, on average, should prefer a mate who can offer some kind of resources (e.g., financial, commitment), which means that a woman would also be more at risk for losing those valued traits in a mate who commits an emotional infidelity. Men, on the other hand, are limited by the fact that they can never be certain of the paternity of their children because they do not bear the offspring themselves. This obstacle entails that sexual infidelity would be more aversive than emotional infidelity for a man because investing resources in another man's offspring does not lead to propagation of the man's own genes.
Another interesting line of research is that which examines women's mate preferences across the ovulatory cycle. The theoretical underpinning of this research is that ancestral women would have evolved mechanisms to select mates with certain traits depending on their hormonal status. For example, the theory hypothesizes that, during the ovulatory phase of a woman's cycle (approximately days 10-15 of a woman's cycle), a woman who mated with a male with high genetic quality would have been more likely, on average, to produce and rear a healthy offspring than a woman who mated with a male with low genetic quality. These putative preferences are predicted to be especially apparent for short-term mating domains because a potential male mate would only be offering genes to a potential offspring. This hypothesis allows researchers to examine whether women select mates who have characteristics that indicate high genetic quality during the high fertility phase of their ovulatory cycles. Indeed, studies have shown that women's preferences vary across the ovulatory cycle. In particular, Haselton and Miller (2006) showed that highly fertile women prefer creative but poor men as short-term mates. Creativity may be a proxy for good genes. Research by Gangestad et al. (2004) indicates that highly fertile women prefer men who display social presence and intrasexual competition; these traits may act as cues that would help women predict which men may have, or would be able to acquire, resources.
Evolutionary Developmental Psychology
In evolutionary theory, what matters most is that individuals live long enough to reproduce and pass on their genes. So why do humans live so long after reproduction? Many evolutionary psychologists have proposed that living a long life improves the survival of babies because while the parents were out hunting, the grandparents cared for the young.
According to Paul Baltes, the benefits granted by evolutionary selection decrease with age. Natural Selection has not eliminated many harmful conditions and nonadaptive characteristics that appear among older adults, such as Alzheimer disease. If it were a disease that killed 20 year-olds instead of 70 year-olds this may have been a disease that natural selection could have destroyed ages ago. Thus, unaided by evolutionary pressures against nonadaptive conditions, we suffer the aches, pains, and infirmities of aging. And as the benefits of evolutionary selection decrease with age, the need for culture increases.
- Behavioural genetics
- Dual inheritance theory
- Ethnic nepotism
- Evolutionary developmental psychology
- Evolutionary educational psychology
- Evolutionary neuroscience
- Evolutionary Psychology Research Groups and Centers
- Gene-centered view of evolution
- Human behavioral ecology
- List of evolutionary psychologists
- Multiple discovery
- Outline of psychology