Evolutionary psychology

Biological: Behavioural genetics · Evolutionary psychology · Neuroanatomy · Neurochemistry · Neuroendocrinology · Neuroscience · Psychoneuroimmunology · Physiological Psychology · Psychopharmacology (Index, Outline)

Evolutionary psychology (abbreviated ev-psych or EP) proposes psychology can be better understood in light of evolution. Though 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 has roots in 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 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.

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. Evolutionary psychology has been applied to the study of many fields, including economics, aggression, law, psychiatry, politics, literature, and sex.

WVQMylecp58

EmbedVideo received the bad id "Brief introduction" for the service "youtube".

General evolutionary theory

Main article: Evolution

The idea that organisms are comprised of 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 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.

Evolutionary psychology is ultimately rooted in the basic theoretical principles that underlie the behavior of all living things: evolutionary theory. In fact, evolutionary psychology can be best conceived not simply as a sub-discipline of psychology but as a way in which evolutionary theory can be used as a meta-theoretical framework within which to examine the entire field of psychology. Evolutionary theory begins with the process of natural selection.

Natural selection involves three main ingredients:

Variation refers to a state in which there exists a variety of traits within a population.
Heritability refers to those traits that can be inherited via reproduction.
Selection refers to those heritable traits that remain in and spread through a population because those traits ultimately aid the organism in survival or reproduction.

Many traits that are selected for can actually hinder survival of the organism. Consider the classic example of the peacock's tail. It is metabolically costly, cumbersome, and essentially a "predator magnet." What the peacock's tail does do is attract mates. Thus, the type of selective process that is involved here is what Darwin called sexual selection. Sexual selection can be divided into two types:

Intersexual selection, which refers to the traits that one sex generally prefers in the other sex, (e.g. the peacock's tail).
Intrasexual competition, which refers to the competition among members of the same sex for mating access to the opposite sex, (e.g. two stags locking antlers).

Ultimately, no matter how much an organism reproduces, that organism dies, and it is genetic information that gets passed on from one generation to the next. Since it is genetic information that matters, there can also be selection pressures that favor the aid in survival and reproduction of an organism's genetic relatives, since they carry partial copies of varying degrees of an organism's genes. Such pressures are called kin selection.

Inclusive fitness

Inclusive fitness theory, which was proposed by William D. Hamilton in 1964 as a revision to evolutionary theory, is basically a combination of natural selection, sexual selection, and kin selection. It refers to the sum of an individual's own reproductive success plus the effects the individual's actions have on the reproductive success of their genetic relatives. General evolutionary theory, in its modern form, is essentially inclusive fitness theory.

Inclusive fitness theory resolved the issue of how "altruism" evolved. The dominant, pre-Hamiltonian view was that altruism evolved via group selection: the notion that altruism evolved for the benefit of the group. The problem with this was that if one organism in a group incurred any fitness costs on itself for the benefit of others in the group, (i.e. acted "altruistically"), then that organism would reduce its own ability to survive and/or reproduce, therefore reducing its chances of passing on its altruistic traits. Furthermore, the organism that benefitted from that altruistic act and only acted on behalf of its own fitness would increase its own chance of survival and/or reproduction, thus increasing its chances of passing on its "selfish" traits. Inclusive fitness resolved "the problem of altruism" by demonstrating that altruism can evolve via kin selection as expressed in Hamilton's rule:

cost < relatedness \times benefit

In other words, altruism can evolve as long as the fitness cost of the altruistic act on the part of the actor is less than the degree of genetic relatedness of the recipient times the fitness benefit to that recipient. This perspective reflects what is referred to as the gene-centered view of evolution and demonstrates that group selection is a very weak selective force. However, in recent years group selection has been making a comeback, (albeit a controversial one), as multilevel selection, which posits that evolution can act on many levels of functional organization, (including the "group" level), and not just the "gene" level.

Middle-level evolutionary theories

Middle-level evolutionary theories are theories that encompass broad domains of functioning. They are compatible with general evolutionary theory but not derived from it. Furthermore, they are applicable across species. During the early 1970's, three very important middle-level evolutionary theories were contributed by then Harvard graduate student, Robert Trivers:

The theory of reciprocal altruism demonstrates that altruism can arise amongst non-kin, as long as the recipient of the altruistic act reciprocates at a later date.

Parental investment theory refers to the different levels of investment in offspring on the part of each sex. For example, females in any species are defined as the sex with the larger gamete. In humans, females produce approximately one large, metabolically costly egg per month, as opposed to the millions of relatively tiny and metabolically cheap sperm that are produced each day by males. Females are fertile for only a few days each month, while males are fertile every day of the month. Females also have a nine month gestation period, followed by a few years of lactation. Males' obligatory biological investment can be achieved with one copulatory act. Consequently, females in our species have a significantly higher obligatory investment in offspring than males do, (though in some species, the opposite is true.) Because of this difference in parental investment between males and females, males and females face different adaptive problems in the domains of mating and parenting. Therefore, it is predicted that the higher investing sex will be more selective in mating, and the lesser investing sex will be more competitive for access to mates. Thus, sex differences are predicted to exist not because of maleness or femaleness per se, but because of different levels of parental investment.

The theory of parent-offspring conflict rests on the fact that even though a parent and his/her offspring are 50% genetically related, they are also 50% genetically different. All things being equal, a parent would want to allocate their resources equally amongst their offspring, while each offspring may want a little more for themselves. Furthermore, an offspring may want a little more resources from the parent than the parent is willing to give. In essence, parent-offspring conflict refers to a conflict of adaptive interests between parent and offspring.

However, if all things are not equal, a parent may engage in discriminative investment towards one sex or the other, depending on the parent's condition. Recall that females are the heavier parental investors in our species. Because of that, females have a better chance of reproducing at least once in comparison to males. Thus, according to the Trivers-Willard hypothesis, parents in good condition are predicted to favor investment in sons, and parents in poor condition are predicted to favor investment in daughters.

Products of the evolutionary process

There are three products of the evolutionary process:

Adaptations are heritable, species-typical traits that, (in terms of fitness costs), are "cost efficient" and function to solve problems related to one's inclusive fitness. An example would be the umbilical cord.

A by-product is a trait that has no adaptive value but is carried along by an adaptive trait. An example would be a belly button.

Noise refers to random effects resulting from chance variation in the genes, environment, or development. An example would be the shape of a belly button.

Evolved psychological mechanisms: the core of evolutionary psychology

Main article: Evolved psychological mechnisms

Evolutionary psychology is based on the belief 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 psychological mechanisms by understanding the survival and reproductive functions they might have served over the course of evolutionary history.

Evolutionary psychologists subdivide the concept of psychological mechanisms into two general categories:

Domain-specific mechanisms, which deal with recurrent adaptive problems over the course of human evolutionary history
Domain-general mechanisms, which deal with evolutionary novelty

The Environment of Evolutionary Adaptedness (EEA)

Main article: Environment of Evolutionary Adaptedness

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 psychological mechanism, one must similarly understand the properties of the environment that the psychological 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 psychological 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. (See Human evolution)

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.

How knowable is the EEA?

Some critics of evolutionary psychology 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, the critics contend, is thus confined to certainties about the past, such as pregnancies only occurring in women, and that humans lived in groups.

Many evolutionary psychologists argue that this criticism is based on a misunderstanding. Evolutionary psychologists argue that they 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, evolutionary psychologists posit that there are many environmental features that we can be sure played a part in our species' evolutionary history. They argue that our hunter-gatherer 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).

However, there also exists debate within evolutionary psychology about the nature of the EEA. Many evolutionary psychologists contend that many aspects of the EEA were not as consistent as other evolutionationay psychologists would argue. This argument is used, therefore, to support the notion that the mind consists of not only domain-specific psychological mechanisms but of domain-general ones as well, that deal with environmental novelty.

Falsifiability

Critics claim that many of the propositions of evolutionary psychology are not falsifiable and thus label it as a pseudoscience.

Evolutionary psychologists counter that this too is due to a fundamental misunderstanding. Evolutionary psychology, they argue, is a way of generating testable, (and thus falsifiable), hypotheses about the structure of the mind. Evolutionary psychologists contend that all of psychology makes predictions, (or assumptions), about the structure of the mind and that evolutionary psychology commits to a very specific causal relationship between the mind and the environment in which its design was selected, thus making evolutionary theory a source of highly specific, concrete, and falsifiable predictions.

Biology vs. environment

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. They argue that statements such as "biology vs. environment" and "genes vs. culture" amount to "false dichotomies." Evolutionary psychologists justify this claim by arguing that behavior results from an organism interacting with its environment. Psychological mechanisms, they argue, are created by genes, (which, in turn, were selected for by the evolutionary process),and those mechanisms help the organism negotiate its environment. Furthermore, they assert that many aspects of the environment, (e.g. culture and social institutions), are rested upon those mechanisms. In short, evolutionary psychologists argue that there is a bidirectional influence between things like "biology and environment" and "cognition and social processes."

Reductionism

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.

Ethical justification

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, they argue, 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). They further suggest that 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.

Evolutionary psychologists contend that 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, but it´s fair to say that Carl Sagan won the Pulitzer with the same idea (explayed twenty years before) in his book "Dragons of Eden".

Research data

Some commentators, like philosopher David Buller, agree with the general argument that the human mind has evolved over time but disagree with the specific claims evolutionary psychologists make. Buller has argued, among other things, that the so-called Cinderella Effect, the argument that there are gender differences with respect to sexual jealousy and the contention that the mind consists of thousands of modules, are unsupported by the available empirical evidence. [1]

An alternative to the "mental module" view of how human minds evolved is offered by cognitive psychologist Merlin Donald. He argues that over evolutionary time the mind has gained adaptive advantage from a general problem solver. Donald articulates this view in his book "A Mind So Rare: The Evolution of Human Consciousness" [2].

Image gallery

Bibliography & References

Barkow, Jerome; Cosmides, Leda; Tooby, John (1992) The Adapted Mind: Evolutionary Psychology and The Generation of Culture ISBN 0-19-510107-3.

Buss, David, ed. (2005) The Handbook of Evolutionary Psychology. ISBN 0471264032.

Buss, D.M. (2004). Evolutionary Psychology: The New Science of the Mind. Boston: Pearson Education, Inc.

Buss, D. M. (1995). Evolutionary psychology: A new paradigm for psychological science. Psychological Inquiry, 6, 1-30. Full text

Durrant, R., & Ellis, B.J. (2003). Evolutionary Psychology. In M. Gallagher & R.J. Nelson (Eds.), Comprehensive Handbook of Psychology, Volume Three: Biological Psychology (pp. 1-33). New York: Wiley & Sons. Full text

Ghiselin, Michael T. (1973). Darwin and Evolutionary Psychology. Science 179: 964-968.

Kenrick, D. T., Li, N. P., & Butner, J. (2003). Dynamical evolutionary psychology: Individual decision rules and emergent social norms. Psychological Review, 110, 3-28. Full text

Meyer, Wulf-Uwe (2002): Zur Geschichte der Evolutionären Psychologie (On History of EP, German)

Tooby, J. & Cosmides, L. (2005). Conceptual foundations of evolutionary psychology. In D. M. Buss (Ed.), The Handbook of Evolutionary Psychology (pp. 5-67). Hoboken, NJ: Wiley. Full text

External links

Human Behavior and Evolution Society (HBES)- The main academic society of evolutionary psychology researchers
Evolutionary Psychology: A Primer
The Evolutionary Psychology FAQ
Center for Evolutionary Psychology
What is Evolutionary Psychology? -A brief introduction to several areas in the field
Evolution and Human Behavior - The main academic journal of evolutionary psychology
Human Nature - Another academic journal devoted to EP
Evolutionary Psychology - An open access peer-reviewed journal
Human Nature Review
Controversies Surrounding Evolutionary Psychology
Harsh criticism of Evolutionary Psychology
Evolutionary psychology: Psychological aspects of human evolution
Evolutionary developmental psychology [3] & [4]
Evolutionary Psychology of Religion by Steven Pinker
Theory of (Evolutionary) Psychology (Documents No. 9 and 10 in English)

Interesting site covering evolutionaary and social psychology

This page uses Creative Commons Licensed content from Wikipedia (view authors).