演化心理學
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演化心理學，（簡稱ev-psych或 EP）是一種企圖解釋人類「有用」的精神及心理特點——如記憶、知覺、語言和適應——的一種心理學研究理論，也就是，作為自然選擇的功能產物。這種研究方法的目的是帶出機能心理學那種將例如免疫系統般的生物機制放進心理學範籌的思考方法，以及用類似方法探討心理學機制。簡短來說，演化心理學著眼於演化如何把思維定型。儘管此理論適用於任何擁有神經系統的生物，大部份演化心理學的研究集中於人類身上。 Because of this difference in parental investment between males and females, the sexes 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, differences in behaviour between sexes is predicted to exist not because of maleness or femaleness per se, but because of different levels of parental investment.
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.
[编辑] Products of the evolutionary processAll biological traits are products of the evolutionary process. Adaptationist methods, including evolutionary psychology, attempt to distinguish between adaptations and traits produced as by-products of adaptation.
Natural selection is not the only evolutionary process that can change gene frequencies and produce novel traits. Genetic drift, or noise, refers to random effects resulting from chance variation in the genes, environment, or development. An example would be dry earwax in humans. Unlike natural selection, genetic drift does not produce complex, functionally designed adaptations. [编辑] Evolved psychological mechanisms: the core of evolutionary psychology
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:
[编辑] The environment of evolutionary adaptednessThe term environment of evolutionary adaptedness, often abbreviated EEA, was coined by John Bowlby as part of attachment theory. It refers to the environment to which a particular evolved mechanism is adapted. More specifically, the EEA is defined as the set of historically recurring selection pressures that formed a given adaptation, as well as those aspects of the environment that were necessary for the proper development and functioning of the adaptation. In the environment in which ducks evolved, for example, attachment of ducklings to their mother had great survival value for the ducklings. Because 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. The genus Homo, which includes modern humans, appeared between 1.5 and 2.5 million years ago, a time that roughly coincides with the start of the Pleistocene 1.8 million years ago. Because the Pleistocene ended a mere 12,000 years ago, most human adaptations either newly evolved during the Pleistocene, or were maintained by stabilizing selection during the Pleistocene. Evolutionary psychology therefore proposes that the majority of human psychological mechanisms are adapted to reproductive problems frequently encountered in Pleistocene environments. In broad terms, these problems include those of growth, development, differentiation, maintenance, mating, parenting, and social relationships. To properly understand human mating psychology, for example, it is essential to recognize that in the EEA (as now) women got pregnant and men did not. If humans are mostly adapted to Pleistocene environments, then some psychological mechanisms should occasionally exhibit “mismatches” to the modern environment, similar to the attachment patterns of ducks. One example is the fact that although about 30,000 people are killed with guns in the US annually (CDC pdf), whereas spiders and snakes kill only a handful, people nonetheless learn to fear spiders and snakes about as easily as they do a pointed gun, and more easily than an unpointed gun, rabbits or flowers (Öhman and Mineka 2001). A potential explanation is that spiders and snakes were a threat to human ancestors throughout the Pleistocene, whereas guns, rabbits and flowers were not. There is thus a mismatch between our evolved fear learning psychology and the modern environment. In sum, evolutionary psychology argues that to properly understand the functions of the brain one must understand the properties of the environment in which the brain evolved. [编辑] ControversiesAnimal 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. [编辑] How knowable is the early environment (EEA)?Some critics of evolutionary psychology claim that because little is known about the Pleistocene, 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. 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.[1] 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 evolutionary psychologists would argue. This argument is used 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. [编辑] Too many alternative hypothesesCritics claim that many valid hypotheses, including contradictory ones, can be drawn from the same evolutionary principles. Evolutionary psychology can predict many, or even all, behaviours for a given situation, including contradictory ones. Therefore many human behaviours will always fit some hypotheses. The central paradigm of evolutionary psychology is impossible to prove, and the predicting power of evolutionary psychology is doubtful. For example, kin selection predicts that humans will be altruistic toward relatives in proportion to their relatedness, while reciprocal altruism predicts that we will be altruistic toward people from whom we can expect altruism in the future (not strangers). However, altruism towards a complete stranger fits the handicap principle. Thus altruism toward every class of person fits some well-known hypothesis. This doesn't seem to give us any way to predict how a human will act in a given situation. Evolutionary psychologists respond that their discipline is not primarily concerned with explaining the behavior of specific individuals, but rather broad categories of human behaviors across societies and cultures. It is the search for species-wide trends in behavior that distinguishes evolutionary psychology from cultural or social explanations. Thus hypotheses will attempt to explain contradictory human behavior because human behavior is often contradictory. [编辑] FalsifiabilityCritics claim that many of the propositions of evolutionary psychology are not falsifiable. It is not possible to conduct definitive experiments on humans on an evolutionary timescale. This criticism in particular is common and often refers to evolutionary psychological theories as just-so stories. The methods that evolutionary psychologists actually use for testing include comparing different species, comparing males and females, comparing individuals within a species and comparing the same individuals in different contexts. Their sources of data for testing evolutionary hypotheses include archeological records, data from hunter-gatherer societies, observations, self-reports, life-history data and public records, and human products. Source: Evolutionary Psychology: The New Science of the Mind by David Buss. [编辑] Biology versus environmentSome 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." [编辑] ReductionismEvolutionary Psychology is grounded on the theory that fundamentally our psychology is based on biology, the composition of our brains. This is a form of reductionism, a research philosophy according to which the nature of complex things can be understood in terms of simpler or more fundamental things (i.e. reduced). Importantly, reductionism as applied to consciousness and the brain, comes in various forms, some of which may be more philosophically problematic for Evolutionary Psychology than others. It is a long-standing matter of debate in Philosophy of Mind as to whether Mental States are identical with physical Brain States, or what sort of relation could be said to hold between the two. However, it can be argued that Evolutionary Psychology is not committed to any particular answer to this question, being potentially compatible with Supervenience, Interactionism, Epiphenomenalism and both Token and Type physicalism, for example. Nevertheless, some people remain sceptical about any form of reduction from psychology to biology, and question its validity as an approach. Why then, is the accusation of reductionism commonly used as a criticism of Evolutionary Psychology, and not say, as a criticism of Neuropsychopharmacology? (A discipline in which an implicit premise as regards psychology is that all states of mind, including both normal and drug-induced altered states, and diseases involving mental or cognitive dysfunction, have a neuro-chemical basis at the fundamental level.) The reason is that Evolutionary Psychology is a controversial field in itself, and to quote Richard Dawkins: "'reductionism', like sin, is one of those things only mentioned by people who are against it." The Blind Watchmaker, 1986 p.13. Here Dawkins makes a distinction between "direct" and "hierarchical" reductionism: organisms can be described in terms of DNA, DNA in terms of atoms, atoms in terms of sub-atomic particles etc; but knowledge of sub-atomic particles will not directly explain animal or human behavior, nevertheless, one can make adequate explanations and predictions at a higher levels. [编辑] Issues in EthicsThat human psychology may be determined by our biology, which is shaped by our evolutionary past, is an important idea for those involved in Ethics. The implications are as broad and varied as the field of Ethics itself however, but generally, it is thought that Evolutionary Psychology describes factors which limit our free will, in that it can be seen to imply that we behave in ways in which we are ‘naturally inclined’. Evolutionary Psychology is not in itself of course a theory of Ethics, it merely states what is, not what ought to be, but this idea of ‘natural inclination’ is a recurring theme in Ethics, arising not just out of Evolutionary Psychology, but almost all of the Social Sciences. To quote J. Mizzoni from his article Ruse's Darwinian Ethics and Moral Realism: “There are some moral philosophers (e.g., Thomas Nagel) who believe that evolutionary considerations are irrelevant to a full understanding of the foundations of ethics. Other moral philosophers (e.g., J.L. Mackie) tell quite a different story. They hold that the admission of the evolutionary origins of human beings compels us to concede that there are no foundations for ethics.” As we can see, the matter is subject to debate, some believing that evolutionary considerations are correct and necessary, others that they are incorrect and a form of the naturalistic fallacy, and others indeed that they are morally harmful whether correct or not. This idea of the supposed moral harm done by bringing together the Social Sciences and Ethics is arguably where the greatest controversy lies. [编辑] Empirical evidenceSome 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] (But see Daly and Wilson's response to Buller) 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]. Another criticism regarding empirical evidence is a perceived lack of cross-cultural proofs. Many empirical studies come from a single culture. In these cases it is unknown if discoveries hold across all cultures. [编辑] Some references for rebuttals to criticisms of evolutionary psychology
[编辑] References
Also see books listed at the Human Behavior and Evolution Society. [编辑] See also
[编辑] External links
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