演化心理學

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，演化心理學着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。

概要

演化心理學為生理辨認運作於"個體生理的物理適應。"演化心理學之目的為研究"個體的心理其自然演變的情感和認知適應。演化心理學就Steven Pinker而言是「不止一種單一理論，但為集大成之假說。」和「並且是一個關於心智，重點放在適應、基因級選擇的和心智區域modularity的特化演變理論。」演化心理學分析人類的大腦由很多功能機制組成,^[1]，中止心理適應或由天擇的演化認知機制設計。例如語言習得模組(language acquisition modules)、亂倫退避機制(incest avoidance mechanisms)、騙子偵測機制(cheater detection mechanisms)、智能於性-交配的特殊偏愛(sex-specific mating preferences)、搜尋食物機制(foraging mechanisms)、結盟夥伴關係(alliance-tracking mechanisms)、偵測覺知機制(agent detection mechanisms)等。演化心理學是根基在認知心理學(cognitive psychology)和演化生理學(evolutionary biology)(看社會生物學)。它是描寫行為環境(behavioral ecology)、人工智能(artificial intelligence)、遺傳學(genetics)、動物行為學(ethology)、人類學(anthropology)、考古學(archaeology)、生理學(biology)和動物學(zoology)。演化心理學是接近相似社會生物學(sociobiology)^[2]，但兩者間不同的關鍵重點在「物種個體差異範圍」(domain-specific)與「物種全體範圍」(domain-general)的機制。關於適合(生理上)(fitness)量的趨勢，重要的配錯理論(mismatch theory)為心理學而不是行為。然而很多的演化心理學爭辯的心智包括「物種個體差異範圍」和「物種全體範圍」兩者，主要在演化發展心理學(evolutionary developmental psychology|evolutionary developmental psychologists)。多數社會生理學研究現在發展在行為環境(behavioral ecology)的領域。^[3]

演化心理學由Michael Ghiselin在他1973年裏的學術文章中大略鑄造範圍。Jerome Barkow、Leda Cosmides和John Tooby普遍化了演化心理學的範圍，在他們1992年著作的《The Adapted Mind: Evolutionary Psychology and The Generation of Culture》裏有高度的影響。演化心理學嚮許多領域的研究，包括經濟、侵略、法律、精神病學、政治、文學和性。

演變心理學使用Nikolaas Tinbergen的(Tinbergen's four questions|four categories of questions)和動物行為的解釋。二個類別是在種類級；二個在個體級。種類級類別(經常叫做ultimate explanations)是

適應行為功能(例如適應adaptation)和
導致演化歷程這種功能(例如種系發展史)。

個體級類別是

個體發展(例如個體發生學)和
近似機制(例如腦解剖學和激素)。

演化心理學強調功能類別。

演化心理學的原則

演化心理學是洞察於現代演化理論、生物、認知心理學、人類學、經濟、電腦科學和古人類學所得出的一個混合學科。學科基於核心前提的基礎。相應於David Buss，卓越的田野研究，這些包括：

明顯行為取決於心理機制之下，觸發他們之活化作用的資訊處理設備被安置在腦，在與外部和內部觸發同時發生。
演化由選擇是唯一已知的原因，過程能創造這樣複雜有機機制。
演化的心理機制於功能上被專門研究解決復發在人深刻的演化時間之能適應的問題。
從環境中的資訊受個體適應影響於許多演化心理機制上選擇決定資訊處理。
人的心理學包括大量的專門功能演變機制，每個神經對上下輸入的特殊形式得到結合、協調和集成互相引起明顯行為。

同樣地，Leda Cosmides和John Tooby，二領域的創建者，提供這些演化心理學的五項基本原理的原則:

腦是一個物理的系統。它類似電腦。它的電路被設計於適當的引起您對環境情況的行為。
我們神經系統的電路由天擇設計解決我們的祖先面對在我們種類於演化歷史期間的問題。
知覺是意識冰山的一角；多數訊息進入您頭腦裏為掩藏於您。結果，您意識清楚之經驗可能誤引您於認知上，我們的電路比它真正地簡單。您體驗的多數問題像是容易解決卻是非常難解決--他們需要非常複雜的神經系統電路。
不同的神經系統電路被專門研究為解決不同的適合問題。
我們的現代頭骨安置一個石器時期的頭腦。^[4]

一般演化理論

Main article: Evolution

William Paley, drawing upon the work of many others, argued that organisms are machines designed to function in particular environments. Paley believed that this evidence of 'design' was evidence for a designer—God. Charles Darwin opposed Paley's argument that organisms are designed for particular environments by invoking the both Adam Smith and Malthus. He asserted that the supposed good design of organisms to environments was an accidental result of natural selection. The theory of natural selection, formulated in depth by Charles Darwin and Alfred Russel Wallace, provided a scientific account of the origins of functional design in the natural world.

Evolutionary psychology is rooted in evolutionary theory. It is sometimes seen 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,^[4] however many evolutionary biologists challenge the basic evolutionary premises of evolutionary psychology^[5].

Natural selection, a key component of evolutionary theory, involves three main ingredients:

Genetically based inheritance of traits - some traits are passed down from parents to offspring in genes,
Variation - heritable traits vary within a population (now we know that mutation is the source of this genetic variation),
Differential survival and reproduction - these traits will vary in how strongly they promote the survival and reproduction of their bearers.

Selection refers to the process by which environmental conditions "select" organisms with the appropriate traits to survive; these organisms will have such traits more strongly represented in the next generation. This is the basis of adaptive evolution. Darwin's great claim was that this "natural selection" was creative - it could lead to new traits and even new species, it was centred on individual survival, and it could explain the broad scale patterns of evolution.

Many traits that are selected for can actually hinder survival of the organism while increasing its reproductive opportunities. 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).

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 benefited 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 × 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.

Evolutionary Psychology

Evolutionary psychology borrows particular themes from evolutionary biology (outlined above), and adds these fundamental assumptions:

Existence of discrete psychological traits: Psychological aspects of humans (e.g. "spatial ability", "anxiety levels") are discrete traits,
Heritability of psychological traits: These traits have a genetic basis, they are inherited, and at some point in the evolutionary past have been components of genetic variation,
Adaptationism: These traits have been exposed to selection, and currently represent adaptations to some previous environment.

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 1970s, three very important middle-level evolutionary theories were contributed by Robert Trivers:

The theory of reciprocal altruism explains how altruism can arise amongst non-kin, as long as there is a sufficient probability of the recipient of the altruistic act reciprocating at a later date. The possibility was also noted by Trivers, later coined 'indirect altruism' by Richard Alexander, that reciprocation could be provided by third parties, raising the issue of social reputation. These theories have been criticized as example of "Just So stories" within evolutionary biology.

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 release 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, human females have a significantly higher obligatory investment in offspring than males do. (In some species, the opposite is true.) 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.

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.

Additional middle-level evolutionary theories used in EP include:

The Trivers-Willard hypothesis, which proposes that parents should invest more in the sex that gives them the greatest reproductive payoff (grandchildren) with increasing or marginal investment. 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.

r/K selection theory, which, in ecology, relates to the selection of traits in organisms that allow success in particular environments. r-selected species, (in unstable or unpredictable environments), produce many offspring, each of which is unlikely to survive to adulthood, while K-selected species, (in stable or predictable environments), invest more heavily in fewer offspring, each of which has a better chance of surviving to adulthood.
Evolutionary game theory, the application of population genetics-inspired models of change in gene frequency in populations to game theory.
Evolutionary stable strategy, which refers to a strategy, which if adopted by a population, cannot be invaded by any competing alternative strategy.

Evolved psychological mechanisms

Main article: Evolved psychological mechanisms

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

The 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,^[6] 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.^[7] 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.

Controversies

The application of evolutionary theory to animal behavior is uncontroversial. However, adaptationist approaches to human psychology have at times been contentious, with critics questioning the scientific nature of evolutionary psychology, and with more minor debates within the field itself. The history of debate from the evolutionary psychology perspective is covered in detail by Segerstråle (2000) and Alcock (2001); also see a recent overview of EP with rebuttals to critics in Tooby, J. & Cosmides, L. (2005). Conceptual foundations of evolutionary psychology.^[8]

The debates regarding the validity of evolutionary psychology have been regarded as occasionally quite vicious, with a strong ad hominem component. Some have suggested that the controversies would constitute a quiet debate over subtleties if the participants were less prone to caricaturing their opponents. A detailed discussion about the controversies can be viewed at the Evolutionary psychology controversy page.

Notes

^ evolutionary psychology Psyche Games. Accessed August 22 2007
^ Seltin, Melissa. (August 1988) The Evolution of Evolutionary Psychology: From Sociobiology to Evolutionary Psychology Accessed August 22 2007
^ 00265 Behavioral Ecology and Sociobiology Accessed August 22 2007
^ ^4.0 ^4.1 Cosmides、Leda和John Tooby。 January 13 1997年 Evolutionary Psychology: A Primer Accessed August 22 2007
^ See for examples, Gould, S.J. (2002) The Structure of Evolutionary Theory
^ CDC pdf
^ Öhman and Mineka 2001
^ 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

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 0-471-26403-2.

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

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

Wilson, E.O. (1975) Sociobiology: The New Synthesis

Wright, Robert (1995). The Moral Animal: Why We Are the Way We Are: The New Science of Evolutionary Psychology. ISBN 0-679-76399-6.

Alcock, John (2001). The Triumph of Sociobiology. Oxford: Oxford University Press.

Barkow, Jerome (Ed.). (2006) Missing the Revolution: Darwinism for Social Scientists. Oxford: Oxford University Press.

Clarke, Murray (2004). Reconstructing Reason and Representation. Cambridge: MIT Press.

Pinker, S. (1997). How the Mind Works. New York: W.W. Norton & Co.

Pinker, S. (2002). The Blank Slate: The Modern Denial of Human Nature. New York: Viking.

Richards, Janet Radcliffe (2000). Human Nature After Darwin: A Philosophical Introduction. London: Routledge.

Segerstrale, Ullica (2000). Defenders of the Truth: The Battle for Science in the Sociobiology Debate and Beyond. Oxford: Oxford University Press.

Miller, Geoffrey (2000). The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature. New York: Random House Inc.

External links

Introductory Reading

Evolutionary Psychology: A Primer
The Evolutionary Psychology FAQ
Human Behavior and Evolution Society(HBES) Introduction to the Field
On Scaffolds and Sweet Potatoes Introduction to Evolutionary Perspectives (registration required)
Books listed at the Human Behavior and Evolution Society.

Introductory peer-reviewed papers and chapters

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

Kennair, L. E. O. (2002). Evolutionary psychology: An emerging integrative perspective within the science and practice of psychology. Human Nature Review, 2, 17-61. Full text

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

Evolutionary Psychology Academic Societies

Human Behavior and Evolution Society (HBES)- International society of researchers who use modern evolutionary theory to discover human nature.
The International Society for Human Ethology (ISHE)- aims to promote ethological perspectives in the scientific study of humans worldwide.
The Association for Politics and the Life Sciences (APLS)- an international and interdisciplinary association of scholars, scientists, and policymakers concerned with evolutionary, genetic, and ecological knowledge and its bearing on political behavior, public policy and ethics.
Society for Evolutionary Analysis in Law
The New England Institute for Cognitive Science and Evolutionary Psychology