Psicologia Evolucionária

[Ming Lee]

A frase chave:

"'It's a scientific revolution,' [a prominent supporter of evolutionary psychology] said of this newly named science, which sometimes seems an uncomfortable mixture of scientific method and cocktail party conversation." Carol K. Yoon

Um comentário estranho (á sacerdote) de um eminente Psicologo Evolucionário:

"The theory of natural selection is so elegant and powerful as to inspire a kind of faith in it--not blind faith, really.... But faith nonetheless; there is a point after which one no longer entertains the possibility of encountering some fact that would call the whole theory into question.
I must admit to having reached this point. Natural selection has now been shown to plausibly account for so much about life in general and the human mind in particular that I have little doubt that it can account for the rest." Robert Wright





A Critica:

"¶25 Three major claims define the core commitments of evolutionary psychology; each embodies a considerable strength and a serious (in one case, fatal) weakness:

l. Modularity. Human behavior and mental operations can be divided into a relatively discrete set of items, or mental organs. (In one prominent study, for example, authors designate a "cheater detector" as a mental organ, since the ability to discern infidelity and other forms of prevarication can be so vital to Darwinian success--the adaptationist rationale.) The argument for modularity flows, in part, from exciting work in neurobiology and cognitive science on localization of function within the brain--as shown, for example, in the precise mapping, to different areas of the cerebral cortex, of mental operations formerly regarded as only arbitrarily divisible by social convention (production of vowels and consonants, for example, or the naming of animals and tools).

¶26 Ironically, though, neurobiology and evolutionary psychology employ the concept of modularity for opposite theoretical purposes. Neurobiologists do so to stress the complexity of an integrated organ. Evolutionary psychology uses modularity to atomize behavior into a priori, subjectively defined, and poorly separated items (not known modules empirically demonstrated by neurological study), so that selective value and adaptive significance can be postulated for individual items, as the ultra-Darwinian approach requires.

2. Universality. Evolutionary psychologists generally restrict their study to universal aspects of human behavior and mentality, thereby explicitly avoiding the study of differences among individuals or groups. They argue that variations among individuals, and such groups as races and social classes, only reflect the influence of diverse environments upon a common biological heritage. In this sense, they argue, evolutionary psychology adopts a "liberal" position in contrast with the conservative implications of most previous evolutionary arguments about behavior, which viewed variation among individuals and groups as results of different, and largely unalterable, genetic constitutions.

¶27 I welcome much of this change; but, in one important respect, this new approach to universals and differences continues to follow the old strategy of finding an adaptationist narrative (often in the purely speculative or storytelling mode) to account for genetic differences built by natural selection. For the most-publicized work in evolutionary psychology has centered on the universality in all human societies of a particular kind of difference: the putative evolutionary reasons for supposedly universal behavioral differences between males and females.

3. Adaptation. Evolutionary psychologists claim that they have reformed the old adaptationism of sociobiology into a new and exciting approach. They will no longer just assume, they now say, that all prominent and universal behaviors must, ipso facto, be adaptive to modern humans in boosting reproductive success. They recognize, instead, that many such behaviors may be tragically out of whack with the needs of modern life, and may even lead to our destruction--aggressivity in a nuclear age, for example.

¶28 Again, I applaud this development. If this principle were advanced in conjunction with the recognition that a putative evolutionary origin does not necessarily imply an adaptive value at all, then evolutionary psychology could make a substantial advance in applying Darwinian theory to human behavior. But the advocates of evolutionary psychology proceed in the opposite direction by twisting the observation that the behavior of modern humans may not necessarily have adaptive value into an even more dogmatic, and even less scientifically testable, panadaptationist claim. Evolutionary universals may not be adaptive now, they say, but such behaviors must have arisen as adaptations in the different ancestral environment of life as small bands of hunter-gatherers on the African savannas--for evolutionary theory "means" a search for adaptive origins.

¶29 The task of evolutionary psychology then turns into a speculative search for reasons why a behavior that may harm us now must once have originated for adaptive purposes. To take an illustration proposed seriously by Robert Wright in The Moral Animal, a sweet tooth leads to unhealthy obesity today but must have arisen as an adaptation. Wright therefore states:


The classic example of an adaptation that has outlived its logic is the sweet tooth. Our fondness for sweetness was designed for an environment in which fruit existed but candy didn't.

This ranks as pure guesswork in the cocktail party mode; Wright presents no neurological evidence of a brain module for sweetness, and no paleontological data about ancestral feeding. This "just-so story" therefore cannot stand as a "classic example of an adaptation" in any sense deserving the name of science.




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¶30 Much of evolutionary psychology therefore devolves into a search for the so-called EEA, or "environment of evolutionary adaptation" that allegedly prevailed in prehistoric times. Evolutionary psychologists have gained some sophistication in recognizing that they need not postulate current utility to advance a Darwinian argument; but they have made their enterprise even more fatuous by placing their central postulate outside the primary definition of science--for claims about an EEA usually cannot be tested in principle but only subjected to speculation. At least an argument about modern utility can be tested by studying the current impact of a given feature upon reproductive success. Indeed, the disproof of many key sociobiological speculations about current utility pushed evolutionary psychology to the revised tactic of searching for an EEA instead.

¶31 But how can we possibly know in detail what small bands of hunter-gatherers did in Africa two million years ago? These ancestors left some tools and bones, and paleoanthropologists can make some ingenious inferences from such evidence. But how can we possibly obtain the key information that would be required to show the validity of adaptive tales about an EEA: relations of kinship, social structures and sizes of groups, different activities of males and females, the roles of religion, symbolizing, storytelling, and a hundred other central aspects of human life that cannot be traced in fossils? We do not even know the original environment of our ancestors--did ancestral humans stay in one region or move about? How did environments vary through years and centuries?

¶32 In short, evolutionary psychology is as ultra-Darwinian as any previous behavioral theory in insisting upon adaptive reasons for origin as the key desideratum of the enterprise. But the chief strategy proposed by evolutionary psychologists for identifying adaptation is untestable, and therefore unscientific. This central problem does not restrain leading disciples from indulging in reveries about the ubiquity of original adaptation as the source of revolutionary power for the putative new science. I detect not a shred of caution in this proclamation by Wright--embodying the three principal claims of evolutionary psychology as listed above:


The thousands and thousands of genes that influence human behavior--genes that build the brain and govern neurotransmitters and other hormones, thus defining our "mental organs" [note the modularity claim]--are here for a reason. And the reason is that they goaded our ancestors into getting their genes into the next generation [the claim for adaptation in the EEA]. If the theory of natural selection is correct, then essentially everything about the human mind should be intelligible in these terms [the ultra-Darwinian faith in adaptationism]. The basic ways we feel about each other, the basic kinds of things we think about each other and say to each other [note the claim for universality], are with us today by virtue of their past contribution to genetic fitness.

Wright's closing sermon is more suitable to a Sunday pulpit than a work of science:

The theory of natural selection is so elegant and powerful as to inspire a kind of faith in it--not blind faith, really.... But faith nonetheless; there is a point after which one no longer entertains the possibility of encountering some fact that would call the whole theory into question.

I must admit to having reached this point. Natural selection has now been shown to plausibly account for so much about life in general and the human mind in particular that I have little doubt that it can account for the rest.

¶33 This adaptationist premise is the fatal flaw of evolutionary psychology in its current form. The premise also seriously compromises--by turning a useful principle into a central dogma with asserted powers for nearly universal explanation--the most promising theory of evolutionary psychology: the recognition that differing Darwinian requirements for males and females imply distinct adaptive behaviors centered upon male advantage in spreading sperm as widely as possible (since a male need invest no energy in reproduction beyond a single ejaculation) and female strategies for extracting additional time and attention from males (in the form of parental care or supply of provisions, etc.). (In most sexually reproducing species, males generate large numbers of "cheap" sperm, while females make relatively few, "energetically expensive" eggs, and then must invest much time and many resources in nurturing the next generation.)

¶34 This principle of differential "parental investment" makes Darwinian sense and probably does underlie some different, and broadly general, emotional propensities of human males and females. But contrary to claims in a recent deluge of magazine articles, parental investment will not explain the full panoply of supposed sexual differences so dear to pop psychology. For example, I do not believe that members of my gender are willing to rear babies only because clever females beguile us. A man may feel love for a baby because the infant looks so darling and dependent, and because a father sees a bit of himself in his progeny. This feeling need not arise as a specifically selected Darwinian adaptation for my reproductive success, or as the result of a female ruse, culturally imposed. Direct adaptation is only one mode of evolutionary origin. After all, I also have nipples not because I need them, but because women do, and all humans share the same basic pathways of embryological development.

¶35 If evolutionary psychologists continue to push the theory of parental investment as a central dogma, they will eventually suffer the fate of the Freudians, who also had some good insights but failed spectacularly, and with serious harm imposed upon millions of people (women, for example, who were labeled as "frigid" when they couldn't make an impossible physiological transition from clitoral to vaginal orgasm), because they elevated a limited guide into a rigid creed that became more of an untestable and unchangeable religion than a science.




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¶36 Exclusive adaptationism suffers fatally from two broad classes of error, one external to Darwinian theory, the other internal. The external error arises from fundamental differences in principle and mechanism between, on the one hand, genetic Darwinian evolution and, on the other, human cultural change, which cannot be basically Darwinian at all. Since every participant in these debates, including Dennett and the evolutionary psychologists, agrees that much of human behavior arises by culturally induced rather than genetically coded change, giving total authority to Darwinian explanation requires that culture also work in a Darwinian manner. (Dennett, as discussed earlier, makes such a claim for cultural change in arguing for the "substrate neutrality" of natural selection.) But for two fundamental reasons (and a host of other factors), cultural change unfolds virtually in antithesis to Darwinian requirements.

¶37 First, topological: As the common metaphor proclaims, biological evolution builds a tree of life--a system based upon continuous diversification and separation. A lineage, after branching off from ancestors as a new species, attains an entirely independent evolutionary fate. Nature cannot make a new mammalian species by mixing 20 percent dugong with 30 percent rat and 50 percent aardvark. But cultural change works largely by an opposite process of joining, or interconnection, of lineages. Marco Polo visits China and returns with many of the customs and skills that later distinguish Italian culture. I speak English because my grandparents migrated to America. Moreover, this interdigitation implies that human cultural change needn't even follow genealogical lines--the most basic requirement of a Darwinian evolutionary process--for even the most distant cultural lineages can borrow from each other with ease. If we want a biological metaphor for cultural change, we should probably invoke infection rather than evolution.

¶38 Second, causal: As argued above, human cultural change operates fundamentally in the Lamarckian mode, while genetic evolution remains firmly Darwinian. Lamarckian processes are so labile, so directional, and so rapid that they overwhelm Darwinian rates of change. Since Lamarckian and Darwinian systems work so differently, cultural change will receive only limited (and metaphorical) illumination from Darwinism.

¶39 The internal error of adaptationism arises from a failure to recognize that even the strictest operation of pure Darwinism builds organisms full of nonadaptive parts and behaviors. Nonadaptations arise for many reasons in Darwinian systems, but consider only my favorite principle of "spandrels."

¶40 All organisms evolve as complex and interconnected wholes, not as loose alliances of separate parts, each independently optimized by natural selection. Any adaptive change must also generate, in addition, a set of spandrels, or nonadaptive byproducts. These spandrels may later be "co-opted" for a secondary use. But we would make an egregious logical error if we argued that these secondary uses explain the existence of a spandrel. I may realize someday that my favorite boomerang fits beautifully into the arched space of my living room spandrel, but you would think me pretty silly if I argued that the spandrel exists to house the boomerang. Similarly, snails build their shells by winding a tube around an axis of coiling. This geometric process leaves an empty cylindrical space, called an umbilicus, along the axis. A few species of snails use the umbilicus as a brooding chamber for storing eggs. But the umbilicus arose as a nonadaptive spandrel, not as an adaptation for reproduction. The overwhelming majority of snails do not use their umbilicifor brooding, or for much of anything.

¶41 If any organ is, prima facie, replete with spandrels, the human brain must be our finest candidate--thus making adaptationism a particularly dubious approach to human behavior. I can adopt (indeed I do) the most conventional Darwinian argument for why the human brain evolved to large size--and the nonadaptationist principle of spandrels may still dominate human nature. I am content to believe that the human brain became large by natural selection, and for adaptive reasons--that is, for some set of activities that our savanna ancestors could only perform with bigger brains.


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¶42 Does this argument imply that all genetically and biologically based attributes of our universal human nature must therefore be adaptations? Of course not. Many, if not most, universal behaviors are probably spandrels, often co-opted later in human history for important secondary functions. The human brain is the most complicated device for reasoning and calculating, and for expressing emotion, ever evolved on earth. Natural selection made the human brain big, but most of our mental properties and potentials may be spandrels--that is, nonadaptive side consequences of building a device with such structural complexity. If I put a small computer (no match for a brain) in my factory, my adaptive reasons for so doing (to keep accounts and issue paychecks) represent a tiny subset of what the computer, by virtue of inherent structure, can do (factor-analyze my data on land snails, beat or tie anyone perpetually in tic-tac-toe). In pure numbers, the spandrels overwhelm the adaptations.

¶43 The human brain must be bursting with spandrels that are essential to human nature and vital to our self-understanding but that arose as nonadaptations, and are therefore outside the compass of evolutionary psychology, or any other ultra-Darwinian theory. The brain did not enlarge by natural selection so that we would be able to read or write. Even such an eminently functional and universal institution as religion arose largely as a spandrel if we accept Freud's old and sensible argument that humans invented religious belief largely to accommodate the most terrifying fact that our large brains forced us to acknowledge: the inevitability of personal mortality. We can scarcely argue that the brain got large so that we would know we must die!

¶44 In summary, Darwin cut to the heart of nature by insisting so forcefully that "natural selection has been the main, but not the exclusive means of modification"--and that hard-line adaptationism could only represent a simplistic caricature and distortion of his theory. We live in a world of enormous complexity in organic design and diversity--a world where some features of organisms evolved by an algorithmic form of natural selection, some by an equally algorithmic theory of unselected neutrality, some by the vagaries of history's contingency, and some as byproducts of other processes. Why should such a complex and various world yield to one narrowly construed cause? Let us have a cast of cranes, some more important and general, others for particular things--but all subject to scientific understanding, and all working together in a comprehensible way. Why not admit for theory the same delight that Robert Louis Stevenson expressed for objects in his "Happy Thought":

The world is so full of a number of things,
I'm sure we should all be as happy as kings."

http://cogweb.ucla.edu/Debate/Gould.html

[Flavio Costa]

Miguel, sempre que você está com vontade de abrir outro tópico psicodélico sobre teísmo ou ciência você cria um novo personagem? Esse é o padrão de comportamento?

[Ming Lee]

É...
Tem a ver com o karma...

[Aurelio Moraes]

Voa etologia, voa...

[Ming Lee]

Voa etologia, voa...

O mundo da ciência do comportamento é muito esquisito.

A etologia antes era tudo. Depois veio a Sociobiologia, que era etologia na mesma mas dava mais atenção ao Darwinismo. Depois, a critica á Sociobiologia foi tão eficaz que a ela morreu, nascendo a ecologia comportamental e a Psicologia Evolucionária. Antes os Sociobiógos diziam que tudo o que somos está adaptado ao estilo de vida actual e tem a ver com a eficácia reprodutiva... agora os Psicologos Evolucionários dizem que não... as nossas faculdades mentais não estão adaptadas ao mundo actual mas sim ao EEA que é o ambiente adaptativo evolucionário (A savana do Pleistoceno). Ou seja, a Psicologia Evolucionária é a busca da EEA que já não existe e ninguém sabe direito como era. E depois as especulações sobre tal ambiente nem são sequer testáveis...

[Azathoth]

Miguelito, podemos conhecer minimamente o EEA correlacionado evidências de áreas como paleoantropologia, paleobiogeografia e paleoclimatologia.

[rapha...]

Voa etologia, voa...

[Ming Lee]

Miguelito, podemos conhecer minimamente o EEA correlacionado evidências de áreas como paleoantropologia, paleobiogeografia e paleoclimatologia.

Podemos?
Talvez em linhas muito gerais e mínimas... mas um processo como a seleção natural (que é descrito por Darwin, como onipresente e sempre atento) funciona de forma muito particular. Somando a isto contigêngias muito especificas, totalmente impossíveis de conhecer, e que quase de certeza são determinantes para a evolução do comportamento (pequenos efeitos podem gerar grandes mudanças... e esses efeitos são ambientais, genéticos, culturais), encontrar uma EEA pode ser uma missão impossível. Mas em linhas gerais podemos inventar muitas histórias plausíveis. É uma crise de fartura...