What is evolutionary psychology?
Autor: COLARES, K. Ψ | Publicado: 2012-01-18T04:17:00-08:00

...é importante conhecer novas abordagens...In the three and a half centuries since William Harvey  proved that the purpose of the heart is to pump blood, physiologists  have revealed the functional organization of the body in blinding  detail. Their discoveries demonstrate beyond question that the structure  of the body serves survival and reproduction. Further, there is near  unanimity among biologists that this functional structure is a product  of natural selection. In our century, psychologists have developed  powerful techniques that conclusively demonstrate that cognition, too,  has structure. Evolutionary psychologists are betting that cognitive  structure, like physiological structure, has  been designed by natural  selection to serve survival and reproduction.    Evolutionary psychology focuses on the evolved properties of  nervous systems, especially those of humans. Because virtually all  tissue in living organisms is functionally organized, and because this  organization is the product of evolution by natural selection, a major  presumption of evolutionary psychology is that the brain, too, is  functionally organized, and best understood in evolutionary perspective.  It is clear that the body is composed of a very large number of parts,  and that each part is highly specialized to perform a specific function  in service of the survival and reproduction of the organism. Using the  body as a model for the brain, it is a fair guess that the brain, too,  is composed of one or more functional parts, each of which is also  specialized to facilitate the survival and reproduction of the organism  (we'll get to genes in a bit). Thus, according to evolutionary  psychology, neural tissue is no different from any other tissue: it is  functionally organized to serve survival and reproduction. This is the  foundational assumption of evolutionary psychology. Because vision,  hearing, smell, pain, and motor control are indisputable functions of  the nervous system that clearly have utility for survival and  reproduction, this assumption has a high degree of face validity.  Further, these examples suggests that the brain may best be conceived  not as an organ with a single function, but rather as composed of a  large, and potentially vast number of functional parts. Evolutionary  biologists refer to the functional components of organisms as  'adaptations'. Evolutionary psychologists often refer to brain functions  as psychological adaptations, although they are not qualitatively  different from other adaptations.   The functional organization of the body has been elucidated  primarily by the direct examination of morphology. A detailed analysis  of the structure and composition of our organs and tissues has resulted  in an excellent understanding of their purpose. Unfortunately, this has  not been the case with the brain. The gross morphology of the brain  appears to have little connection with its functional properties.  Although we have a fair understanding of nerve cells--the primary  constituents of neural tissue--the properties of the brain clearly come  from higher order assemblages of such cells, not just the cells  themselves. This is just as true of organs like the heart as it is of  the brain. Because nerve cells can rapidly change state (e.g., their  firing rate), because such state-changes involve little energy, and  because they can be well insulated from their neighbors, it is possible  for a nerve cell to be in one state, whereas some of its close neighbors  may be in completely different states. This is in marked contrast to,  say, muscle cells. If one muscle cell is involved in a contraction, then  nearby cells almost certainly are as well. Neural tissue is quite  different. Even the individual states of nerve cells in a network depend  critically on the topology of the network itself. Further, assemblages  that are actually distinct may have a complex three-dimensional  distribution that can be very difficult to untangle. These properties of  neural tissue make it exceedingly difficult to "see" the morphology of  neural assemblages--with few exceptions, the network topology of  virtually our entire brain is currently "invisible." It exists at a  scale above the individual cell, but well below that which can be teased  apart with any imaging technology currently available. Until recent  decades, much of our immune system was similarly "invisible."   Evolutionary psychology offers one way around this technological  limitation. If researchers had a sound basis for proposing brain  functions a priori, they could then seek indirect evidence that brains  in fact have these functional properties. Philosophers and scientists  had long wondered why living things are made up of an amazing array of  beautifully designed mechanisms, an organization which non-living things  completely lack. Why is it that entities that reproduce manifest  overwhelming evidence of design, but entities that don't reproduce are  utterly devoid of the same? As Darwin and Wallace first perceived, the  association of reproduction and design is not accidental. Evolution by  natural selection is currently accepted as the only process whereby  entities can acquire functional properties. Functional organization is  the consequence of the reproductive feedback that characterizes natural  selection. If a population of reproducing entities (hereafter organisms)  varies in some trait, if the variations can be passed on to offspring,  and if, as a consequence of possessing a particular variant, an organism  produces more offspring on average than organisms that lack that  variant over evolutionary time, then the population will come to consist  solely of organisms possessing the reproductively efficacious variant  trait. In this way, populations of organisms will tend to acquire traits  that facilitate reproduction and lose traits that hinder reproduction.    We now know that what is passed on to offspring is a large DNA  molecule that is further partitioned into numerous sections called  genes. Because the structure of this DNA is intimately bound up with the  structure of the organism, variations in the DNA are strongly  associated with variations in the organism. Changes in DNA are referred  to as mutations, and result from environmental hazards such as  radiation, toxins, etc.   Reproduction is an enormously complex process. At any given  moment in the human body, there are thousands of process that, should  they fail to complete successfully, would result in death within  minutes. For this reason, any given random change in the body is likely  to hinder survival and reproduction, not facilitate it. There are far  more ways for a mechanism to fail than there are ways to improve it. How  many times has a change occurred to your car so that it got much higher  than the EPA estimated miles-per-gallon rather than much lower? Thus,  the vast majority of DNA mutations result in changes to the body (also  called the phenotype) that hinder reproduction. Occasionally, however, a  mutation occurs that results in a change to the phenotype that  facilitates reproduction. Because this mutation can be passed on to  offspring, and because this mutation tends to result in more offspring,  the mutation becomes more frequent in the population. Over time, this  process will result in organisms that have a sophisticated repertoire of  mechanisms that facilitate reproduction   We now have the answer to the question posed above: what  functions is the brain likely to perform? If brain tissue is organized  like all other tissue, it will perform precisely those functions that  facilitate reproduction. More accurately, because evolution by natural  selection is an historical process, and because the future cannot be  predicted, the brain and body will perform functions that facilitated  reproduction (note the past tense). Whether they currently do so will  depend on how closely the present resembles the past. If we can develop  an accurate picture of a species' reproductive ecology--the set of  physical transformations that had to occur over evolutionary time for  individuals to reproduce--we can infer those properties the organism is  likely to have in order to ensure that those transformations reliably  took place. Evolutionary time, the time it takes for reproductively  efficacious mutations to arise and spread in the population, is often  taken to be roughly 1000-10,000 generations; for humans, that equals  about 20,000-200,000 years.    Over the last 200,000 years, humans regularly encountered spiders  and snakes, creatures whose toxins would have significantly impeded the  reproduction of individuals unlucky enough to get injected with them.  Over the last 100 years, humans have regularly encountered automobiles,  encounters that also can seriously impede reproduction (e.g., by getting  run over). Because 200,000 years is long enough for humans to evolve  protective mechanisms, but 100 years isn't, we can predict that humans  may well possess an innate aversion to spiders and snakes, but not to  automobiles--even though far more people are currently killed by cars  than by spiders or snakes. Once we have firmly established that avoiding  spiders and snakes would have reliably facilitated the reproduction of  ancestral humans, we can then design experiments to determine whether  humans in fact possess an innate, cognitive ability to detect and avoid  these animals (more on how to do this below). A major lesson of  evolutionary psychology is that if you want to understand the brain,  look deeply at the environment of our ancestors as focused through the  lens of reproduction. If the presumptions of evolutionary psychology are  correct, the structure of our brains should closely reflect our  ancestral reproductive ecology. Thus, evolutionary psychology provides a  method for perceiving the functional organization of the brain by  studying the world--currently a far more tractable problem than  disentangling neural assemblages.Edward H. Hagen, Institute for Theoretical Biology, Berlin(fonte: http://www.anth.ucsb.edu/projects/human/evpsychfaq.html)