SOCIOBIOLOGY The Adaptationist Program

Transcription

1 1 Lecture 12 SOCIOBIOLOGY DEFINITION: The comparative study of behavior involves the analysis of similarities and differences in the causes and consequences of behavior of animals, both within and between major taxonomic divisions. Such analyses require comparisons among a variety of species whose morphology, behavior, and ecology are sufficiently diverse to reflect the range of solutions which have evolved to meet the adaptive requirements of the environment. But no definition is without controversy. Origins of Sociobiology: A commonly accepted beginning for sociobiology is Hamilton s (1964 Hamilton, William D. (1964) The genetical evolution of social behavior, I and II. J. Theoretical Biol. 7:1-52.) idea: The social behavior of a species evolves in such a way that in each distinct behavior-evoking situation the individual will seem to value his neighbor s fitness against his own according to the coefficients of relationship appropriate to that situation (p. 19). And the ideas that followed of inclusive fitness, including direct and indirect fitness. (Crawford, Charles (1991) Psychology. In: The Sociobiological Imagination SUNY Press, Albany. pp ). The hard core of narrow sociobiology includes the following laws or problem solving strategies, the basics of evolutionary theory: Descent with modification (Darwin), Inclusive fitness (Hamilton), Game theory (Maynard Smith), Optimization theory (Trivers). The Adaptationist Program The adaptationist program comes in two forms. In the forward form, the scientist postulates an environmental problem, then searches for the solution to the problem in the organism s phenotype. In the backward form, the scientist starts with a known phenotypic solution, then searches for the environmental problem that could have produced it (Lewontin, 1979). As an example of the backward form of the adaptationist program, we know that birds have wings, so we can reason backward to try to uncover the environmental problem to which wings are a solution. Heat regulation is such a problem. Early wings allowed birds to capture or release heat, thus allowing them to live in either cold or hot environments. As another example of the backward form of the adaptationist program, we know that human infants smile, cry, follow, approach, cling, etc. Each of these behaviors has the effect of increasing proximity with the caregiver, so we can reason backward to try to uncover the environmental problem to which proximity to the caregiver is a solution. Protection of the infant from predators is such a problem. In the ancestral environment in which the species emerged, infants who did not maintain proximity with their caregivers did not survive to reproduce. Problems in the Adaptationist Program Sociobiologists have failed to recognize or adequately deal with several major problems inherent in the adaptationist program. The first set of problems is problems with description. Descriptions are inherently theory -laden. Concepts such as entrepreneurship, slavery, dominance, aggression, tribalism, and territoriality, referred to routinely by sociobiologists, may have no independent existence whatsoever in the world of organisms (Lewontin, 1979). Problems with description come in four varieties: arbitrary agglomeration, reification, anthropomorphism, and reductionism. First, arbitrary agglomeration is describing something, e.g., the hand, as a single unit of analysis, when in fact natural selection may operate rather on its constituent parts, e.g., the thumb. Second, reification is assuming that mental constructs, such as property or terrioriality, are the objects of natural selection, when in fact, specific mental constructs are not real objects (Lewontin, 1979, p. 8). The status of more tribal than differs qualitatively from the status of heavier than (Lewontin, 1979). Third, anthropomorphism occurs when concepts that originally referred to human social relationships, e.g., rape, are applied to non-human animals. When thus applied, the concepts necessarily lose their human historical and cultural meaning. However, sociobiologists often, upon finding that a condition like rape occurs in non-human animals like mallards, proceed to claim that an evolutionary basis or genetic predisposition has been found for the human condition referred to by the same word (e.g., Barash, 1979). To do this is to conflate the original meaning of the word rape with a derived, metaphorical meaning (Lewontin, 1979). There appears to be no common mechanism or common function between rape in mallards and in men. Therefore, the entire case seems to rest upon the question-begging terminology (Kitcher, 1987). Fourth, reductionism is the assumption that properties of collective social organizations arise from the properties of their constituent individuals (which themselves arise from the individuals genes). For example, war (aggression of one society against another) is supposed to arise from individual aggressive feelings. In an analysis of the behavior of tribes and nations, Wilson (1978) concludes that humans are strongly predisposed to respond with unreasoning hatred to external threats and to

2 2 escalate their hostility sufficiently to overwhelm the source of the threat by a wide margin of safety (p. 119). Reductionism makes it impossible for sociobiology to deal with uniquely social properties. For example, social revolution occurs at a rate too rapid to be explained by genetic variation alone (Lewontin, 1979). Inclusive Fitness The idea of inclusive fitness, or kin selection, is an important component of contemporary evolutionary theory. Haldane (1955) understood the process, as indicated by his remark that he would lay down his life for two brothers or eight cousins. However, the idea was mainly popularized by Hamilton (1964a, 1964b). The main theoretical yield of the concept of inclusive fitness is that it explains (or perhaps explains away) altruism. Genes are selfish, and a person is merely a gene s survival machine (Dawkins, 1989). However, a gene s fondest wish (to anthropomorphize a bit) is to be passed into the next generation. This can occur if the person carrying the gene survives to reproduce--but it can also occur if the person's relatives (who carry many of the same genes) survive to reproduce. Thus, a lapwing will fake injury to distract a hawk from its young, thereby acting altruistically toward its offspring (Maynard Smith, 1995). Sometimes the altruistic act benefits non-relatives. For example, members of many species will take care of youngsters, even if the youngsters are not their own. This may be because the evolved mechanism is not sensitive enough to make fine discriminations, opening the altruist up to exploitation. People who take care of pets, for example, are having their care-taking mechanism exploited (Maynard Smith, 1995). Wilson s Ladder The following is the basic argument of pop sociobiologists, called Wilson s ladder (Kitcher, 1987). 1.IF a behavior maximizes fitness, THEN the behavior will exist in virtually all members of a group. 2.IF a behavior exists in virtually all members of a group, THEN the behavior came about by natural selection. 3.IF a behavior came about by natural selection, THEN there were once individual differences in the group s genetic makeup. 4.IF there were once individual differences in the group s genetic makeup, THEN there are differences in the genetic makeup of the present group from its prehistoric ancestors. 5.IF there are differences in the genetic makeup of the present group from its prehistoric ancestors, THEN the genetically adaptive behavior will be difficult to modify by social engineering THEREFORE, IF a behavior maximizes fitness, THEN the genetically adaptive behavior will be difficult to modify by social engineering. Problems with Wilson s Ladder--Level 1 Level 1: IF a behavior maximizes fitness, THEN the behavior will exist in virtually all members of a group. Pop sociobiology offers explanations of ecstacy at football games, forebearance in combat, and dominance displays in men, all in terms of maximizing fitness. However, the application of evolutionary principles may be overly hasty and unrigorous, not only when applied to humans, but even when applied to non-human animals. For example, one author (Orians, 1969) predicts that, in order to maximize fitness, virtually all swans, geese, and ducks should be polygynous. They are not. Therefore, the author introduces a new variable, high-latitude, and says that monogamy occurs only in high-latitude species. This conventionalist strategem comprises a theoretically degenerating problemshift (Lakatos, 1970). Genetic Determinism The first variety of genetic determinism is the rather unsophisticated doctrine of genetic fixity, which holds that the genes of parents inevitably determine the characteristics of their children. (Dennett [1996] dramatizes this simple form of determinism under the label sphexishness.) Genes, of course, do influence human development. The differences between humans and chimps are almost entirely genetic. However, even the completion of the human genome project will not enable scientists to predict how a child will develop. Indeed, even a complete knowledge of a child s genes and environment would not allow the complete specification of the organism: chance also plays a significant role in development. This can be seen, for example, in the number of bristles under a fruitfly s wing: this number varies from the left wing to the right, despite the fact that the fruitfly has the same genes and environment on both sides of its body (Lewontin, 1991). Such differences may not be due to pure chance, however, but rather to non-linear dynamic (chaotic) deterministic processes (Molenaar, Boomsma, & Dolan, 1993). Such processes have been shown possible using computer simulations, but whether they operate in real organisms remains an empirical question. The second variety of genetic determinism is the slightly more sophisticated doctrine of innate capacity, according to which people are like buckets waiting to be filled (Lewontin, 1991). In an impoverished environment, all people will end up with similar characteristics (wealth, knowledge, etc.); but in an enriched environment, those who naturally have big buckets will

3 3 end up with more than those with small buckets could possibly hold. For example, people who are malnurished will show smaller individual differences in height than those who are well nourished. The third and most sophisticated variety of genetic determinism is the doctrine of statistical variation, according to which all individual differences can be parsed into either genetic determinants or environmental determinants in some proportion (Lewontin, 1991). For example, it might be said that 80 percent of the variance in children s performance on I.Q. tests is due to genetic influences, and only 20 percent is due to environment. The practical implication seems to be that even a radical change in environment will have only a modest effect on performance. However, this is not the case, as can be seen from the following examples. An ordinary student in primary school today can add a column of numbers much faster than even the most intelligent ancient Roman mathematician, who had to deal with cumbersome X s, V s, and I s. The same student, using an inexpensive calculator, can multiply two five-digit numbers faster than even the most intelligent mathematician a century ago (Lewontin, 1991). Heritability does not imply immutability. This can be seen from the example of PKU (phenylketonuria), a form of retardation. PKU can be cured by keeping people from eating phenylalanine. One hundred years ago the proportion of genetic variation in acquiring PKU was 100 percent; now individual differences in acquiring PKU are almost completely non-genetic (Plomin, DeFries, & McClern, 1990). Kitcher s Ideas A. Sociobiology tries to explain the factors that affect human behavior 1. Broad sociobiology deals with humans as well as animals, and helps in answering certain questions of behavioral tendencies in general. 2. Narrow sociobiology uses the evolutionary theory as its backbone to explain specific behavior in animals and humans. 3. Pop sociobiology also takes some ideas from the evolutionary theory, but then uses these doctrines to explain the concept of human nature. B. Sociobiology also makes a mistake when it tries to use anthropomorphism and reductionism to explain its ideas. C. Sociobiology is misleading because it relies on the evolutionary process to explain for certain phenotypic qualities. D. Richard Alexander s inclusive fitness idea does not have any proof to back it up. In fact it is a very misleading idea to believe in that there is general inclusive fitness feeling among all humans. E. Lumsden and Wilson s idea of a genetical-cultural evolution is incorrect due to its strong argument on how the genetic aspect of the evolution is directly responsible for the cultural aspect. This is because while genetics may truly affect certain individual s behavior, it does not mean an entire culture can be shaped due to presence of certain genes in its population. Ideas of R. C.Lewontin In his article Sociobiology as an adaptationist program, Lewontin attempts to show how sociobiology takes the scientific theory of evolution and mutates it into a psuedoscience, where it will remain until something is done about its problems. I. Sociobiological Adaptationist Program - The sociobiological approach that believes that behavioral traits are direct results of the best adaptations of genes to solve problems. A. Forward Form - A problem in an organisms life is pinpointed and then behavioral traits or adaptations are studied for the solution. B. Backward Form - A behavioral trait is pinpointed and assumed to be the solution to a problem. It is then analyzed until the problem it solved becomes apparent. II. Errors in the Adaptationist Program A. Error of Description 1. Arbitrary agglomeration - There is no way to partition the parts of behavior into separate catagories and talk about the evolution of each part since there is no clear division and there is no evolution of behavior as a whole. 2. Reification - Sociobiologists convieniently forget that evolution occurs only in real objects and cannot occur in the metaphysical world of thoughts. Yet, they constantly try to apply evolution to mental constructs (Lewontin, 1979, p 7) such as property and terretoriality. 3. Conflation - Frequently, sociobiologists apply terms from human social context to metaphorical behaviors in the animal world. In the process, the terms become associated with the metaphorical animal behavior and when they are reapplied to explain human behavior in society, the terms no longer have the original meaning. 4. Confusion of levels - By its very name sociobiology is meant to deal with the behavior of society, but it often deals with individual behavior. It falsely assumes that societal behavior is simply a collection of individual human behavior. B. Error of Heritablity 1. Genetic Varience - In order to prove genetic heritability and therefore sociobiology true, there must be a knowledge of the comparative numbers of genetic varience for different characteristics. Since this is impossible to find out, sociobiology will never truly reach scientific status. Yet, sociobiologists tend to ignore this fact. 2. Genetic vs. Environmental - In order to prove genetic heritability true, one must be able to separate the environmental aspect from the truly genetic aspect. Since even physiological traits such as hair color depend on environment to some degree (people from India have black

4 4 hair), imagine the degree of environment dependability behavior must have. C. Error in Adaptive Stories - Sociobiologists create stories to explain why certain features of creatures are the fittest. 1. Progressive Ad Hoc Optimization - A particular problem of an organism is analyzed and the trait that would solve that problem is inferred. The organism is then studied for that trait. If the trait has not arisen in the organism, then a second problem is found that another trait can be a solution to both of them. Therefore, this method is not falsifiable and so, cannot be scientific. 2. Imaginative Reconstruction - A species trait, past or present, is isolated and a reason or problem is deduced for a trait to be favored in the process of natural selection. Although this problem could be right, it could also be completely wrong even though there was no way of proving it so. This makes this method also unfalsifiable and therefore, unscientific. III. Alternatives to adaptation A. Adaptation does not always follow natural selection. B. There are multiple paths of evolution and the path is selected by chance. C. The Limited gene pool assures the fact that sometimes species with a less fit gene will survive. D. Change in character comes from the result of general gene action not a specific gene selection. E. Allometric growth occurs even if it is not generally the fittest trait for a species since it is not extremely harmful. F. Change from developemental random noise is as great as from the environment and genetics. References Barash, D. (1979). The whisperings within. New York: Penguin. Daly, M., & Wilson, M. I. (1996). Violence against step-children. Current Directions in Psychological Science, 5, Dennett, D. C. (1996). Elbow room: The varieties of free will worth wanting. Cambridge, MA: MIT Press. Hofstadter, D. R. (1982). Can creativity be mechanized? Scientific American, 247, Konner, M. (1985, October 6). One gene at a time. The New York Times Book Review, 48. Lakatos, I. (1970). Falsification and the methodology of scientific research programmes. In I. Lakatos & A. Musgrave (Eds.), Criticism and the growth of knowledge (pp ). New York: Cambridge University Press. Lewontin, R. C. (1979). Sociobiology as an adaptationist program. Behavioral Science, 24, Lewontin, R. C. (1991). Biology as ideology: The doctrine of DNA. New York: Harper Collins. Molenaar, P, C. M., Boomsma, D. I., & Dolan, C. V. (1993). A third source of developmental differences. Behavior Genetics, 23, Orians, G. (1969). On the evolution of mating systems in birds and mammals. In T. Clutton-Brock & P. Harvey (Eds.), Readings in sociobiology. Freeman. Plomin, R., DeFries, J. C., & McClern, G. E. (1990). Behavioral genetics: A primer (2nd ed.). New York: Freeman. Woodridge, D. (1963). The machinary of the brain. New York: McGraw Hill. Kitcher, P. (1987). Préis of Vaulting ambition: Sociobiology and the quest for human nature. Behavioral and Brain Sciences, 10, Wilson, E. O. (1975). Sociobiology: The new synthesis. Cambridge, MA: Harvard University Press. Wilson, E. O. (1978). On human nature. Cambridge, MA: Harvard University Press. Wilson, M. I., & Daly, M. (1996). Male sexual proprietariness and violence against wives. Current Directions in Psychological Science, 5,

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