Sociobiology

Sociobiology is the study of animal and human behavior in terms of evolution. Its tenet is that the theory of evolution applies not only to anatomy and physiology but also to behavior. Sociobiology maintains that individuals chosen by natural selection are those whose genes encourage behaviors that contribute to reproductive success. Some topics studied by sociobiologists are aggressiveness, gender differences, dominance hierarchies, mate selection, and territoriality.

In the 1960s, W. D. Hamilton applied these concepts to understand altruism among animals. In 1975, the zoologist Edward O. Wilson published his book "Sociobiology: The New Synthesis" that established the field. A great controversy developed as a result of Wilson's claims that human behavior was subject to natural selection. It must be noted, however, that biologists have not deduced that human behavior is only the result of instinct, nor they have drawn any conclusion about the morality of adaptive behavior.

Several human activities have been analyzed in search of their adaptive significance. An example is parenting, an activity that involves many efforts. It can be guessed that an individual would be willing to make such investment only for the sake of offspring that would propagate his own genes. This would lead to predict that males would react with anger to the idea of an adultery, which is indeed the case in the majority of cultures.

Preferences about food have also been analyzed from an evolutionary point of view. It is well known that people usually prefer sweet-tasting foods rather than bitter ones. This is an instinctive behavior controlled by neurons of the brain. One may ask what could be the adaptive significance of this preference, that is, how it could have increased the chances of producing more offspring back in the prehistoric ages. A possible answer is that sweet foods contain calories that were valuable for the prehistoric man. Bitter-tasting foods, on the contrary, are generally associated with toxic substances that would threat his health.

In spite of the attraction of this kind of reasoning, it must be remembered that there is still much to be learned about how genes govern the development of the nervous system and, consequently, influence behavior. Few studies still exist that show how nerves and hormones control a behavior pattern. A more improved knowledge is needed of the relationships that exist between genes, physiology, and behavior. If it is undoubtedly that natural selection may have contributed to shape human behavior, much research has still to be done.

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