Sociobiology2

Darwin suggested partial inheritance of behavior in The Descent of Man, although before the discovery of genes he did not suggest how it could happen. Spencer applied evolutionary theory to society, the doctrine known as “Social Darwinism.” Lorenz (Chapter 4) discovered imprinting, showing that some behaviors are wired into the brain in some species.

Biologists have a hard time understanding altruism (helping another at the expense of one's own fitness to reproduce) as it seems inconsistent with their fundamental assumption that individuals seek to pass on their own genes. If the extent an individual passes on its own genes is the measure of biological success, then taking risks to help unrelated individuals makes no sense. Yet altruistic and cooperative behavior undeniably does exist!

Explanations consistent with genetic altruism first emerged from studying social insects—bees, ants and the like—most of which are hymenoptera. In hymenoptera, siblings share three-quarters rather than half of their genes. Therefore, individuals pass on more of their own genes by caring for siblings rather than raising their own offspring. This led to the hypothesis that haplodiploid insects became social due to genetics.

Here and there, genetic explanations of cooperative behavior are emerging in other species. Packer and Heinsohn (1995) discovered that lionesses tolerate laggards in defense if they make other contributions to pride survival such as better skills at hunting or babysitting.

All this set the stage for Edward Wilson, entomologist by profession, poly-math by inclination. Assuming that animals evolve behaviorally as well as physically to maximize transmission of their own genes and thus biological success, Wilson (1975) proposed a new science he called sociobiology. As one element, he proposed eight types of agonistic behavior rooted in genetics³ that combine in various ways in different species and forms of social organization.

Anti-predatory behavior is primarily defensive. Most animals prefer fleeing to fighting, but most have some means of defense. A zebra’s kicks can break a pursuing lion’s jaw. A lion so injured will starve, so it attacks carefully, providing that slight margin that allows zebras to escape most but not every time.

Dominance behaviors exist only in species that live in hierarchical societies and determine each individual’s place in it. With rare exceptions, humans live in hierarchical societies. However, the basis varies widely both within and between cultures.

Moralistic aggression consists of punishment to enforce behavioral norms and group standards.

Parental discipline is mild verbal or physical aggression to keep offspring close at hand, urge them into motion, break up fighting, and enforce limits.

Predation is seen as aggression by sociobiologists such as Wilson, who sees it as indistinguishable from murder and cannibalism but not as aggression by ethologists such as Lorenz or psychiatrists such as Fromm.

Sexual aggression occurs when males threaten or actually attack females for the sole purpose of mating. In some species, especially among some spiders, the female is the aggressor, eating males immediately after mating. Hamadryas baboons build and maintain their harems by force. Gelada baboons do not. In one experiment, Gelada females placed with Hamadryas males escaped at the first opportunity, but Hamadryas females placed with Geladas had the good sense to avoid returning to the Hamadryas troops.

Territorial aggression involves staking out and defending a home territory. There are three main patterns. Least common is the mating station, a territory that each male stakes out to attract females. Once a claim is established, the owner almost always bests any challenger, often by symbolic combat that minimizes the likelihood of injury. Outside the territory, in the foraging area, males do not fight one another. The pattern is possible only in species in which females rear the young without assistance from the male, one reason that it is found only in about 100 of the world’s million or so animal species including at least one insect, the cicada killer, a species of wasp.

The second pattern is the pair territory. Although often first staked out by the male, it becomes the territory of a breeding pair and assures proper care of the offspring. It is common in birds, exemplars being penguins and gulls. Pairs occupy relatively small nesting territories, which they most often defend by displays at their borders. Humans sometimes follow this pattern in dealing with their neighbors. As Robert Frost said, “Good fences make good neighbors.”

The third pattern is the “nation,” a territory held by a group as an exclusive possession through joint defense (Carpenter 1934). Carpenter and others demonstrated that baboon, chimpanzee, gorilla, lemur, and rhesus family groups remain intact even when females are not in season. These findings suggest that joint defense of territory rather than food supplies or sex holds the family group together. Humans also exhibit this pattern.

Weaning in some animals takes the form of gentle attacks to prevent the young nursing and force them to turn to adult food. The longer a young animal can nurse, the better off it will be, but the longer the mother must nurse the more her fitness is lowered. Erikson (Chapter 4) specifies weaning as one of eight life crises that can lead to personality disorders.