0.10 Biology and personality  (Page 7/22)

The fundamental concept underlying sociobiology is that of inclusive fitness . Inclusive fitness refers to the advantages of behaviors that increase the likelihood of an individual’s genetic survival through the survival of genetically related kin (Barash, 1977; Wilson, 1975). Therefore, in looking at the evolution of human social behavior, we must not consider only the ways in which behaviors contribute to individual survival (which is a traditional Darwinian perspective on survival of the fittest), but rather on how behaviors contribute to the survival of our children, family, and perhaps even our community.

Sociobiologists have looked at several major topics regarding the evolution of human behavior, but we will only take a brief look at three behaviors: mate selection, parenting, and religion. In Chapter 2 we discussed male/female differences as a matter of fact. This has become commonly accepted in the popular media, and evidence suggests that men and women are inclined to essentialize their differences (Prentice&Miller, 2006). In contrast, Janet Shibley Hyde has provided compelling evidence that men and women are actually much more alike than they are different (Hyde, 1996, 2005; also see Spelke, 2005; Stewart&McDermott, 2004). So which is it? When it comes to mate selection, sociobiology suggests that men and women should be different, because the roles they will need to play in eventual child rearing require them to be different. It is a biological fact that men need to contribute very little to the birth of a child, whereas women become pregnant for nine months and, from an evolutionary perspective, must then breast-feed the child for one or two years. Thus, a man can improve his inclusive fitness by seeking multiple relationships with women in their prime child-bearing years and exhibiting physical characteristics indicative of good reproductive health. Unfortunately, other men are looking for the same women, so competition can become fierce. Women, on the other hand, should be inclined to seek men who have already won those competitions, demonstrating that they can provide and protect resources for their offspring, usually by commanding a territory or a privileged place in society (Barash, 1977; Wilson, 1975, 1978). So it is not uncommon for women to be inclined to marry older men, particularly men who are above them on the socioeconomic scale (Barash, 1977). Women would also be inclined to select men who make some commitment in terms of child rearing (Barash, 1979). So, men who were inclined to make only the minimum commitment necessary to the sexual act did not improve their inclusive fitness, since they were not selected by discriminating females.

When parenting is discussed in introductory psychology courses, the most common topic is parenting styles and their influence on personality development. In sociobiology, however, the most relevant issues are the survival of the offspring and how taxing it is on the parents to help their offspring survive. We are just beginning to understand some aspects of the biological basis for attachment from the offspring’s perspective (Hofer, 2006), but understanding the attachment of the parent to the offspring remains elusive. Obviously, raising a child requires a considerable amount of effort on the parent’s part, but typically more on the part of the mother. Thus, close social bonding is important, and this may form the basis of love as an added emotional component to sex, as well as the growing love that parents feel for their children (Barash, 1977; Wilson, 1978). Older women are particularly more sensitive to the needs of first-born children, since the child may well represent the only opportunity for the mother to reproduce. Nature is full of well-known examples of female animals vigorously defending their young, even if their own life is endangered (Barash, 1977, 1979). Of peculiar interest is the behavior of grandparents, since a parent is really only successful in reproducing if they eventually become grandparents. Barash (1977) discusses two interesting situations. When a child is born, it is most likely that the mother’s parents come to help. But if a young couple chooses to live with parents, it is most likely the father’s parents. These may simply seem to be cultural artifacts, but they have a basis in biological fitness. Only a mother can be sure that she has made a genetic contribution to a child (at least in the past, when our behaviors were evolving). So, when a woman has a baby, only her parents are sure that they have become grandparents. The man’s parents serve their own interests best if they can watch over the woman, to make sure that she does not stray from her relationship with their son (Barash, 1977). All of this may sound cold and calculating, but it is logical nonetheless, and if we believe in an unconscious mind, then people don’t need to be aware of exactly what they are doing.