CHAPTER 10: HUMAN BEHAVIOR IN PERSPECTIVE
For a significant part of human evolution, people lived as foragers. The present human condition was shaped, in part, by evolutionary forces acting on hunting-gathering groups. The basic social unit of foragers is the band, which consists of adult males and females, subadults, juveniles, and infants. Bands are characterized by exclusive long-term male-female relationships. In human bands, women often leave the group of their birth and marry into a neighboring group. Continuing social relationships function to maintain social and economic relationships between bands. The degree of territoriality and intragroup fighting varies in different hunting-gathering societies. However, the concept of private ownership of land or warfare over territory is foreign to foragers.
Food sharing is an important feature of foraging societies where males and females perform different economic tasks and pool and share their food. Much of the vegetable food is difficult to find and process, yet such foods are often plentiful in harsh habitats. Young children are not capable of locating and processing such food and are dependent on adults for a long period of time after they are weaned. The last child might be born to human and chimpanzee females at around 45 years of age. This is followed by menopause, which is found in humans but is rare in chimpanzees. Postmenopausal women are especially efficient at locating and processing food. Thus in families where a postmenopausal female is present there is a higher survival rate of children, a shorter interval between successive births, and therefore a high inclusive fitness. This idea is known as the grandmother hypothesis.
Research into primate behavior reveals that many nonhuman primates, especially monkeys and apes, show protocultural behavior. While all organisms communicate, language has been regarded as a uniquely human form of communication that involved symbolic representations that are arbitrary and discrete. These characteristics, along with openness and displacement, differentiate language from the call systems of nonhuman primates and the communication systems of all other organisms. However, experimental work on apes has raised questions regarding the linguistic capabilities of nonhuman primates. Some researchers believe that apes have at least rudimentary linguistic abilities. Other researchers see the supposed linguistic behavior as nothing more than stimulus-response learning. Still others take a position somewhere in between these two conclusions.
Work done with monkeys suggests that intelligence is not an all-or-none characteristic and that primates are generally more intelligent than other animals. Some nonhuman primates display mental characteristics that were once thought to be distinctly human. These include the ability to categorize experiences and convey distinct and discrete meaning in their calls.
