Human evolution and the capacity to categorize

Abstract

We have studied—with the help of a mathematical model of cultural transmission—evolutionary effects which may derive from the appearance of a conceptual capacity to categorize behavior (approving or disapproving of it) in one of our hominid ancestors. We consider acquisition of behavior through individual learning and rudimentary cultural transmission. The ability to categorize behavior produces an increase in the efficiency and the flexibility of the cultural transmission process. Moreover, the capacity to categorize allows the acquisition, through cultural transmission, of information about behavior, similar to that provided by individual learning (i.e., an individual's interaction with the environment, in contrast to the receipt of lessons learned by others) but avoids unnecessary costs by not having to resort to experience. An analysis of the model reveals that the advantage in terms of fitness in individuals capable of categorizing compared to individuals without this ability increases the greater the difference in the intensity of cultural transmission between them and declines the greater the probability that behavior with adaptive importance can be developed without the need of culture, that is, solely through individual learning. Finally, we suggest that intelligence has developed, within this framework of the cultural transmission, as a new system, outside the limbic-hypothalamic system, capable of generating values and showing preferences between different kinds of behavior.