Man's Environment of Evolutionary Adaptedness

In the previous chapter it is emphasised that no system can be expected to operate effectively except in its environment of adaptedness. Because of this, when we come to consider with what instinctive behaviour—or, more properly, with what behavioural systems mediating instinctive behaviour—humans may be endowed, a first task is to consider the nature of the environment within which they are adapted to operate. This poses unusual problems.

Two main characteristics of man are his versatility and his capacity for innovation. Exercising these gifts he has in recent millennia extended the environments in which he is capable of living and breeding to include extremes of natural conditions. Not only this, but he has also, more or less deliberately, changed these conditions so as to create a series of entirely new man-made environments. These modifications to the environment have, of course, led to a spectacular increase in the world population of the species; and they have simultaneously made the biologist's task of defining man's environment of evolutionary adaptedness far more difficult.

At this point, it should be recalled that our problem is to understand man's instinctive behaviour. Thus, whilst full recognition must be given to man's remarkable versatility, his capacity for innovation, and his achievements in modifying his environment, none of these attributes is our immediate concern. Instead, we are concerned with the environmentally stable components of man's behavioural repertoire, and the relatively stable environment of adaptedness in which they were in all likelihood evolved. What, then, is the nature of that environment likely to be, or to have been?

For most species of animal the natural habitat not only is of limited variation but also changes only slowly. As a result each species is living today in an environment little different from the one in which its behavioural equipment was evolved and within which the equipment is adapted to operate. In