The ways in which individual learning and social learning allow organisms to adapt to different environments are, however, quite different. Behavioral variants acquired by individual learning are not transmitted from one generation to the next. This means that each individual's behavior develops independently based on the interaction of genetically inherited learning mechanisms and the local environment. Generic variation underlying learning mechanisms may evolve, but the behavioral variants acquired by learning do not. Individual learning is adaptive if it bestows some advantage on the individual. In contrast, behaviors acquired by the imitative and observational forms of social learning are transmitted from one individual to another and thus from one generation to the next. From an evolutionary biologist's perspective social learning is interesting because it mixes aspects of a system of inheritance with aspects of ordinary phenotypic flexibility, creating a system for the inheritance of acquired variation. To understand the conditions under which social learning is adaptive we must understand how individual learning and social learning interact to determine the evolutionary dynamics of the behavioral variants themselves as well as the genes that underlie learning processes.
The evolutionary properties of the inheritance of acquired variation have received relatively little theoretical attention. This inattention may be due to the fact that evolutionary biologists have supposed that the inheritance of acquired variation is rare in nature, essentially restricted to human culture and a few unusual animal systems, such as the songs of some birds. Those biologists who have imagined that social learning is common in animals besides humans have not always taken proper account of the difficulty of demonstrating true imitation in the face of several processes that can mimic its effects. With a few exceptions recent theoretical work on cultural transmission has concentrated on explaining human culture rather than on the more general properties of social learning (Blonski, 1999).
Under what circumstances should natural selection favor a growth of reliance on social learning at the expense of individual learning The answer to this question is important because it seems likely that social learning originally evolved in species with extensive individual learning abilities. Our focus on the adaptive value of social learning does not imply that selection is the only important evolutionary process, or that all behavior is adaptive. We do believe, however, that understanding the conditions under which social learning is adaptive is an important first step in understanding its evolution and the conditions under which one would expect to find social learning in nature.
At first glance, it may seem that social learning will always be the superior form of phenotypic plasticity. Acquiring adaptive behavior by conditioning and other forms of individual learning is often an inefficient process. Learning trials divert time and energy from other fitness-enhancing activities, they may entail serious risks, and there may be substantial chance of not