An Evolutionary Model of Social Learning: The Effects of Spatial and Temporal Variation
Robert Boyd Emory University*
Peter J. Richerson University of California--Davis
From an evolutionary perspective, both individual and social learning can be viewed as forms of phenotypic plasticity. Both modes of learning are developmental processes that cause organisms to acquire different behaviors in different environments. Phenotypic plasticity may be adaptive in temporally or spatially varying environments if the use of environmental cues enables organisms to acquire behavior that is adaptive in each local habitat. For example, by sampling novel foods and learning to avoid noxious food types, a cosmopolitan species like the rat can acquire an appropriate diet in a wide range of environments. Mechanisms of phenotypic plasticity may also have fitness costs. By sampling novel foods, the rat incurs risks that could be avoided by an animal with rigid genetically specified food preferences.
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 learn-____________________