Abstract
The purpose of this article was to address issues on what the role of species comparison is for the studies of animal psychology. Whereas some people think that the comparison has a critical role in their approaches, others do not. We classify these two groups of people as evolutionists and generalists, respectively. In the evolutionary approach, different species are compared to examine correlations between specific selective pressures (such as caching food) and cognitive abilities (such as spatial learning) in animals. In contrast, different species of animals are compared to examine universal principles of learning in the generalist approach. Although the generalists' ideas of the “universal” principles of learning provide parsimonious explanations of animals' behavior, they tend to underestimate influences of selective pressures on learning and cognition. We therefore propose a new framework for the study of animal learning and cognition; it is based on the evolutionary approach and examines ultimate causes of diversities of learning and cognition but includes ideas of generalists' approaches to explain proximate causes.
