Methodological resources for the experimental study of innate behavior as related to environmental factors

The principal methods available for studying innate behavior in animals are: (1) The method of uniform heredity and varied environment. Here the unit of primary importance is the individual. (2) The method of uniform habitat and varied heredity. Here the habitat is standardized. (3) The method of genetic analysis. This is a relatively direct method of studying the heredity of behavioral traits in animals by noting effects of crossing strains. (4) The method of cytological analysis in its simplest form consists of counting the chromosomes of various populations under consideration. The truest picture of innate and hereditary influences is obtained by combined use of the 4 methods on the same species.