Pigeons learned discrimination rapidly and responded differentially to pictures seen for the first time. The essential feature of a natural discrimination--which is the ability to cope with natural ranges of variation--was approached and earlier experimental results were extended using other classes of stimuli. (Author/RK)

A model for the analysis of simple human conceptual behavior, based on the apparent similarities of human conceptual behavior and that of infrahuman subjects, is developed. A minimum definition of conceptual behavior is given: A single response, verbal or nonverbal, under the discriminative control of a group of stimuli whose parameters are…