Abstract : An investigatio of stimulus situations, characteristic of the physical and social environment, that might account for the unaccounted variance in individual and group behavior which cannot be predicted by personality traits and aptitudes was made. Current empirical research involves the collection of data from undergraduate students to sample both their individual characteristics and the environmental stimuli to which they are exposed. Future plans involve the dimensionalization of social and physical environmental events into composite clusters that will help predict behavioral criteria, and contribute to the endeavor of constructing a taxonomy of situational variables to give a more complete account of behavioral variance. (Author)