Studies in concept formation. IV. A comparison of white rats and raccoons with respect to their visual discrimination of certain geometrical figures.

Abstract

Four raccoons were trained on a 5 unit discrimination box. The animals successfully learned to discriminate differences of a.) brightness (light and dark alleys), b.) between an equilateral triangle and a circle of 27.7 sq. cm., c.) the same stimuli but of 55.4 sq. cm., and d.) between a circle and an equilateral triangle rotated through different degrees. With decreases in the size of the stimuli to be discriminated there were decreases in the accuracy of response, indicating that some of the smaller figures may have been below the raccoons'' "configurational difference limen.".