Human recognition behavior is influenced by the phenomenon of shape constancy, which occurs when the shape of an object is correctly perceived regardless of the orientation of the object in space. The research reported here tests the validity of the shape-slant invariance hypothesis, a theoretical formulation of the phenomenon of shape constancy. Two experiments are reported. In one, individual differences were found to influence shape judgment performance, but stimulus shape did not. In the other, the shape and rotation of stimulus objects were found to influence judgments of shape and rotational orientation. The important implications of the results for recognition training in the army are discussed. Training for object recognition may be accomplished employing a limited number of views. (TL)