Generalization of learning can arise from 2 distinct sources: failure to discriminate a novel test stimulus from the trained stimulus and active extrapolation from the trained stimulus to the test stimulus despite them being discriminable. We investigated these 2 processes in a predictive learning task by testing stimulus discriminability…

Eight experiments using as Ss either retarded children, normal children, or normal adults studied the relations of retardation and normal development to the perceptual process of identification. Two experiments were reported on the identification of stimuli varying in either one, two, or three dimensions. Retardates did not perform as well as…