Describes the establishment of a psychological space for any set of stimuli by determining metric distances between the stimuli with the probability that a response learned for a stimulus will generalize to the other. (Author/TW)

Describes recent research findings in the area of neurobiology and its relationship to learning and memory. The article provides definitions of associative and nonassociative learning, identifies essential memory trace circuits of the mammalian brain, and discusses some neural mechanisms of learning. (TW)