Children and adults were trained and tested on formation of novel simple discriminations and conditional stimulus relations. Subjects who formed these sets were trained and tested on formation of stimulus equivalence classes. A modest majority of children matched directly paired stimuli; a few matched indirectly paired stimuli. All normal adults…

Infants in four age groups--three, six, nine and twelve months--were exposed to an experimental procedure designed to assess the extent to which such subjects were capable of discriminating between different orientations of the same form, and the extent to which they were capable of recognizing the identity between different orientations of the…