Learning to categorize perceptually similar stimuli can result in people becoming more sensitive to differences along perceptual dimensions that are relevant to category membership and/or less sensitive to equivalent differences along irrelevant perceptual dimensions. These effects of acquired distinctiveness and acquired equivalence may be caused…

Two experiments explored the nature of perceptual development in 5- and 10-year olds and adults. The primary finding was that preassessed salience significantly influenced 5-year olds' ability to discriminate two objects, while salience did not affect 10-year olds' or adults' response times. Results showed that salience effects in perceptual…

Children with mental retardation are particularly prone to failure on relational tasks such as oddity and match-to-sample, suggesting a differential sensitivity to relational information. This paper reports on several studies in which characteristics of stimulus arrays were enhanced. Results demonstrated the theoretical and practical significance…

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…