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…

A linked perceptual class consists of two distinct perceptual classes, A' and B', the members of which have become related to each other. For example, a linked perceptual class might be composed of many pictures of a woman (one perceptual class) and the sounds of that woman's voice (the other perceptual class). In this case, any sound of the…

Thurstone's landmark papers on psychophysics, published in the twenties, are discussed in this presidential address to the Psychometric Society. The development of psychophysics from Thurstone to the present is presented in some detail. (JKS)

This report summarizes research concerning stimulus analyzing mechanisms, giving the main experimental findings and theoretical developments. Most of the data and the experimental findings are to be found in the 89 publications listed in the bibliography. The research is discussed under five main headings: (1) shape recognition, (2) selective…

Research supported by a U.S. Public Health Service fellowship grant and by grant No. 01368-04 from the National Institute of Child Health and Human Development.

The purpose of the two experiments was to assess the effects of two levels of stimulus redundancy and three levels of irrelevant visual stimulation on performance in a successive discrimination task and a reproduction task. The results indicate that increases in redundancy facilitated performance in the reproduction task but had no appreciable…

A surprising validation of expectation experienced during a recognition test induces the perception of discrepancy and a feeling of familiarity. The authors investigated whether that perception also affects memory performance when it is experienced in the original encounter with a stimulus. Target words were presented in a study phase, half in…

Paper is based on a dissertation submitted to Brown University in partial fulfillment of the requirements for the Ph.D. degree in Psychology, June, 1966.