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…

A skill essential for successful inclusion in general education settings is the ability to learn by observing others. Research, however, has documented children with autism display significant deficits in the fundamental skills necessary for observational learning. This article outlines the skills essential for observational learning from an…

In both healthy participants and various patient populations, performance on attentional set-shifting tasks has been found to be affected by learned irrelevance and/or perseveration. The present study examined whether or not these processes also play a role during the initial discrimination learning phase of those tasks. To this end, participants…

We compared the ability of auditory, visual, and audiovisual (bimodal) exogenous cues to capture visuo-spatial attention under conditions of no load versus high perceptual load. Participants had to discriminate the elevation (up vs. down) of visual targets preceded by either unimodal or bimodal cues under conditions of high perceptual load (in…

Research was conducted on two selective attention systems in learning situations. The theoretical and experimental approaches are presented in a set of six papers. One paper considered directions in attention theory and five papers report experiments with pigeon and children subjects. The two attention systems are (1) coding response, which…

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.

Five experiments examined the relations between timing and attention using a choice time production task in which the latency of a spatial choice response is matched to a target interval (3 or 5 s). Experiments 1 and 2 indicated that spatial stimulus-response incompatibility increased nonscalar timing variability without affecting timing accuracy…

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…