In many non-human species, learning retention decreases temporarily following training. This has led to the suggestion that these lapses reflect a fundamental component of memory formation. If so, transient memory lapses should also be prevalent in humans, and should occur for all types of learning. In line with these predictions, we report two…

Are there some differences so small that we cannot detect them? Are some quantities so similar (e.g., the number of spots on two speckled hens) that they simply look the same to us? Although modern psychophysical theories such as Signal Detection Theory would predict that, with enough trials, even minute differences would be perceptible at an…

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…

Monkeys will selectively and adaptively learn to avoid the most difficult trials of a perceptual discrimination learning task. Couchman, Coutinho, Beran, and Smith (2010) have recently demonstrated that this pattern of responding does not depend on animals receiving trial-by-trial feedback for their responses; it also obtains if experience of the…

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…

Time perception is important for many aspects of human behavior, and a large literature documents that adults represent intervals and that their ability to discriminate temporal intervals is ratio dependent. Here we replicate a recent study by vanMarle and Wynn (2006 ) that used the visual habituation paradigm and demonstrated that temporal…

Seven rhesus monkeys reared on diets high in phenylalanine to induce phenylketonuria (PKU--a metabolic disorder associated with mental retardation if untreated) were compared with normal, pair-fed, and younger controls; frontal brain-lesioned monkeys; and those raised on high-tryptophan diets in three object discrimination tasks. (Author)

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)

Subjects were 359 children divided by grade (3 and 6), culture (U.S. and Indian), and sex. Hypothesis was that developmental, cross-cultural, and sex differences would be found in the perception of situational causality. All cross-cultural and developmental differences were found to be significant for U.S. children but not for Indian children. (RJ)

Results indicated that in both adults and infants combined cues facilitate discrimination of the phonemic contrast regardless of whether the cues cooperate or conflict. The three experiments did not support a phonetic interpretation of conflicting/cooperating cues for the perception of final stop consonant voicing. (Author/DB)

Research supported by University of Massachusetts Faculty Research Grant, National Institute of Mental Health grant MH-03803-06, and National Science Foundation grant GS-386.

This study examined the equivalence of objects and pictures of objects in transfer discrimination of 72 children (ages 24-45 months). (BRT)