Using a conditioned suppression task, we investigated simultaneous (XA-/A+) vs. sequential (X [right arrow] A-/A+) Feature Negative (FN) discrimination learning in humans. We expected the simultaneous discrimination to result in X (or alternatively the XA configuration) becoming an inhibitor acting directly on the US, and the sequential…

While many studies have investigated duration discrimination in human adults and in nonhuman animals, few have investigated this ability in infants. Here, we report findings that 6-month-old infants are able to discriminate brief durations, and, as with other animal species, their discrimination function is characterized by Weber's Law:…

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…

Two experiments investigated baseline reviews as a relevant variable in reorganization of equivalence classes. After formation of three 4-member classes, participants learned reversals of baseline conditional discriminations and expanded the classes to 5 members each. In Experiment 1, 4 students responded on equivalence probes without baseline…

The ability to report the temporal order of 2 tactile stimuli (1 applied to each hand) has been shown to decline when the arms are crossed over compared with when they are uncrossed. However, these effects have only been measured when temporal order was reported by stimulus location. It is unknown whether this spatial manipulation of the body…

This experiment evaluated the contributions of frequency and contingency of reinforcement to the deprivation-satiation phenomenon. The findings indicated that the perceived contingency of reinforcement is a more powerful determinant of its subsequent reinforcement effectiveness than is its frequency. (JMB)

Investigated the effect of correction and noncorrection procedures on the occurrence of the overlearning reversal effect (ORE) in 80 children 4-6 years of age. Results showing the existence of ORE at the preschool level are explained in terms of a response-switching strategy. (GO)

The results of the experiment demonstrated that Down's syndrome children are equal to non-disabled children matched on mental age, in their ability to discriminate between colors. Both Down's syndrome and non-disabled children made errors of the same kind. Other undifferentiated mentally handicapped children are less consistent in their color…

Four low-functioning mentally retarded subjects learned conditional discrimination performance in two-comparison auditory-visual and visual-visual identity matching-to-sample paradigms. Results suggested that acquisition of both positive and negative conditional relations may occur when developmentally limited individuals are trained wth…

Ten autistic children and 10 normal nursery school children, matched for mean developmental age, were presented with figure stimuli and had variable irrelevant cues in two-choice simultaneous discrimination learning. Performance of the autistic group did not vary as a function of irrelevant variability, a result attributed to poor performance of…

A go/no-go conditioned head-turn paradigm was used to examine the abilities of 6- and 12-month-olds to discriminate changes in temporal grouping and their perception of absolute and relative timing information when listening to patterns of white-noise bursts. (Author/RH)

Responses of symbol-naive and symbol-experienced severely mentally retarded persons to traditional orthographic letters and lexigram elements were compared. Overall, Ss's reponses to lexigrams were more accurate and faster than were responses to more complex combinations. It was concluded that perceptual features of lexigrams are easier to…