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…

This study investigated the effects of tact prompts on the acquisition and retention of divergent intraverbal responding to categorical questions involving conditional discriminations. A 6-year-old boy with autism participated in the study. A multiple probe design across behaviors was used. A tact-prompt procedure was implemented. The results…

Two experiments tested whether a peak-shifted generalization gradient could be explained by the averaging of distinct gradients displayed in subgroups reporting different generalization rules. Across experiments using a causal judgment task (Experiment 1) and a fear conditioning paradigm (Experiment 2), we found a close concordance between…

Advocates of modality preference posit that individuals have a dominant sense and that when new material is presented in this preferred modality, learning is enhanced. Despite the widespread belief in this position, there is little supporting evidence. In the present study, the authors implemented a Morse code-like recall task to examine whether…

Thirty college students attempted to form three 3-node 5-member equivalence classes under the simultaneous protocol. After concurrent training of AB, BC, CD, and DE relations, all probes used to assess the emergence of symmetrical, transitive, and equivalence relations were presented for two test blocks. When the A-E stimuli were all abstract…

Variation in baseline controlling relations is suggested as one of the factors determining variability in stimulus equivalence outcomes. This study used single- comparison trials attempting to control such controlling relations. Four children learned AB, BC, and CD conditional discriminations, with 2 samples and 2 comparison stimuli. In Condition…

We tested whether teaching control by single stimulus samples in conditional discriminations would result in common control of two-stimuli compound samples, and vice versa. In Experiment 1, 5 participants were first taught four single-sample conditional discriminations. The first conditional discrimination was as follows: given sample stimulus P1,…

Twenty-seven 4-month-old infants heard a repetitive auditory rhythm, then viewed silent film of puppet opening/closing its mouth, either in the familiar rhythm or a novel rhythm. Results showed infants exposed to the novel condition watched the film longer than infants shown the familiar condition, providing evidence for auditory-visual transfer…

Five experiments were performed to identify the basic Spanish colour categories (BCCs) and to locate them in the CIE L*u*v* space. The existence of 11 BCCs was confirmed using an elicited list task and a free monolexemic naming task. From the results provided by a synonymicity estimation task, it was concluded that, in Spanish, 2 synonymous terms…

The single-stimulus (SS) preference assessment procedure has been described as more appropriate than the paired stimulus (PS) procedure for "lower functioning" individuals, but this guideline's vagueness limits its usefulness. We administered the SS and PS preference assessment procedures with food items to seven individuals with severe…

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…

The current study consisted of 2 parts, with the same 4 normally developing 4-yr-old children employed across both parts. The primary aim of Part 1 was to replicate previous research on exemplar training and its impact upon the emergence of repertoires of derived symmetry or mutually entailed relations. In this part of the study, the children were…

Data suggest that human newborns are capable of making a chromatic discrimination within the spectral region above 540 nm (the Rayleigh region), but their ability is limited to chromatic stimuli of very wide spectral separation and of very large size. Possible neurological bases underlying this immaturity are discussed. (RH)

Three autistic boys (ages 9-13) were trained to select a card containing a stimulus array comprised of three visual cues. Decreased distance between cues resulted in responses to more cues, increased distance to fewer cues. Distances did not affect the responding of children matched for mental and chronological age. (Author/JW)

Discrimination learning set performance was examined in preschool children as a function of age and number of trials per problem. Subjects were 120 children three, four, five, and six years old. (MP)