A shift in generalization gradients away from S+ and towards stimuli on the opposite end of the stimulus dimension from S- is a well established phenomenon in the laboratory, occurring with humans and nonhumans and with a wide range of stimuli. The phenomenon of gradient shifts has also been observed to have an analogous relationship to a variety…

According to the composite-stimulus control model (Weiss, 1969, 1972b), an individual discriminative stimulus (S[superscript D]) is composed of that S[superscript D]'s on-state plus the off-states of all other relevant S[superscript D]s. The present experiment investigated the reversibility of composite-stimulus control. Separate groups of rats…

This study investigated conditions leading to contextual control by stimulus topography over transfer of functions. Three 4-member stimulus equivalence classes, each consisting of four (A, B, C, D) topographically distinct visual stimuli, were established for 5 college students. Across classes, designated A stimuli were open-ended linear figures,…

In three experiments, match-to-sample procedures were used with undergraduates to establish arbitrary relational functions for three abstract visual stimuli. In the presence of samples A, B, and C, participants were trained to select the smallest, middle, and largest member, respectively, of a series of three-comparison arrays. In Experiment 1,…

Subjects of 4, 5, 7, and 20 years of age performed a speeded classification task designed to isolate sources of interference in visual selective attention. While subjects of all ages were unable to avoid processing distractors, older subjects were better able to inhibit distractor processing. (RH)

Hearing-impaired 6- to 13-year-olds (N=24), trained to discriminate between two stimulus complexes differing in shape, direction, and number, were asked to discriminate between individual characteristics in all possible pair combinations. General failure to respond to all characteristics equally suggested that hearing-impaired children tend to be…

Tests the effects of stimulus variability on overgeneralization and overdiscrimination errors in children and adults. The subjects (n=64), adults and five-, seven-, and nine-year-old children, participated in a visual discrimination task. (CM)

The influence of frequency of occurrence of a visual stimulus on encoding processes is investigated, to discover what mechanisms allow cognitive processes to modify perceptual processes. Six experiments are described and the results are discussed. (MH)

A comparative assessment of eight normal and eight psychotic children in a stimulus generalization paradigm using simple and complex figures. Six of the subjects fulfilled the criteria for infantile autism. (CM)

Three studies explored whether children's tendency to extend object names on the basis of sameness of shape (shape bias) is specific to naming. Findings indicated that 2- and 3-year-olds showed shape bias both when asked to extend a novel name and when asked to select an object of the same kind as a target object; 3-year-olds also showed shape…

Looking times of 36 children were recorded during subject-controlled presentation of slides in order to determine whether the existence of simple categories in 3-year-olds can be inferred from habituation data, and to determine any sex differences in conceptual generalization of habituation. Habituation was demonstrated over repeated presentation…

Tested a normally developing child several times between 16 and 27 months of age for his ability to derive the relations between stimuli. Found that the child derived "mutual entailment" relations and showed "nonverbal exclusion" as early as 17 months. "Combinatorial entailment" relations and "verbal…

In a permanently changing environment, it is by no means an easy task to distinguish potentially important events from negligible ones. Yet, to survive, every animal has to continuously face that challenge. How does the brain accomplish this feat? Building on previous work in "Drosophila melanogaster" visual learning, we have developed an…

The effect of stimulus familiarity on the comprehension of polar adjectives by preschool children was examined by administering a perceptual judgment task. The children's ability to indicate the correct object illustrating a particular word was assessed. Antonyms representing opposite dimensions of quantity, height, length, or size were presented.…

This study assesses the effects of visual and verbal rehearsal on the problem solving efficiency of preschool children. The study examines the use of stimulus pretraining designed to induce verbal rehearsal and compares the effectiveness of induced verbal rehearsal with the effectiveness of induced visual rehearsal. Fifty-four middle class…