Development of classification: The use of similarity and dimensional relations

Findings about perceptual development indicate that overall similarity is the primary perceptual relation by which young children compare complex objects. Traditional studies of classification, however, did not focus on children's organizational use of holistic relations but rather on their ability to classify by dimensions or criterial attributes. The results from such traditional studies suggest that young children are deficient classifiers. The present research investigated the possibility, contrary to the traditional view, that 4- to 6-year-old children are competent and systematic classifiers at least by overall similarity. In three experiments, preschoolers and kindergarteners classified various sets of multidimensional stimuli that could be organized into categories by overall similarity or by dimensional attributes. Consistent with the research in perceptual development, the children were highly attentive to overall similarity. However, the preschoolers in particular showed marked difficulty in using this relation to form categories of more than two objects. The children's difficulties were highly reminiscent of traditional claims about early classification. Analyses of the classification strategies used by the children, however, suggest that even the youngest children understood the purpose of a classification. The developmentla changes appear to be in the ability to execute a classification. Importantly, type of classification strategy was independent of type of category organization. Individual children used the same strategies both when classifying by overall similarity and by dimensional attributes. These results strongly suggest that it is the classification skills themselves, and not just the ability to classify by particular relations, that change with age.     

Cross-modal transfer and intermediate-size transposition

Kindergarten and third grade boys learned an intermediate-size problem either visually or tactually. They were then tested either visually or tactually. The test sets were separated from the training set by either 1, 2, or 4 steps. The data supported predictions derived from the D. M. Lane and F. M. Rabinowitz (Child Development 1977,48, 412–426) transposition theory on choice and consistency measures. Of greatest interest were the markedly different transposition gradients exhibited by the boys in the visual-visual and visual-tactual groups.     

Modality-specific information processing and intellectual ability

Two groups of children, one of below average intelligence and one of above average intelligence, were adminitered nine tasks involving matching information between auditory and visual modalities and temporal and spatial presentations. The below average intelligence children made more matching errors than the above average intelligence group, with no indication that matching problems were particular to one modality or particular to cross-modal as opposed to intramodal matching. Factor analyses did suggest, however, that matching processes varied according to levels of intelligence. The results are discussed in terms of the differences between modality-specific and nonmodal theoretical views of sensory systems, and it is noted that neither view alone is adequate to account for the variations found for the two intelligence groups. It is suggested that the results are consistent with Luria's research on neurological organization.     

Constraints on Pavlovian aversive conditioning: Implications for avoidance learning in the rat

Four experiments investigated the relative degree of control exerted by several conditional stimuli when each stimulus: (a) preceded shock, (b) followed shock, and preceded a shock-free interval, (c) was independent of shock, or (d) was novel. When the onset of an auditory stimulus had preceded shock (Experiments 1, 2A, and 3), it always exerted conditioned excitatory control. When the same stimulus preceded a shock-free interval, it never exerted conditioned inhibitory control. When the onset of light (Experiments 2B, 4), silence (2C), or darkness (1, 2D) preceded a shock-free interval, it always exerted conditioned inhibitory control. However, when one of the latter stimuli preceded shock, it failed to exert excitatory control. Several models of this phenomenon were tested. The implications of these results for the species-specific defence reaction and two-factor theory accounts of avoidance learning were outlined.     

An examination of the Fishbein-Ajzen behavioral-intentions model's concepts and measures

The Fishbein-Ajzen behavioral-intentions model is designed to represent the effect of attitudes and subjective norms on behavioral intentions. The model has been used in a variety of contexts, and evidence for its validity flows largely from its generally good performance in predicting behavioral intentions. However, the manner in which these concepts are defined and operationalized appears to make it inappropriate for those seeking to distinguish between personal and normative reasons for engaging in a behavior. Additional problems were found in the hypothesized relationship between the more global normative construct and its underlying components.     

Therapy and immunization of long-term analgesia in rats

Three experiments are reported which examine the effects of experience with escapable shock either subsequent to (Experiment 1) or prior to (Experiments 2 and 3) a session of inescapable shock on the subsequently produced long-term analgesic reaction in rats. Experment 1 demonstrated that experience with escapable shock 4 hr after a session of inescapable tail shock completely reverses the analgesic response that is normally observed 24 hr later upon reexposure to shock. The escapability of the shock was shown to be the important factor in reversing the analgesic reaction, since subjects given inescapable shock in amounts equivalent to escape subjects exhibited no reduction in analgesia. Experiment 2 showed that experience with escapable shock 4 hr prior to a session of inescapable tail shock could also completely eliminate the long-term analgesic reaction. Experiment 3 replicated the results of Experiment 2, but employed a different escape task and temporal parameters in order to extend the generality of the findings, and to more closely match the procedures employed in behavioral experiments reported by J. L. Williams and S. F. Maier (Journal of Experimental Psychology: Animal Behavior Processes, 1977, 3, 240–253). The implications of these results for the areas of pain control and learned helplessness were discussed.