Reflex modification in the rat: the inhibitory effects of intensity and frequency changes in steady tones

In laboratory rats (as in humans) a low-intensity tone that precedes a high-intensity burst of noise by approximately 100 ms can reduce the amplitude of the startle reaction elicited by the burst of noise. A series of four experiments with rats investigated the relation between the inhibitory effects of tonal frequency change and the length of the silent period (gap) preceding it. The major findings were the following: (a) A gap in an otherwise continuous pure tone inhibited startle when the gap occurred approximately 100 ms prior to the noise burst. (b) Although an increase in gap duration increased the inhibition afforded by the gap, the maximum inhibition was yielded by gaps of 100 ms and greater; this maximum was equivalent to the inhibition yielded by the presentation of a postgap tone alone. (c) A shift in tonal frequency across a 10-ms gap yielded more inhibition than did the same gap with no frequency shift; again the shift yielded equivalent inhibition to the presentation of the postgap tone alone. (d) An increase in the frequency shift increased inhibition when the shift occurred across a 10-ms gap, but not when the shift occurred across a 100-ms gap.     

A longitudinal study of the development of spatial conceptual ability

During October and November of 1983, three subsamples were selected from three schools in Mesa, Arizona: 34 students in 6th grade, 34 students in 8th grade, and 34 students in 10th grade. A battery of Piagetian-type tasks were individually and randomly administered to each subject. Seven tasks examined projective spatial conceptual abilities, and three tasks examined Euclidean abilities. The same battery of tasks was again administered to the same subjects during November and December of 1984 when all the subjects were in the next grade, that is, 7th, 9th, and 11th. Because of attrition, the number of students tested during the second year were 33, 30, and 28, respectively. To test for significant differences between grade levels, a chi-square one-sample procedure was used. Out of a possible 50 tasks, significant differences were detected in 36 (72%). Those findings, along with an examination of the percentage of students passing each task, support the notion of sequential development of spatial conceptual abilities.     

PRODUCING GENERALIZED JOB INITIATIVE IN SEVERELY MENTALLY RETARDED SHELTERED WORKERS

The development of generalized job initiative was examined with three severely retarded men working in an industrial assembly area of a sheltered workshop. Interventions included discrimination training, role-play training, and self-monitoring. For each participant, training was applied sequentially to three sets of job initiative behaviors. Intensive training was required to establish the first set of job initiative behaviors; however, the second and third sets of job initiative behaviors were learned with only discrimination training. The discussion summarizes the findings and suggests research needed to develop more powerful learning-to-learn paradigms.     

A scale for measuring persistence in children

Persistence and its assessment have been studied since the 1920s. One common approach in measuring persistence has been through testing the subject's ability to solve difficult or monotonous problems. Another approach has been through questionnaires. Although persistence is very important in academic achievement and in the general development of personality, no questionnaires have been developed for measuring persistence in children. The present research concerns the development of such a scale. It includes 40 items and was tested on 322 Israeli children aged 7-13. The internal reliability of the scale (Cronbach alpha) was .66, and the test-retest reliability after 6 months was .77. The scale differentiated active gymnasts from non-gymnasts as well as persistent gymnasts from dropout gymnasts. In addition, significant correlations were found between the scale and the need-persistence measure of the Rosenzweig Picture Frustration Study, Locus of Control, and other measures. We discuss these findings along with the significance of persistence in everyday life.     

Of beasties and butterflies: Evidence for the stability and domain-specificity of individual differences in categorization

Previous research has failed to demonstrate unambiguously the relative stability across time and consistency across tasks of individual differences in categorization, or categorization breadth The present study of categorizing behavior in college students assesses breadth at each of four points in time over a six-week period Results are consistent with an interpretation of breadth as a highly stable individual difference variable, but one that is constrained by the nature of the stimulus sets employed High stability coefficients were observed for each of two redundant tasks In contrast, cross-task consistency indices were generally low Personality correlates of breadth were similarly weak and inconsistent Several variables are suggested that may attenuate the generality of categorization breadth The existence of multiple styles of categorization is discussed