A two-dimensional computer-controlled visual stimulator

A computer-controlled instrument that creates complex two-dimensional patterns on a CRT monitor is described. These patterns are used to elicit visual evoked responses. Patterns are produced on a raster that is rotatable about its center. It is possible to assign to arbitrary regions in the raster any of four independent one-dimensional spatial-temporal functions. For each spatial-temporal function, the experimenter can select an arbitrary spatial profile, the spatial frequency of the profile, the starting phase of the profile, the temporal function, and the depth of modulation.     

Development of visual stimulus-seeking in kittens

Three studies of the development of stimulus-seeking kittens are reported. In Experiment I kittens were housed, from before eye-opening, in total darkness or in a normal laboratory environment. They were given the opportunity, for one hour each day, to press a panel to illuminate a pattern in an otherwise dark experimental chamber. The normally-reared kittens scarcely availed themselves of this opportunity throughout the experiment. In contrast, the dark-reared kittens showed a sudden onset of visual stimulus-seeking around the end of the second month and thereafter pressed the panel for extended periods. This behaviour was maintained for as long as the cats were kept in the dark. In Experiment II, kittens were given varying periods of normal visual experience before being housed in the dark. The results showed that onset of stimulus-seeking was age-dependent and required only that the animals be housed in darkness at or after the end of the second month. Experiment III showed that stimulus-seeking did not extend to auditory stimuli and also that moving and stationary visual stimuli were equally effective in promoting the phenomenon. It is suggested that visual stimulus-seeking is one aspect of the maturation of a system underlying visual approach and exploratory behaviour. Evidence bearing on this point is discussed.     

Visual information processing in the left and right hemispheres during unilateral tachistoscopic stimulation of stutterers

Tachistoscopy was used to investigate 42 stutterers and a corresponding control group for their speech dominance. A bilateral cortical responsibility for speech was equally frequent in the two groups. However, 2.5 times as many stutterers showed a superiority in the information processing in the right hemisphere than did nonstutterers.     

Sense of Closeness to Parents and Family Rules: A Study of Arab and Jewish Youth in Israel

The present study investigated adolescents' perception of closeness to their parents and family rules restricting their conduct, in Arab and Jewish Israeli samples. A total of 854 11th-grade high school students reported their perceptions by a self-report questionnaire. Overall, the results indicate that the Arab youths perceived more closeness toward their parents and more rules restricting their conduct, compared with their Jewish counterparts. In both cultures, girls reported more restrictions on dating and leaving home than boys. Among Israeli Arab adolescents a positive association was uncovered between closeness to parents and number of rules. No such pattern was evident among Israeli Jewish youth. These and additional findings are discussed within the context of Triandis' cross-cultural dimension of collectivism-individualism.     

Item Variances and Median Splits: Some Discouraging and Disquieting Findings

ABSTRACT In his response to our article, Baumeister argued that in real data, the confound between interitem variance and trait extremity is small (typically in the range of 0 and –.2), and that the danger of artifact associated with the application of median splits to interitem variance is not as serious as our first simulation study would lead one to believe. When we examined a large body of actual personality data, employing personality scales of average reliability and relatively large samples, we found that the average magnitude of the confound was –.15. However, we also found that even a confound as small as –.03 could be associated with significant differential range restriction of the trait scores within subsamples produced by the median split (MS) technique. We note that several factors, not just the magnitude of the interitem variance/trait extremity confound, must be considered when assessing the danger of artifact associated with the MS technique. We again conclude that researchers should use the moderated multiple regression (MMR) technique in preference to the MS technique when testing for moderating effects in personality research.     

The etiology of schizophrenia as perceived by psychiatrists in Europe and the United States

This paper compares and contrasts statements made by American and European psychiatrists on the etiology of schizophrenia. In the U.S., leading figures in psychiatry hold increasingly to the view that the disorder is physiogenic at source—from which it seems to follow that the appropriate treatments should similarly focus on physiological and pharmacological therapies. In contrast, European psychiatrists seem to be divided in support for organic and psychodynamic explanations. Some European writers have pointedly warned against over-interpreting recent studies which seem to point to specific organic dysfunctions and deficits as schizophrenogenic. This paper was presented at the Second Annual Convention of the American Psychological Society, Dallas, Texas, June 7–10, 1990.     

Paradoxical choice and the reinforcing value of information

Animal Cognition - Signals that reduce uncertainty can be valuable because well-informed decision-makers can better align their preferences to opportunities. However, some birds and mammals display...