Field independence and laterality in the perception of faces.

For a sample of 28 college males the degree of left visual-field bias in the perception of faces correlated .45 (p less than .01) with extent of field-independent performance, as assessed by a composite score based on the Embedded-Figures Test, the Rod-and-Frame Test, and ratings on the Articulation-of-Body-Concept Scale. In a second study with 16 female and 10 male college subjects using the Group Embedded-Figures Test, field-independent subjects again showed greater left visual-field lateralization of face perception (r = .43, p less than .05). Based on Witkin's view of field independence as a manifestation of psychological differentiation, possible links between extent of differentiation at the psychological and neurophysiological levels are suggested.     

Effects of concurrent verbal memory on recognition of stimuli from the left and right visual fields.

Two experiments examined the effect of concurrently holding 0, 2, 4, or 6 nouns in memory on the recognition of visual stimuli briefly presented to the left or right visual fields. When stimuli to be visually recognized were complex visuospatial forms it was found that a relatively easy memroy load of 2 or 4 nouns improved visual recognition accuracy on right visual field (left-hemisphere) trials relative to the no-memory condition; however, a more difficult memory load of 6 nouns decreased visual recognition accuracy to a level slightly below the no-memory condition. There were no effects of concurrent verbal memroy on visual form recognition on left visual field (right-hemisphere) trials. When the stimuli to be visually recognized were words it was found that a relatively easy memroy load of 2 or 4 nouns improved visual recognition accuracy and a more difficult load of 6 nouns decreased visual recognition accuracy on both left and right visual field trials. The complete pattern of results indicates that several factors including cerebral hemisphere specialization, stimulus codability, selective perceptual orientation, and selective cerebral hemisphere interference interact in systematic ways to produce overall visual laterality effects.     

The rod-and-frame illusion in erect and supine observers

Previous studies have found that the effect of a tilted frame on egocentric rod adjustments is greater when an overhead display in a horizontal plane is viewed from a supine body position than when a vertical display is viewed from an erect body position. The present studies were designed to see whether this phenomenon could be attributed to an intravisual orientation contrast effect or to the effects of visually induced eye torsion. No significant erect-supine differences were found on measures of either effect. Errors in the direction of frame tilt were significantly greater in the supine position when observers were asked to align a visible rod or an unseen hand-held disk with the head, but no effect of body position was found in matching the orientation of the disk with the rod. The data suggest that erect-supine differences in frame effects are not attributable simply to intravisual factors. The results are discussed in terms used by Harris (1974) to describe “straight-ahead shifts” in judging spatial directions with respect to the median plane.     

Frequency of occurrence and concreteness ratings of homograph meanings

The purpose of this research was to establish norms for the relative frequency of use of the different meaning of common homographs (words that have one spelling but two or more distinctly different meanings) and to present ratings of the concreteness-abstractness of those meanings. A total of 108 subjects wrote a phrase or sentence using each of 120 homographs that were presented at a 15.5-sec rate. For each homograph, norms are provided indicating the relative frequency with which each meaning was used by men and by women. In addition, four judges rated the concreteness-abstractness of each meaning. These ratings are also provided, as are the means of the overall concreteness for each homograph.     

Category and Attribute Knowledge Deterioration in Alzheimer's Disease

A prevalent theory regarding the deterioration of semantic memory in Alzheimer's disease is that it is a bottom-up process. If this is true, performance on tests of attribute knowledge should decline more rapidly than performance on tests of categorical knowledge as dementia severity increases. In the present study, a convincing pattern of findings to either support or reject the theory failed to emerge. This raised questions regarding the ability to separate attribute and categorical knowledge, and whether one can be tested without influence of the other. Questions also were raised regarding the additional cognitive processes needed to complete tasks of semantic memory.     

Dexamethasone Does Not Prevent Seven-Day ADX-Induced Apoptosis in the Dentate Gyrus of the Rat Hippocampus

Long-term adrenalectomy (ADX) is known to result in apoptosis within the dentate gyrus of the rat hippocampus. While the underlying mechanism is still unclear, adrenal steroids appear to play a pivotal role in granule cell survival, as administration of the mineralocorticoid receptor (MR) agonists, corticosterone and aldosterone, to ADX rats results in protection against the ADX-induced effect. The consequence of administration of the glucocorticoid receptor (GR) agonists, dexamethasone and RU28362, however, is less clear, and either complete or only partial protection for the ADX animal has been reported. This study investigated further the role played by GR in the degenerative process. After establishing the characteristics of seven-day ADX-induced apoptosis in the young male Wistar rat, the effect of chronically-implanted, subcutaneous pellets containing various doses of dexamethasone and corticosterone, on ADX-induced apoptosis was studied. Both high and low doses of corticosterone were found to be protective. In contrast to some other studies, however, neither dose of dexamethasone had any obvious protective effect and rather seemed to increase apoptosis in dentate gyrus of intact animals. Intracerebroventricular infusion of dexamethasone for seven days was also found to be ineffective in preventing apoptosis, demonstrating that it is occupation of MR, rather than GR, which is crucial to dentate gyrus granule cell survival.     

Exploratory Factor Analysis: A Users’Guide

In 1978, Comrey wrote a guide to factor analysis in the Journal of Consulting and Clinical Psychology. This paper provides an update of the information given by Comrey in relation to exploratory factor analysis (EFA) for work and organizational psychologists, and particularly those involved with test development, interpretation and validation. In doing so, it offers a user's guide to contemporary methods and available techniques and introduces heuristics for dealing with problems of skew and kurtosis, social desirability response set, and factor naming.