Geometric and semantic similarity in visual masking

Semantic and geometric or physical similarity were manipulated separately in a backward-masking situation. When the target was a word to be read aloud, formal similarity between the letters of target and mask facilitated target recognition, as did associative similarity. Masking a target word by its own anagram also facilitated whole word report. In contrast, formal similarity was inhibitory rather than facilitatory of report when the target was spelled letter-by-letter, rather than read whole. This was true even for the same target words whose whole report was facilitated by formal similarity. A model to account for this reversal in the broader context of the neural substrate of reading is advanced. It is proposed that letter and word processing are fundamentally different in that letters are recognized by hierarchical feature analysis while words are stored and recognized wholistically by diffuse and redundant networks. Implications of the results for the study of reading are discussed.     

A CULTURAL DIFFERENCE IN VISUAL MEMORY: ON LE VOIT,ON NE LE VOIT PLUS

Further to the debate between Kearins (1978) and Drinkwater (1978), visual memory skills of Aboriginal and white Australian children were examined using Drinkwater's version of Kim's game with desert Aboriginal and rural white children. Older children remembered more than younger ones, and Aboriginal children recalled more natural objects than white children. There was no difference between the groups in recall of manufactured objects, nor between recall of manufactured and natural objects within each group. Aboriginal children remembered significantly more objects overall than white children when the task was first administered. On a second occasion, after a procedure designed to orient children towards the use of predominantly visual rather than verbal memorising strategies, there was no significant difference between the groups.     

The intuitive personologist revisited: A critique of dialectical person perception

A critical examination of dialectical person perception as advanced by Lamiell, Foss, Trierweiler, and Leffel, (1983) reveals some important problems both in its empirical basis and in the underlying model of the intuitive personologist. The present article discusses these problems and suggests some alternative conceptions of the intuitive personologist.     

Discrimination and generalization by rats of temporal stimuli lasting for minutes

In three experiments, rats learned to respond differentially to reinforced and nonreinforced trials when the length of the intertrial interval (ITI) predicted the trial outcome (reinforcement or nonreinforcement). Rats in control groups, for whom the length of the ITI did not predict the outcome, did not show differential performance on nonreinforced and reinforced trials. Generalization gradients obtained following discrimination training were comparable to those obtained following discrimination training with other types of discriminative stimuli. That is, groups which had shown differential performance in discrimination training yielded generalization gradients with fastest speeds at the previously reinforced ITIs, slowest speeds at the previously nonreinforced ITIs, and intermediate speeds at ITIs of intermediate length. Control groups yielded flat gradients across all ITIs tested. These effects were shown for relative time discrimination (short time = reinforcement, long time = nonreinforcement, or the reverse) and also for an absolute time discrimination (long and short time = reinforcement, middle time = nonreinforcement or the reverse). This method was effective for time duration measured in minutes rather than seconds, as is more commonly the case.     

Activity of wrist muscles elicited during imposed or voluntary movements about the elbow joint

To examine the coordination of muscles during multijoint movement, we compared the response of wrist muscles to perturbations about the elbow joint with their activation during a volitional elbow movement. The purpose was to test the following two predictions: (a) Responses can occur in muscles not stretched by the perturbation, as has been reported for other multijoint systems; and (b) the motor pattern in response to a perturbation mimics an opposing volitional motor pattern across the two joints. We recorded the electromyographic (EMG) activity of elbow and wrist muscles as well as the flexion/extension motions at the elbow and wrist joints during individual trials that either involved a response to a torque perturbation that extended the elbow or required volitional elbow flexion. The results of this study confirmed that responses were elicited in the nonstretched wrist muscles when the elbow joint was perturbed. The same motor sequence of elbow and wrist flexors was present for both the volitional and perturbation task (with the forearm supinated), regardless of whether the wrist joint was immobilized or freely moving. The findings suggest that the nervous system relies on the purposeful coupling of elbow and wrist flexors to counter the inertial effects during the unrestricted voluntary movement, even though the coupling does not appear to be purposeful during the perturbation or with the wrist immobilized. The coupling of elbow and wrist flexors, however, was not rigidly fixed, as evidenced by muscle onsets that adapted over repeated perturbation trials and a reversal of the wrist muscle activated (wrist extensor) when the forearm was pronated. Hence, the coupling of muscle activities can be modified quantitatively when not beneficial and can be altered qualitatively with different initial configurations of the arm.     

Manifest needs of prospective counselors: a comparative study

Mean performances of 81 prospective counselors on each of the Edwards Personal Preference Schedule (EPPS; Edwards, 1959) needs were analyzed and statistically compared with performances of elementary school counselors, other school counselors, urban college students, professional women, Roman Catholic sisters, and the 1959 EPPS norm samples. Performances of the men and women in the prospective counselor group were similar. Men had a significantly higher need for achievement and dominance, but the significance did not reach .01. Two EPPS needs, intraception and nurturance, consistently differentiated the prospective counselor group. Comparisons across samples indicated that prospective counselors were most similar to the two counseling samples and, for the female subgroup of prospective counselors, to the sample of professional women. Largest across-sample differences were found between the female prospective counselors and the Roman Catholic sisters, between the female prospective counselors and norm samples of female college students and female adults, and between the male prospective counselors and the male adult norm sample.     

Intelligence and race: further comments on J. P. Rushton's work.

A review of some implications of J.P. Rushton's 1988 and 1990 work on racial differences in brain mass (size or weight) suggests that his comments do not constitute a viable scientific theory.     

Manual discrimination of force using active finger motion

In these experiments, two plates were grasped between the thumb and forefinger and squeezed together along a linear track. An electromechanical system presented a constant resistance force during the squeeze up to a predetermined location on the track, whereupon the force effectively went to infinity (simulating a wall) or to zero (simulating a cliff). The task of the subject was to discriminate between two alternative levels of the constant resistance force (a reference level and a reference-plus-increment level). Results of these experiments indicate a just noticeable difference of roughly 7% of the reference force using a one-interval paradigm with trial-by-trial feedback over the ranges 2.5≤F _o≤10.0 newtons, 5≤D≤30 mm, 45≤S≤125 mm, and 25≤V≤160 mm/sec, whereF _o is the reference force,D is the distance squeezed,S is the initial finger-span, andV is the mean velocity of the squeeze. These results, based on tests with 5 subjects, are consistent with a wide range of previous results, some of which are associated with other body surfaces and muscle systems and many of which were obtained with different psychophysical methods.