Electrophysiological and behavioral indicants of selective attention to multifeature gratings

The mechanisms underlying selective attention to gratings consisting of a particular conjunction of spatial frequency and orientation were investigated by means of both visual evoked potential (VEP) and behavioral measures. The effects of selective attention upon the VEP indicated two general types of selection processes: one which is specific to the features contained in the relevant gratings and is most pronounced approximately 225 msec post-stimulation, and another which is specific to the conjunction of features defining the relevant grating and is most pronounced 250–375 msec following the presentation of the stimulus. The behavioral responses primarily reflected this latter, or grating-specific, attentional process. The results are discussed in terms of the role of sensory feature channels in mediating selective attention to visual stimuli and are related to various information processing models of visual pattern selection.     

The influence of relative frequencies of pure and mixed stimuli on mixture suppression in taste

In experiments on saltiness suppression in NaCL-sucrose mixtures, the amount of suppression depends not only on the suppressing sucrose component in the mixture, but also on the relative frequencies of pure NaCL stimuli and mixed stimuli in the series. The observed variation of mixture suppression as a function of these frequencies can be explained by Helson’s adaptation level theory.     

The effect of flanking context on visual classification: The joint contribution of interactions at different processing levels

Flanking characters that surround a target character may cause either facilitation of or interference with target classification, depending on experimental context. In three different experiments, the patterns of facilitative priming and interference were shown to change systematically as a function of onset asynchrony between flankers and target, illustrating differing time courses of the overlapping processes that each contributes to overall reaction time performance.     

Power functions of loudness magnitude estimations and auditory brainstem evoked responses

The correspondence between subjective and neural response to change in acoustic intensity was considered by deriving power functions from subjective loudness estimations and from the amplitude and latency of auditory brainstem evoked response components (BER). Thirty-six subjects provided loudness magnitude estimations of 2-sec trains of positive polarity click stimuli, 20/sec, at intensity levels ranging from 55 to 90 dB in 5-dB steps. The loudness power function yielded an exponent of .48. With longer trains of the same click stimuli, the exponents of BER latency measures ranged from -.14 for wave I to -.03 for later waves. The exponents of BER amplitude-intensity functions ranged from .40 to .19. Although these exponents tended to be larger than exponents previously reported, they were all lower than the exponent derived from the subjective loudness estimates, and a clear correspondence between the exponents of the loudness and BER component intensity functions was not found.     

Encopresis in adolescence: two case studies.

Encopresis is an underreported psychopathological symptom of adolescence, not necessarily defining a specific diagnostic entity. The two cases presented offer an opportunity to evaluate encopresis occurring in markedly different adolescent pathological entities and developmental backgrounds. The first patient presented a longitudinal life course wherein toilet training and fecal considerations were prominent throughout his development. Indeed, this young man had such areas of cohesive functioning, as to be appropriately considered within the range of characterological pathology, severe, though it may be. In marked contrast, the second patient's encopresis represented but a small part of a totally encompassing psychotic disintegration.     

A group behavior modification approach to adolescent obesity

This article describes a group weight control project with severely obese adolescent girls in a medical setting. Behavior modification and nutritional principles were utilized with peer group interaction. Significant others were included through separate group meetings. This approach produced small amounts of net weight loss for the girls. The drop-outs continued to have a net gain. As a treatment method, this program was more effective for these girls than previous individual clinic contacts had been. When losing weight, the girls tended to use behavior modification techniques more often, and their diets became more adequate nutritionally. Development of group cohesion was tenuous and temporary. Girls who were functioning more independently appeared to do better in weight loss. Disinterested significant others were preferable to nonsupportive ones. A predictive factor was identified, the girls' perception of control. This was measured by the I-E test. Those with a more internalized perception of control were more likely to continue with the program and more likely to lose weight. Because the patient group was small, findings are tentative. However, this program helped to define particular areas that deserve further exploration.     

Individual differences in reported visual imagery and memory performance.

Seventy high school students completed the Vividness of Visual Imagery Questionnaire (VVIQ). Two months later, the 16 highest scores (low visualizers) and the 16 lowest scores (high visualizers) took part in a memory experiment involving abstract words, concrete words and pictures. Analyses of variance showed that high visualizers were superior to low visualizers on all three kinds of item in short-term recall, whereas they were only superior on the concrete words and pictures in long-term recall. Finally, both groups performed equally well on a subsequent recognition test. The results were interpreted as providing support for the validity of the VVIQ.