Detection and discrimination thresholds for auditory periodicity

Complex periodic auditory signals, produced by the Guttman-Julesz procedure of repeating segments of random noise, were employed to address the low region of auditory periodicity. Periodicity detection and discrimination tasks were examined with a common experimental procedure and a common measure of thresholds. Typically, detection and discrimination performance suffer at extremely low periodicities, presumably because of the extremely close spacing of harmonics throughout the auditory spectrum. Interaural phase effects are extremely weak for these signals, being largely confined to threshold-detection tasks. Despite qualitative phenomenological differences for different periodicity regions, detection and discrimination functions show no sharp discontinuities over a wide range of periodicities.     

Cross-gender perceptions of facial attributes and their relation to attractiveness: do we see them differently than they see us?

Examination of perceptions of human facial attributes revealed that individual attributes are similarly perceived by males and females. However, patterns of attribute interrelationships differ as a function of gender of the face. Undergraduate students (N = 280) rated pictures of 40 male or female Caucasians on 12 physical attributes (e.g., nose size, face width) and overall attractiveness. The four sets of attribute ratings (defined by rater gender and picture gender) were submitted to principal components analyses, and five-factor solutions were found for each condition (accounting for about 76% of the variance). Comparisons of the four component solutions using confirmatory factor procedures revealed that male and female raters share one factor structure when rating photographs of female faces and another factor structure when rating photographs of male faces. Multiple regression analyses revealed that the patterns of attribute interrelationships were not "perceptual units" in the perception of attractiveness, and that different "rules" are used to assess the attractiveness of male and female stimuli faces. The importance of these results for models of facial attractiveness and interfacial similarity judgements are discussed.     

How much processing do nonattended stimuli receive? Apparently very little, but...

The early versus late selection issue in attention models was examined by means of a new methodology. Through cues or precues, attention was directed to one location of a multistimulus visual display and, while attention was so engaged, the identity of a stimulus located at a different position in the display was changed. By varying the time after display onset before the stimulus was changed, we controlled the preview time that the original stimulus was represented on the retina. Then, using a marker cue, we directed the subject's attention to the location of the changed stimulus. The subject's response was a timed discrimination between two possible target letters. The data of main interest was the effect of preview time upon the subject's latency in identifying the new target that appeared in the changed location. We found that the preview time of the original stimulus, before RT was affected to the new target, depended upon whether the original stimulus was a neutral (noise) letter or whether it was the alternative target. When the original stimulus was a noise letter, RTs to the new target were just as fast as those obtained in the control condition in which the target was present throughout the preview interval and did not change its identity. Significant effects upon RT were obtained at preview times of 83 msec when the original stimulus was one of the targets that changed to the alternative target. Preview times also varied as a function of precuing. Preview times were correspondingly shortened when the first cue occurred 50 msec before display onset, thus providing an extra 50 msec for attention to be directed to the first display location. The results were interpreted in terms of two separate information-processing systems in the human: an automatic system and an attentional system. Even though a stimulus may have been automatically processed, when the attention system is directed to that stimulus, processing starts at the beginning again.     

Perceptual integration of tertiary taste mixtures

Integration psychophysics was used to explore the taste perception of mixtures of sucrose, fructose, and citric acid. Three levels of each stimulus were varied in a 3 x 3 x 3 factorial design. Subjects rated total intensity, sweetness, and acidity of the 27 mixtures on graphic rating scales. Consistent with earlier work, the perceived total intensity of the tertiary mixtures was found to be dictated by the intensity of the (subjectively) stronger component alone (i.e., either the integrated sweetness or the acidity, whichever was the more intense). In contrast, the sweetness and acidity of the mixture were susceptible to mutual suppression: Sweetness suppressed acidity, acidity suppressed sweetness. There was, however, a difference between sucrose and fructose in their interactions with citric acid, fructose being the more susceptible to suppression. This selectivity of suppression indicates that the two sweetnesses could not have been inextricably integrated. Implications for taste coding are discussed, and the findings are reconciled in terms of two separate coding mechanisms: one for taste intensity, another for taste quality.     

Insulin and dextrose effects on fixed-interval behavioral thermoregulation in albino rats

This study is a systematic replication of the effects of insulin doses on operant behavior reinforced (in an earlier study) by fixed-ratio schedules of microwave (MW) reinforcement. In this study, insulin and dextrose doses were administered (ip) prior to fixed-interval 2-min. schedules of MW reinforcement in rats tested in a cold environment. Six Sprague-Dawley rats were conditioned to regulate their thermal environment with 5-sec. exposures of MW radiation (SAR = 0.34 Watts/kg/(mW/cm2) under the FI-2' schedules. Humulin-regular insulin and 50% solutions of dextrose were administered (ip) alternately with saline control sessions for 8-hr. durations. A within-subjects, repeated-measures 4 x 8 x 3 factorial analysis of variance design showed that insulin doses suppressed operant responding for heat, which confirmed the results of the earlier study under a different schedule. In addition, high doses of dextrose had similar suppressing effects on operant responding for heat. The data are interpreted in terms of the discriminative properties of increased thermogenesis produced by the insulin and dextrose doses. The suppressing effects were more pronounced for the first two hours, yet they persisted for approximately six hours of the 8-hr. sessions.     

Clinical multiplicity of cerebrovascular disorders in childhood

A group of 107 children with vascular diseases of the nervous system aged 3-14 years have been studied. In 100 children of the study group acute disturbances of the brain blood circulation have been found, out of which 37 children were with transitory ischemic attacks; 29 were found to be with brain ischaemia; 22-with haemorrhages (7 cases with subarchnoidal, 9 cases with intracerebral and 6 cases with subarachnoidal-parenchimatose); 5 children had wenous thromboses; 7 children were with spinal strokes. In other 7 children we found the presence of Sturge-Weber syndrome. Congenital vascular malformations have been found in 32 children (30%), out of which 16 children (15%) with loops and stenosis of the extracranial segments of the internal carotid artery, and another 16 children (15%) with AV-malformations. Congenital and acquired heart diseases are found to be primary cause for the strokes in 12 children (11%). Considerable is the rate of the epileptic seizures in the acute stage of the strokes as well as of the residual epileptic syndromes.     

Birth order and fear of success among midadolescents

While among 194 high school students 79 first-borns showed less fear of negative consequences of academic success than 78 last-borns and 37 middle-borns, no differences were observed on fear of increased positive attention or of increased responsibility.     

Differential effects of pet presence and pet-bonding on young children

Pets have been shown to influence human development, but whether the effect is due to the presence of a pet or to the person's relationship with a pet is uncertain. Mothers rated their young children's companion animal bond (relationship) and social competence on a parental questionnaire, and a researcher assessed the children's empathy, cooperation, and intelligence during home visits. Significant correlations were noted between the children's bonds with their companion animals and their scores on the social competency scales as well as their empathy scores. The lack of similar significant pet presence ("ownership") correlations supports the hypothesis that the children's relationships with their pets are more important than just the presence of one or more pets in their homes.     

Bulimia nervosa: group behavior therapy with exposure plus response prevention

Exposure plus response prevention has been demonstrated to be effective in the treatment of bulimia nervosa. However, when done individually, it is labor intensive and cost-ineffective. In the present study exposure plus response prevention was used in the context of a 6-wk., 12-session behavioral group. In addition to the exposure plus response-prevention component, other techniques included self-monitoring, cognitive restructuring, eating-habit stabilization and problem-solving. Eight bulimic women, vomiting a minimum of five times per week for at least a year, participated in the group. At the end of treatment significant reductions in bingeing and vomiting behaviors were reported by all but one subject, substantiated by significantly lower depression scores (Beck Depression Inventory) and binge-eating scores (Binge Eating Scale). At 6 mo. and 1 yr. posttreatment, 6 of 8 subjects reported averaging less than one binge-purge episode per week, one subject continued unchanged, and one subject had relapsed. A group of wait-list control subjects reported essentially no change in binge-purge frequency over the treatment period. Exposure plus response prevention conducted in a behavioral group context appears to be a cost-effective alternative to individual treatment.