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.     

Wire-bending test as a predictor of preclinical performance by dental students

Traditional Dental Aptitude Test and academic grade point average have been shown to be poor predictors of clinical performance by dental students. To refine predictors of psychomotor skills, a wire-bending test was given to 105 freshmen at the beginning of their dental education. Grades from seven restorative preclinical courses in their freshman and sophomore years were compared to scores on wire bending and the three traditional predictors: GPA, academic aptitude, and perceptual aptitude scores. Wire-bending scores correlated significantly with six out of seven preclinical restorative courses. The predictive power for preclinical performance was doubled when wire bending was added to traditional predictors in stepwise multiple regression analysis. Wire-bending scores identified students of low performance. These preliminary results suggest that the wire-bending test shows some potential as a screening test for identifying students who may hae psychomotor difficulties, early in their dental education.     

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.     

Punished and Nonpunished Responding in A Multiple Schedule in Humans: A Brief Report

Four male subjects responded on a multiple schedule in which responding was maintained by a random interval 20-sec (RI20) schedule of point presentation. Responding was suppressed in alternating components by an added variable ratio 30 (VR30) schedule of point subtractions. Each component was accompanied by distinctive stimulus lights. Subjects were exposed to the multiple schedule from the initial session. Two subjects experienced four 50-min sessions daily (Experiment 1) and the other two subjects participated in one 50-min session daily (Experiment 2). Once responding in the punished components had stabilized, responding in the nonpunished components continued to increase across sessions. Nonpunished responding did not stabilize even after as many as 36 sessions. These results are discussed in the context of previous studies using animals which employed multiple schedules with punished and nonpunished response contingencies.

     

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.     

Psychotherapists' religious beliefs and their perception of the psychotherapy process

In a comparison of religious and nonreligious psychotherapists' perceptions of a portion of a psychotherapeutic session no significant differences were found on the Vanderbilt Psychotherapy Process Scale for four groups of therapists designated according to their scores on three religious questionnaires. While the results suggest attitudes toward religion are not reflected in therapists' practice of psychotherapy, limitations of the study indicate the need for more rigorous testing of this possibility.     

The myth of science education

It is argued that the manner in which we teach science in the high schools represents an outdated positivistic conception of science. The standard presentation of a year of each of chemistry, biology and physics should be replaced by an integrated science plus history, philosophy, and sociology of science which would take a total of three years to complete. A proper appreciation for the true nature of science is essential to the continued health of the scientific enterprise.     

The psychological reality of word senses

This paper tests psychologists' frequent assumption that dictionaries are psychologically realistic models of polysemy in the mental lexicon. Psychologists have not often explored the nature of polysemy, and lexicographers' methods have not involved scientific sampling of usages or informants. It is argued, however, that the lexicographic technique of citation sorting is an effective way of discovering sense differences. Here this technique was used in three tasks involving usage samples for 24 high- and low-frequency nouns varying widely in degree of polysemy in the dictionary. Analyses of agreement within and between subjects showed that subjects consistently judged and substantially agreed upon the major senses of most nouns, but that few nouns in either frequency group were perceived to have more than three significant senses. Additionally, the possibility that larger usage samples will bias people to make more sense groupings was found not to be true, suggesting that the larger number of senses lexicographers create for high-frequency words are not artifacts of larger usage samples.This research was partially supported by grants from the Spencer and Sloan Foundations to George A. Miller.     

Memorabeatlia: A naturalistic study of long-term memory

Seventy-six undergraduates were given the titles and first lines of Beatles' songs and asked to recall the songs. Seven hundred and four different undergraduates were cued with one line from each of 25 Beatles' songs and asked to recall the title. The probability of recalling a line was best predicted by the number of times a line was repeated in the song and how early the line first appeared in the song. The probability of cuing to the title was best predicted by whether the line shared words with the title. Although the subjects recalled only 21% of the lines, there were very few errors in recall, and the errors rarely violated the rhythmic, poetic, or thematic constraints of the songs. Acting together, these constraints can account for the near verbatim recall observed. Fourteen subjects, who transcribed one song, made fewer and different errors than the subjects who had recalled the song, indicating that the errors in recall were not primarily the result of errors in encoding.