Song frequency as a cue for recognition of species and individuals in the field sparrow (Spizella pusilla)

Estimate the amount of frequency variation that affected individual and species recognition by song in territorial male field sparrows with field playbacks of neighbors' songs lowered in frequency in 6 increments between 324 and 1296 Hz. Males gave strong responses to neighbors' songs that had been lowered by about 400 Hz, which is about 11% of the mean midfrequency in field sparrow song. Territorial responses were eliminated when neighbors' songs were lowered by more than about 900 Hz. Thus, there is a fairly narrow range of frequencies within which field sparrow songs can vary while functioning in communication. Ss' responses appear to be constrained by the normal range of song frequency variation within the species, but the range of variability within songs of individuals did not influence the degree of frequency shift required to render neighbors' songs unfamiliar.     

Hugs or shrugs: Parental and peer influence on continuity of involvement in sport by female adolescents

The study was designed to examine the influence of significant others (mothers, fathers, and male and female peers) on continuing involvement in sport by adolescent females. Survey data were collected from 376 girls using a forced-choice, self-administered questionnaire. Maintenance of involvement was measured by the proportion of possible years in which the respondents were involved in physical activity within each of three participation contexts (intramural, interschool, and community sport). Several indicators of significant other influence were used. The degree to which involvement in physical activity is maintained is positively related to the source, amount and type of influence received from significant others, and varied by the participation context. Overall, the socializing influence of significant others was able to account for 11% of the variance in intramural activity, 20% of the variance in interschool sport, and 10% of the variance in community-based activity.This study was funded by a grant from Fitness Canada.     

The division of labor within the home: Have gender roles changed?

The purpose of this paper was to examine more recent time-use data regarding the division of labor in the home and compare those findings with that of previously reported data. A 1981 national sample of married Canadian men and women's time use was examined. Generalized least squares regression was employed to examine and predict time use by married men and women as a function of spouse's labor force status, number of children, age of youngest child, and day of the week data were collected. As compared to previous studies, results indicate that over time married women have reduced the amount of time spent in meal preparation while increasing time spent with children. Men increased the amount of time spent in food preparation and child care, although their participation appeared limited primarily to weekend days and invariant to wife's labor force participation.

     

The written summary in group psychotherapy revisited

This paper addresses the use of the weekly written summary with patients in group psychotherapy. In an effort to stimulate group process and effect cotherapist communication, the authors instituted this group recording in an ongoing psychodynamically oriented mixed adult group. While the utilization of this device did, in fact, stimulate the group process and became an important part of the group's life, the therapists additionally saw significant effects upon their working alliance. These included increased focused dialogue upon group dynamics, more purposeful planning for group interventions, and heightened awareness of the significance of interventions in the group.Ms. Bosman-Clark is formerly Clinical Instructor, Department of Psychiatry, Baylor College of Medicine.     

Errors in the quantification of uncertainty: A product of heuristics or minimal probability knowledge base?

The use of intuitive heuristics (e. g. representativeness and availability) has been put forward as an explanation for peoples' assignment of probabilities (Tversky and Kahneman, 1971). This phenomenon is seen as robust since experts as defined by education (professional psychologisis), despite advanced training in statistics and methodology, rely on the same heuristics as novices (lay people). Both experts and novices, as defined by education, were studied in a series of experiments and further classified as experts and novices according to their probability knowledge base, prior to receiving (or not) a brief (15-minute) training session. Immediately following training, subjects completed a probability test which consisted of ten Tversky and Kahneman (e. g. 1974) problems. The training significantly increased the number of problems correctly solved on the probability test and eliminated the expert/novice education classification. The results of a follow-up test 5 weeks after the experiment indicated that the training group maintained its superior performance. It is proposed that failure to use proper methods of probability assignment may not be due to intrinsic human inference biases or heuristics, but is a result of a minimal probability knowledge base.     

Automation of learning-set testing: The video-task paradigm

Researchers interested in studying discrimination learning in primates have typically utilized variations in the Wisconsin General Test Apparatus (WGTA). In the present experiment, a new testing apparatus for the study of primate learning is proposed. In the video-task paradigm, rhesus monkeys (Macaca mulatta) respond to computer-generated stimuli by manipulating a joystick. Using this apparatus, discrimination learning-set data for 2 monkeys were obtained. Performance on Trial 2 exceeded 80% within 200 discrimination learning problems. These data illustrate the utility of the video-task paradigm in comparative research. Additionally, the efficient learning and rich data that were characteristic of this study suggest several advantages of the present testing paradigm over traditional WGTA testing.