At-entry differences in part-time and full-time employees

Research consistently shows part- and full-time workers to be different on a variety of characteristics such as job satisfaction, organizational commitment and intentions to leave the organization. This study challenges the commonly accepted argument that these differences are due to the different structural conditions of work that are faced by part- and full-time workers. The possibility that these differences are the consequence of at-entry differences in dispositions and orientations to work is tested on a sample of part- and full-time registered nurses who had just begun employment. With one exception the part-and full-time employees were found to be the same on fourteen at-entry characteristics. These results strongly suggest that it is the structural conditions of work that produce the often observed differences found between part- and full-time workers.An earlier version of this paper was presented at the 1991 Midwest Sociological Society Meetings, Des Moines, Iowa, April 11–14. Support for the original data collection came from the Division of Nursing of the Health Resources and Services Administration (R01 NU01050-01A1). Joanne McCloskey is to be thanked for allowing us to use this data set.     

Metacognition and mathematics strategy use

The role of children's metacognitive knowledge in their mathematics strategy use was studied by a longitudinal examination of second graders' effort attributions, metacognition for mathematics, and strategy use while solving mathematics problems. Children's correct use of retrieval, internal and external strategies, and the prevalence of strategy use were assessed in September and the following January. Effort attributions for success and failure were also assessed at both points in time. In January, metacognitive knowledge about mathematics strategies was measured. Second graders possess metacognitive knowledge about mathematics strategies, and this knowledge is correlated most strongly with the tendency to use internal strategies in September and correct internal strategy use in September. Effort attributions measured at both timepoints were significantly related to metacognition. Effort attributions in January also correlated with the tendency to use internal strategies in January. In general, the results are consistent with self-system theories, which posit that metacognition, motivation, and strategy use work together to promote learning.     

Very long-term memories of a salient preschool event

Children who attended either a younger (mean age = 3frac12;years) or an older (mean age = 4frac12; years)preschool classroom were interviewed twice about an emergency school evacuation in response to a fire alarm. All children were able to answer some memory questions 2 weeks after the evacuation occurred, but the memory narratives produced by older preschool children showed a more refined knowledge of the temporal and causal sequence of events. Seven years later, memory of the fire alarm was reassessed. Only those preadolescents who had been in the older preschool group at the time of the alarm showed convincing evidence of long-term memory. The offset of childhood amnesia appears to be influenced by developmental changes in cognitive processing.     

A study of the classification capabilities of neural networks using unsupervised learning: A comparison withK-means clustering

Several neural networks have been proposed in the general literature for pattern recognition and clustering, but little empirical comparison with traditional methods has been done. The results reported here compare neural networks using Kohonen learning with a traditional clustering method (K-means) in an experimental design using simulated data with known cluster solutions. Two types of neural networks were examined, both of which used unsupervised learning to perform the clustering. One used Kohonen learning with a conscience and the other used Kohonen learning without a conscience mechanism. The performance of these nets was examined with respect to changes in the number of attributes, the number of clusters, and the amount of error in the data. Generally, theK-means procedure had fewer points misclassified while the classification accuracy of neural networks worsened as the number of clusters in the data increased from two to five.Acknowledgements: Sara Dickson, Vidya Nair, and Beth Means assisted with the neural network analyses.     

Automated Measurement of Mouse Freezing Behavior and its Use for Quantitative Trait Locus Analysis of Contextual Fear Conditioning in (BALB/cJ × C57BL/6J)F2 Mice

The most commonly measured mouse behavior in fear conditioning tests is freezing. A technical limitation, particularly for genetic studies, is the method of direct observation used for quantifying this response, with the potential for bias or inconsistencies. We report the use of a computerized method based on latency between photobeam interruption measures as a reliable scoring criterion in mice. The different computer measures obtained during contextual fear conditioning tests showed high correlations with hand-scored freezing; r values ranged from 0.87 to 0.94. Previously reported strain differences between C57BL/6J and DBA/2J in context-dependent fear conditioning were also detected by the computer-based system. In addition, the use of computer-scored freezing of 199 (BALB/cJ×C57BL/6J)F₂ mice enabled us to detect a suggestive gender-dependent chromosomal locus for contextual fear conditioning on distal chromosome 8 by QTL analysis. Automation of freeze scoring would significantly increase efficiency and reliability of this learning and memory test.     

An Application of the Theory of Planned Behavior to Exercise Among Older Adults1

One hundred five older adults enrolled in exercise classes were recruited from local YMCAs. Exercise behavior was measured 1, 3, and 9 months after beginning the exercise class. Intentions were not a significant predictor of exercise behavior, probably because of a lack of variance; most people intended to exercise. The direct measures of attitudes, subjective norms, and perceived behavioral control, however, explained 9% of exercise behavior at 1 month. They did not significantly explain behavior at 3 and 9 months. When the indirect measure of subjective norms explained 18% of exercise behavior at 1 month. The indirect measure of perceived behavioral control accounted for 27% of the variance at 1 month and 10% at 3 months.     

"Lost in a shopping mall" -- a breach of professional ethics

The "lost in a shopping mall" study has been cited to support claims that psychotherapists can implant memories of false autobiographical information of childhood trauma in their patients. The mall study originated in 1991 as 5 pilot experiments involving 3 children and 2 adult participants. The University of Washington Human Subjects Committee granted approval for the mall study on August 10, 1992. The preliminary results with the 5 pilot subjects were announced 4 days laters. An analysis of the mall study shows that beyond the external misrepresentions, internal scientific methodological errors cast doubt on the validity of the claims that have been attributed to the mall study within scholarly and legal arenas. The minimal involvement -- or, in some cases, negative impact -- of collegial consultation, acadmic supervision, and peer review throughout the evolution of the mall study are reviewed.