Response to commentaries on “A neurobiological model for near-death experiences”

This work has received financial support from FONDECYT (Project 1111-88). The authors also acknowledge the helpful comments of Dr. Bruce Cassels.     

Insight without awareness: On the interaction of verbalization, instruction and practice in a simulated process control task

Four experiments in which subjects learned to control two versions of a complex simulated process control task show that verbalizable knowledge of procedures used to perform these tasks is very limited and is acquired late in learning. Individual learning curves associated with these tasks showed sudden improvements in performance, which were not accompanied by a similar increase in verbalizable knowledge. It was also found that verbal instructions consisting of exemplar memorization, strategies for rule induction, simple heuristics, and experts' instructions were all effective in enhancing novice subjects' performance. A theoretical framework is proposed in which subjects draw on two separate but interacting knowledge structures to perform these tasks. One knowledge structure is based on memory for past experiences (close analogies), and the other is based on one's current mental model of the task. Implicit sets of competing rules that control response selection are derived from both sources of knowledge. It is suggested that dissociations between task performance and verbalizing occur because memory-based processing tends to have more control over response selection because of its greater specificity, whereas a mental model tends to be the preferred mode for verbal reporting because of its greater accessibility.     

Base-rate effects in category learning: a comparison of parallel network and memory storage-retrieval models

Exemplar-memory and adaptive network models were compared in application to category learning data, with special attention to base rate effects on learning and transfer performance. Subjects classified symptom charts of hypothetical patients into disease categories, with informative feedback on learning trials and with the feedback either given or withheld on test trials that followed each fourth of the learning series. The network model proved notably accurate and uniformly superior to the exemplar model in accounting for the detailed course of learning; both the parallel, interactive aspect of the network model and its particular learning algorithm contribute to this superiority. During learning, subjects' performance reflected both category base rates and feature (symptom) probabilities in a nearly optimal manner, a result predicted by both models, though more accurately by the network model. However, under some test conditions, the data showed substantial base-rate neglect, in agreement with Gluck and Bower (1988b).     

Parts of visual objects: an experimental test of the minima rule

Three experiments were conducted to test Hoffman and Richards's (1984) hypothesis that, for purposes of visual recognition, the human visual system divides three-dimensional shapes into parts at negative minima of curvature. In the first two experiments, subjects observed a simulated object (surface of revolution) rotating about a vertical axis, followed by a display of four alternative parts. They were asked to select a part that was from the object. Two of the four parts were divided at negative minima of curvature and two at positive maxima. When both a minima part and a maxima part from the object were presented on each trial (experiment 1), most of the correct responses were minima parts (101 versus 55). When only one part from the object--either a minima part or a maxima part--was shown on each trial (experiment 2), accuracy on trials with correct minima parts and correct maxima parts did not differ significantly. However, some subjects indicated that they reversed figure and ground, thereby changing maxima parts into minima parts. In experiment 3, subjects marked apparent part boundaries. 81% of these marks indicated minima parts, 10% of the marks indicated maxima parts, and 9% of the marks were at other positions. These results provide converging evidence, from two different methods, which supports Hoffman and Richard's minima rule.     

Social and life skill competence in potential early school-leavers

Competencies in social and life skills of a group of students expecting to leave school at the end of Grade 10 in Australia is compared with groups expecting to continue. Academic performance and skills were also assessed. The results of the study indicated that the potential early school-leavers were disadvantaged both socio-economically and academically. But, surprisingly, the findings indicated that they were not significantly different from the other two groups of students targeted in the study in terms of their social and life skills. The results imply that potential early leavers in school populations may be unnecessarily disadvantaged because school programmes, in concentrating on a narrow range of cognitive skills, do not build on personal competency skills already possessed by students of all levels of ability. Whilst this is the case, potential early school-leavers will be likely to continue to be disaffected and disadvantaged educationally.     

Admissions interviews at university as counselling tools

Little research has been conducted on the university admissions interview, and with increasing selection ratios there has been a tendency for universities to dispense with interviews altogether. This paper argues for a re-assertion of the interview as a valuable component of the admissions procedure, not necessarily to improve institutional decision-making but for the guidance and personal decision-making of candidates. The rationale for treating admissions interviews as opportunities for counselling are reviewed, and the advantages for both candidates and institutions are outlined.     

Developmental and individual differences in preschoolers' recognition memories: The influences of gender schematization and verbal labeling of information

Eighty-three 37-92-month-old children's gender schematization and recognition memories for gender-typed content were assessed. Verbal labeling of stimuli and age were positively associated with children's memories. Highly gender schematic children displayed better memories for gender-role consistent information and committed more gender transformation errors than less gender schematic children. Interactions between children's gender schematization, age, and labeling condition were observed. Labeling of stimuli facilitated less schematic children's memories for gender-role consistent information. Gender schematization was positively associated with younger children's memories, suggesting younger children's memories are more strongly mediated by gender schematization than older children's. Results support the position that studies of gender schema development require an integrated approach recognizing individual and developmental differences in gender schematic processing.Completion of this project was facilitated by funds received while the author was a National Institute of Mental Health Postdoctoral Fellow at the University of Denver: Grant 5T32 MH 15780-09. This support is gratefully acknowledged. An earlier version of this paper was presented at the Conference on Human Development, Charleston, South Carolina, 1988. The author would like to thank the faculty and staff of the Tiny Tot, Jack & Jill, Little Learners II, Plymouth and Upstate preschools for their assistance and cooperation. The author wishes to recognize James Aber, Rosanne David, Melisa Shack, and Susan Zigelbaum for their exceptional service in conducting the project; and would also like to thank Joan Barth, D. Bruce Carter, Gail S. Goodman, Carol L. Martin, William J. Meyer, Kathy Park, Ralph J. Roberts, Jaipaul L. Roopnarine, Margaret L. Signorella, and the anonymous reviewers for their comments and suggestions on earlier drafts of this article.