Selective spatial attention and length representation in normal subjects and in patients with unilateral spatial neglect

The aim of this study was to assess whether perceptual representation along the horizontal axis is affected by hemispace position of the stimulus or by orienting attention to one side. Ten control subjects and 10 right brain damaged patients with left unilateral spatial neglect (USN) were asked to bisect lines of five lengths in three space positions (left, center, right) and under three cueing conditions (no cue, left cue, right cue). Normal controls showed significant displacement of bisection opposite to the side of hemispace presentation and toward the side of cueing. USN patients showed a bisection error toward the right end which increased with lines placed in the left hemispace and decreased with lines placed in the right hemispace and when attention was oriented toward the left side. We conclude that (1) In absence of cues normal subjects tend to overestimate the portions of space closer to their body midline; (2) both normal and USN patients tend to overestimate portions of space that they direct their attention to; (3) USN patients' performance without cueing is consistent with an attentional shift toward the right hemispace implying a gradient of overestimation of the right-most portions of space. A common neural substratum for directing attention and space representation can explain these findings.     

Psychic phenomena following near-death experiences: An Australian study

This study examines the incidence of reports of psychic phenomena and associated beliefs both before and after the near-death experience (NDE). The near-death experiencers interviewed reported no more psychic phenomena before the NDE than the general population. There was a statistically significant increase following the NDE in the incidence of 14 of 15 items examined.     

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.     

Effect of backward priming on word recognition in single-word and sentence contexts

Backward priming was investigated under conditions similar to those used in lexical ambiguity research. Subjects received prime-target word pairs that were associated either unidirectionally (BABY-STORK) or bidirectionally (BABY-CRY). In the first experiment, targets were presented 500 ms following the onset of visual primes, and subjects made naming or lexical decision responses to the targets. Forward priming was obtained in all conditions, while backward priming (i.e., priming for pairs in which there was a unidirectional target-to-prime association, as in BABY-STORK) occurred only with lexical decision. In the second experiment, primes were presented auditorily, either in isolation or in a sentence. Targets followed the offset of the primes either immediately or after 200 ms. Backward priming occurred with both response tasks, but only when the prime was an isolated word. In addition, backward priming decreased over time with the naming task, but not with lexical decision. These results suggest that the locus of the backward priming effect is different for the two response tasks. Further, the lack of a backward priming effect with sentence contexts suggests that backward priming cannot account for the demonstrations of multiple access in the lexical ambiguity literature. These results, therefore, support a context-independent view of lexical access.     

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.     

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.