DOUBLE DISSOCIATION BETWEEN MEMORY SYSTEMS UNDERLYING EXPLICIT AND IMPLICIT MEMORY IN THE HUMAN BRAIN

Abstract— Amnesic patients have impaired explicit memory that is evident in poor recall and recognition of words, yet can have intact implicit memory for words as measured by repetition priming, the enhanced efficiency for reprocessing those word's. The dissociation between explicit and implicit memory for words is a fundamental characteristic of normal cognition that could reflect two different functional architectures of the human brain two separate processing systems or two levels of operation of a single system with implicit memory less demanding of that system. We present a patient who has a lesion in the right occipital lobe and who showed intact explicit and impaired implicit memory for words. The deficit was specific to visual priming. The double dissociation between explicit and implicit visual memory for words indicates that separate processing systems mediate these two forms of memory, and that a memory system in right occipital cortex mediates implicit visual memory for words.     

Client and counsellor narrative accounts of congruence during the most helpful and hindering events of an initial counselling session

The role of congruence in establishing and maintaining a therapeutic alliance has been emphasized by theorists within the humanistic/person‐centred tradition. However, there appears to be a lack of research that explores the processes occurring during moments of congruence or incongruence. The main objective of the present study was to gather qualitative data about congruence based on both participants’ narrative accounts of their subjective reactions during the most helpful and the most hindering event of an initial counselling session. Client and counsellor recollections of their experiences during these two events were stimulated through the replay of a video‐tape after the session. The event identification came from the client through a Brief Structured Recall interview. During the hindering event, both participants were incongruent. There was a mismatch between what they were feeling and what they were expressing verbally and/or non‐verbally. At the same time the client was feeling criticised and offended by counsellor's confrontation. By contrast, during the helpful event both participants were congruent. The counsellor was experiencing empathic understanding toward his client and the client was feeling accepted and understood. The implication of these findings are discussed in terms of how congruence might affect the construction of significant events during the therapeutic hour.     

How learning contexts facilitate strategy transfer

The present study assessed the role of context in the acquisition and transfer of a mathematical strategy. One hundred and six children were assigned to four conditions: direct strategy instruction, guided discovery, direct teaching plus discovery, or a control condition. The intervention consisted of fourteen sessions during which the number-family strategy, useful for addition and subtraction, was taught. Third grade students in the guided discovery condition performed better than those in the direct instruction condition on far transfer problems that measured deep conceptual understanding. Students who had total or partial exposure to guided discovery held stronger beliefs and adopted more positive goals about the importance of mathematical understanding and peer collaboration, attributed less importance to task extrinsic reasons for success, and reported greater use of deep processing strategies than students exposed to direct, explicit instructions. Finally, students in the discovery conditions were able to communicate more effectively during problem solving than students in the direct instructions condition.     

An investigation of the relationship between self-efficacy and the communication effectiveness of product manual formats

Product manuals have been virtually ignored in published research despite their relevance to consumer satisfaction and marketplace safety. This study examines self-efficacy (perceptions of capabilities related to operating a product) and how it influences the effectiveness of and is also influenced by three safety message formats commonly used in product manuals (i.e., 1. safety messages presented in list format at the front of the manual; 2; safety messages presented by semantic similarity interspersed throughout the manual—chunked format, and 3. safety messages presented in a combined format—both list and chunked). As anticipated, pre-exposure self-efficacy was a significant covariate which was found to be positively related to post-exposure self-efficacy and negatively related to information evaluation. Further, controlling for pre-exposure self-efficacy, post-exposure self-efficacy was significantly lower in the combined (list plus chunked) condition. Findings of this research have important implications for the practice of repeating safety warnings and future research in the consumer information domain.Authors are listed in alphabetical order. This study was supported by an Illinois State University Research Grant.     

The effects of room management and small-group procedures on the behavior of older adults who have Alzheimer's disease

The effects of room management and small groups procedures on the behavior of five older adults with Alzheimer's Disease was experimentally evaluated by a multielement design with replications across five subjects. Engagement during both room management and small groups was higher than during no treatment baselines. The effects on affective and maladaptive behaviors were of small magnitude. Evidence of individual differences was found both with respect to absolute proportions of time spent in various behaviors and with respect to interactions between individual differences and experimental conditions.     

Functional Aspects of Recollective Experience in Face Recognition

This article describes two experiments on awareness in recognition memory for novel faces. Two kinds of awareness, recollective experience and feelings of familiarity in the absence of recollective experience, were measured by "remember" and "know" responses. Experiment 1 showed that "remember" but not "know" responses were reduced by divided attention at study. Experiment 2 showed that massed versus spaced repetition of faces in the study list had the opposite effects on "remember" and "know" responses. Massed repetition increased "know" responses and reduced "remember" responses. Spaced repetition increased "remember" responses and reduced "know" responses. The results of both experiments replicate previous findings from the verbal domain in the domain of face recognition, and hence they increase the ecological validity of this experiential approach to memory and awareness and the generality of its database. These findings are discussed from a rehearsal perspective on factors influencing the two states of awareness and in relation to the alternative "process dissociation" procedure.     

Quantitative measurement of observed workload in the analysis of aircrew performance

A methodology for the quantitative evaluation of observed workload was proposed. The model was designed to provide point estimations of observed workload at any time during the performance of a set of tasks. The model was also designed to provide information about the task-scheduling strategies used to complete a set of tasks. The proposed model was then tested with data from a full mission flight simulation. The model predictions correlated significantly with expert ratings of workload management made during the flight simulation. The model was also able to distinguish between low- and high-performing aircrews when performance was based on the number of errors made during flight simulations.     

Active control in interrupted dynamic spatial orientation: The detection of orientation change

Gibson (1966, 1979) suggested that an important property of perception is that the observer is active. Two experiments were conducted to examine the benefits of active observation in determining dynamic spatial orientation. Subjects were presented with displays simulating locomotion through a three-dimensional environment. Active observers continuously controlled locomotion, whereas passive observers viewed the display. During the trial, the display was blacked out for a brief period, followed by a static image that was at either the correct or the incorrect orientation following the blackout. Subjects were required to indicate whether they were positioned at the correct extrapolated orientation. The presence or absence of orientation change, the type of change (changes in rotation about the depth axis [roll], horizontal axis [pitch], or forward translation), the duration of the blackout, and the consistency of change were varied. In addition, the experiments used either a compensatory or a pursuit tracking task. Active observers had greater sensitivity than did passive observers in detecting a change for both tracking tasks. Subjects in both experiments exhibited greater sensitivity in detecting inconsistent changes (relative to consistent changes), suggesting that the dynamics specified by optical flow were incorporated in extrapolated orientation. In addition, sensitivity decreased with an increase in blackout duration. The results are discussed in terms of an extrapolation model of perception that incorporates the responses executed by active observers.     

Target and nontarget grouping in visual search

Results recently reported by Driver, McLeod, and Dienes (1992) are used to contrast three accounts of visual search—in particular, their mechanism for easy conjunction search. In the Driver et al. study, the target was defined by a conjunction of form and movement; the key manipulation was phase in both target and nontarget motion sets. Mechanisms working separately on each display element (inhibition from nontarget features, facilitation from target features) are unable to explain large effects of phase, since this is defined only by relationships between one element and another. As implemented in the guided search model of Cave and Wolfe (1990), local suppression between similar elements is also unable to account for the results. More promising is an approach based on perceptual grouping: Elements moving in phase can be selected (target motion) or rejected (nontarget motion) as a group. Rather than a bias against elements that are similar to or grouped with their neighbors, there is a bias to treat grouped elements together.     

A pointing technique for rapidly collecting localization responses in auditory research

A technique is described for rapidly collecting responses in auditory-localization experiments. Subjects indicate the perceived direction of the sound by pointing at a 20-cm-diam spherical model. In Experiment 1, the subjects judged the direction of a broadband signal, which could originate from any of 239 directions ranging through 360° of azimuth and between ?45° and +90° of elevation. Using this technique, the subjects responded 2–8 times more rapidly than previous subjects who used either a verbal-reporting technique or a head-pointing technique. Localization judgments were as accurate as they had been with verbal reports, but were not as accurate as judgments collected using the head-pointing technique. In Experiment 2, the signal was turned off and the experimenter read the spherical coordinates of the signal location to the subjects. The subjects pointed to these coordinates more accurately than they had judged the direction of the sounds in Experiment 1, suggesting that the response technique had not been the limiting factor in that experiment. Circumstances relevant to the choice of response techniques for auditory-localization experiments are discussed.