Spatial and visual learning deficits in Alzheimer's and Parkinson's disease

Experimental paradigms adopted from animal models were used to compare the neuropsychological mechanisms underlying the dementias of Alzheimer's and Parkinson's diseases. Two tasks were selected because characteristic profiles of impairment in nonhuman primates are seen following selective lesions of frontal cortex, temporal cortex, and fornix. The tasks consisted of a spatial and a visual learning problem, each with two components: (1) original learning and (2) reversal of the original learning. The Alzheimer's patients were significantly impaired on original learning and reversal learning in the visual modality compared with demented Parkinson's patients, even though both groups were equated for severity of dementia. On the spatial tasks, both the Alzheimer's and the demented Parkinson's patients were impaired on reversal learning but not on original learning. The profile of deficits on the visual tasks may serve to differentiate Alzheimer's from Parkinson's dementia and may reflect selective orbitofrontal system lesions in the former.     

A demonstration of the costs and benefits of expertise in recognition memory

In their area of expertise experts know more potentially interfering facts than nonexperts do, yet their memory IS superior to that of nonexperts. This has been termed the “paradox of interference.” We proposed that the ability of experts to go beyond the information given allows them to infer the presence of items that might not otherwise be remembered. However, such inferences can also be detrimental to accurate recognition memory in that such inferences might become confused with actual targets. We examined the benefits and costs of expertise in two recognition memory experiments In which experts and nonexperts participated. Experts in Ex-penment 1 were knowledgeable about baseball; those in Experiment 2 were knowledgeable about Ohio geography. Distractors in both studies bore a synonymous, an inferential, or no special relation to the targets. In the last instance, experts had recognition memory superior to that of the nonexperts. When the distractors were related to the targets, however, the non-experts were superior. We proposed that experts' inferential behavior is a contributor to their generally superior memory, but that task demands can convert this asset into a liability.     

The Belief in Good Luck Scale

The construction and properties of the Belief in Good Luck (BIGL) Scale are described. Three studies provide evidence that reliable individual differences exist with respect to beliefs about luck. Some individuals maintain an irrational view of luck as a somewhat stable force that tends to influence events in their own favor, while others seem to hold the more rational belief that luck is random and unreliable. Further, these beliefs showed a considerable amount of stability over time. The BIGL was significantly related to locus of control (primarily to a chance subscale), but other evidence suggested these constructs were distinct. Belief in good luck was not related to general optimism, academic pessimism, self-esteem, desire for control, or achievement motivation. There was also evidence that belief in good luck was distinct from feeling fortunate or generally satisfied with one's life. Ethnic group differences were observed for the BIGL scale, showing that Asian-Americans were more likely to endorse superstitious beliefs about luck than non-Asians. Finally, the BIGL scale was shown to predict positive expectations for the outcome of everyday situations that are typically associated with luck. This is generally in agreement with previous findings suggesting that people who believe in personal good luck react to lucky events by becoming more positive about the likelihood of future success (Darke & Freedman, 1997). In general, it is suggested that irrational beliefs about luck can serve as a source of positive expectations for the outcome of future events.     

Children's capacity to agree to psychological research: knowledge of risks and benefits and voluntariness

A series of studies investigated the capacity of children between the ages of 7 and 12 to give free and informed consent to participation in psychological research. Children were reasonably accurate in describing the purpose of studies, but many did not understand the possible benefits or especially the possible risks of participating. In several studies children's consent was not affected by the knowledge that their parents had given their permission or by the parents saying that they would not be upset if the children refused. In contrast, other studies found that children were much more likely to stop their participation if the experimenter said explicitly that she would not be upset if they stopped. We suggest that experimenters should pay more attention to describing the possible risks and benefits of participation in research, and that they should also make it clearer to children that they are free to stop once they have begun.     

Illusions of Safety in a Risky World: A Study of College Students' Condom Use

The role that costs, benefits, and perceptions of invulnerability play in condom use was examined in a sample of students ( N = 211) at 4-year and 2-year colleges. In multiple regression analyses, past condom use was related to relative invulnerability, low present risk, and inexperience. Less intended condom use was associated with high perceptions of relative invulnerability and low perceptions of present risk. It appears that many college students feel protected from HIV because they judge their current sexual environment to be safe due to monogamy, sexual history taking, and the ability to tell a partner's HIV status. Independent of that, feelings of relative invulnerability are associated with more condom use—perhaps an accurate judgment of past risky behavior.     

The effects of situational performance constraints on intrinsic motivation and satisfaction: The role of perceived competence and self-determination

Situational performance constraints, task interest, and pay contingencies were manipulated in a laboratory study in order to investigate the cognitive mechanisms associated with the previously observed detrimental effects of constraints on affective task reactions. It was hypothesized that feelings of task competence and self-determination would account for both the direct and the interactive effects of constraints on motivation and satisfaction. The results of the study indicated that despite the fact that participants' performance was being constrained and they were aware of these constraints, the mere presence of the constraints alone failed to result in lower levels of satisfaction or motivation on a proofreading task. Post hoc analyses suggested that the constraints, in fact, led to negative affective task reactions when they also reduced participants' feelings of competence and self-determination. Interestingly, participants' generalized locus of control was associated with such effects. Internals tended to maintain stronger feelings of competence and self-determination than externals in the presence of constraints, thereby also maintaining greater motivation and satisfaction.     

Perceptions of helpfulness and behavior in groups

Before, midway, and late in a 50-hour small group experience, 28 persons separately and subjectively appraised the helpfulness of 60 items representing Yalom's (1975) 12 curative factors of group psychotherapy. Items from the catharsis and interpersonal learning factors proved highly and increasingly helpful, despite their poor internal consistency. Item helpfulness also linked to members' ingroup behavior, as measured by peer ratings of acceptance-rejection of self and others. (Hurley, 1976). Persons more accepting of self and others regarded family reenactment items as more helpful, and advice and guidance items as less helpful, than did members who were more rejecting of self and others.     

On the role of reduced auditory feedback and kinesic self-stimulation during Stroop Color-Word performance1

Feedback from one's own voice provides important vocal–motor cues for effective cognitive processing. Reduction of such feedback is known to disturb such functioning. Work in our laboratory has shown that kinesic self-stimulation also plays an important role in cognition, and appears to regulate the focusing of attention under conditions of distraction. The present study investigated the effects of both auditory feedback and kinesic self-stimulation in the regulation of cognitive interference during performance of the Stroop Color-Word Task. Twelve subjects were tested on the Stroop task under conditions of normal and occluded hearing. Kinesic self-stimulation and response errors during color-word performance were recorded on video tape. The findings indicated that not only did self-stimulation increase when voice feedback was reduced, but that this increase was associated with a reduction in specific types of color-word performance errors. Individual differences revealed that high kinesic responders made significantly fewer errors in task performance than did low kinesic responders. Results were interpreted as revealing a kinesic feedback mechanism which has adaptive significance in regard to self-editing when auditory feedback is reduced.     

On the statistics of vision: The Julesz conjecture

This paper describes a class of random patterns which have the same first-, second-, and third-order statistics as coin tossing, but are visually different. The patterns are counterexamples to a conjecture of Julesz that all the eye can discriminate is first- and second-order statistics.     

Selective delayed alternation deficits in dominantly inherited olivopontocerebellar atrophy

In order to characterize more completely the nature of the frontal lobe-type cognitive changes in patients with dominantly inherited olivopontocerebellar atrophy (OPCA) we administered two tasks sensitive to frontal system dysfunction, delayed alternation (DA) and delayed response (DR), to 12 patients from one OPCA family. Affected members from this family have previously been shown to have a marked and widespread cerebral (including frontal) cortical cholinergic reduction as severe as that observed in Alzheimer's disease. Performance on DA, but not on DR, was significantly impaired in the OPCA patients compared to that in the controls. We suggest that the DA deficits in OPCA could be a consequence of a loss of cholinergic innervation to orbitofrontal or possibly temporal cortical areas and/or damage to the integrity of the cerebello-frontal neuronal connections.