No evidence for accurate visuomotor memory: systematic and variable error in memory-guided reaching

The authors explored whether the motor system has access to highly accurate information about the aiming environment after visual occlusion. Participants (N = 14) reached to 1 of 3 midsagittal targets in 4 visual conditions (open-loop, brief-delay, 500-ms delay, and 2,000-ms delay). In all conditions, the aiming environment was first viewed for 2,000 ms. Movements were cued immediately after the initial viewing period in the open-loop and brief-delay conditions. Vision was not occluded until movement onset in the open-loop condition, whereas vision was occluded coincidentally with the movement cue in the brief-delay condition. In the 2 longer delay conditions, the movement was cued following a 500- or a 2,000-ms no-vision delay period. Participants overshot the target in the open-loop condition, but that tendency was significantly reduced in the 3 delay conditions. Moreover, endpoint variability was greater in the 3 delay conditions than in the open-loop condition. A speed-accuracy tradeoff account could not explain the differences between open-loop and delayed reaching. Those findings suggest that the motor system does not have access to highly accurate information about the aiming environment for any appreciable period of time following visual occlusion, consistent with the view that the visuomotor system operates in real time.     

Pre-training prevents context fear conditioning deficits produced by hippocampal NMDA receptor blockade

These experiments explore parallels between the neurobiological substrates of spatial and context learning. Male Long-Evans rats were employed in a context fear conditioning protocol that involved sequential acquisition and testing in two distinct contexts. Rats received three unsignaled footshocks in one context and were tested for context fear, measured as freezing, the next day. Four days later, the procedure was repeated in a different, distinct context. Rats received a hippocampal infusion of either the NMDA receptor antagonist 5-amino-phosphonovaleric acid (APV, 10 microg) or vehicle prior to training in each context. NMDA receptor blockade was effective in impairing context learning only in the first context. Context fear acquisition was not impaired by APV in the second context, indicating that pre-training (in the first context) mitigated the effects of APV. These data agree with those seen previously in the water maze, where pre-training prevented learning deficits produced by NMDA receptor blockade. The data thus suggest that the neurobiological substrates of context learning and place learning overlap.     

Demonstrating a wordlikeness effect on nonword repetition performance in a conduction aphasic patient

The purpose of this study was to identify the nature of the deficit for a conduction aphasic patient in order to evaluate two different theories of conduction aphasia. First, a conduction aphasic patient FS was tested on auditory word-pair discrimination, word-repetition, and picture-naming. The results of these tasks indicated that her deficit was likely to be post-lexical rather than perceptual or lexical. Next, we examined her repetition performance for two types of nonwords (high-wordlike and low-wordlike nonwords) to distinguish the two theories. FS exhibited a wordlikeness effect: she produced more correct moras and more correct combinations of moras for high-wordlike nonwords than low-wordlike nonwords. We conclude that she had difficulty in maintaining stable phonological representations of verbal materials in the output buffer.     

Masked priming of words and nonwords in a naming task: Further evidence for a nonlexical basis for priming

Masked priming effects in word identification tasks such as lexical decision and word naming have been attributed to a lexical mechanism whereby the masked prime opens a lexical entry corresponding to the target word. Two experiments are reported in which masked repetition priming effects of similar magnitude were obtained with word and nonword targets in a naming task. Masked orthographic priming was more stable for word than for nonword targets, although morphological primes produced no advantage beyond that achieved by matched orthographic primes. These results, taken together with the recent finding that repetition priming of nonwords can be obtained in the lexical decision task, support the view that masked priming of words and nonwords has a nonlexical component. We suggest that masked primes can enhance target identification by contributing to the construction of an orthographic or a phonological representation of the target, regardless of the target's lexical status.     

Subadditivity in Memory for Personal Events

Abstract—People's subjective probability judgments of external events are often subadditive (i.e., the probability estimates of component parts of a single event sum to greater than one)—a clear violation of the extensional nature of probability theory. We show that people's frequency judgments of personal events can also be subadditive. We found subadditivity even when component events made up a proper subset of a wider composite event. Our findings imply that the somewhat arbitrary choice of the specificity with which questions are asked can produce widely different reports for the same composite events.     

Gender,Race, and Performance Expectations of College Students

Women often have low performance expectations for themselves but expect other women to succeed. We found minority students think not only that they will do worse than other minority group members, but also that their group will do poorly. Low individual and group success expectations make the results for minorities doubly troubling.     

Substance Use and Psychological Adjustment in Homeless Adolescents: A Test of Three Models

Three models of adolescent substance use, the deviance-prone, affect-regulation, and normative development models, were assessed regarding their ability to predict the substance use of a high-risk homeless adolescent sample with high rates of deviance, depression, and substance use. Hierarchical multiple regression analyses that included tests for curvilinear and gender interaction effects were performed. Results supported the deviance-prone model most strongly, with delinquency but not aggressive behavior predicting substance use. The affect-regulation model received support for females but not for males. With respect to the normative development model, results did not indicate that moderate substance users were better off than abstainers in terms of negative affect or interpersonal relationships.     

Spatial and relational frameworks for free recall in young and older adults

Previous studies have demonstrated that older adults can use visually distinctive cues to enhance their spatial memory performance and their recall of the identities of items located in space. Other research has shown that older adults can also use relational information to enhance recall. The relationship between relational and visuospatial support for memory across the adult lifespan is complex and has been little explored. In the present study, this relationship was examined in tasks that measured free recall for item sets possessing different degrees of visuospatial and relational support for recall. It was predicted that both types of support would enhance older adult recall relative to that of the young, and that the two types of support would synergize. The results were generally consistent with these predictions. These findings show that older adults can use relatively simple relational or visuospatial support systems to enhance free recall significantly. This research was supported by Grant AGI 1605, National Institute on Aging.     

Generative Concern, Political Commitment, and Charitable Actions

The implications of psychosocial generativity (Erikson, 1950) for understanding contemporary politics were explored. Study 1 replicated, in two samples, previous findings that generativity concerns are related to a variety of political activities, including the expenditure of time and money in support of political organizations. Using path analyses, Study 2 extended these findings and demonstrated how midlife generativity concerns interacted with political orientation and interest in politics to produce stronger relationships with giving. These findings suggest that people view the political arena as one important way to improve society and thereby manifest cultural generativity. Although focusing on the domain of politics, these studies highlight the complexity of generativity as a construct; broad concerns with generativity operate within the context of ideological commitments to produce greater levels of generative activity.     

Evaluating a more cost-efficient alternative to providing in-home feedback to parents: the use of spousal feedback.

We evaluated the contribution of spousal feedback to a parent education curriculum designed for parents of children with autism. A modified multiple baseline design across 3 husband-and-wife dyads was used to examine the effects of teaching parents to give each other feedback on their teaching performance. For 5 of 6 participants, improvement in teaching performance occurred following didactic presentations. However, additional improvement was observed for 5 participants when the spousal feedback component was implemented.