Brain stem evoked response suppression during speech production

Auditory brain stem evoked responses (BSERs) to repetitive clicks were recorded in subjects engaged in overt speech, whispering, silent articulation, and covert verbal rehearsal tasks and during a control condition of attending to the clicks. Overt speech and whispering resulted in a significant amplitude reduction of the fifth peak of BSERs without affecting the amplitudes or the latencies of the earlier peaks. These data strongly suggest efferent inhibition of irrelevant auditory input at the level of the upper brain stem.     

Coping in Families with a Retarded Child

The impact of a retarded child on a family has previously been described by individual family members' reports. This study of 40 families, 10 in each of four critical periods during the life of the retarded child, utilized videotaped interviews with whole families, with subsequent clinical observation and analysis based on the Beavers family assessment model. Healthy and problematic adaptations are delineated, with specific attention to systems concepts such as family structure and power, member individuation, feeling expression, and values. The report includes data analysis and a summary of pattern differences in family functioning.     

A new empirical angle on the variability debate: quantitative neurosyntactic analyses of a large data set from Broca's aphasia

Behavioral variation in Broca's aphasia has been characterized as boundless, calling into question the validity of the syndrome-based schema and related diagnostic methods of acquired language disorders. More generally, this putative variability has cast serious doubts on the feasibility of localizing linguistic operations in cortex. We present a new approach to the quantitative analysis of deficient linguistic performance, and apply it to a large data set, constructed from the published literature: Comprehension data of 69 carefully selected Broca's aphasic patients, tested on nearly 6000 stimulus sentences, were partitioned in different ways, and subjected to a series of analyses. While a certain amount of variability is indeed evident in the data, our quantitative analyses reveal a highly robust selective impairment pattern for the group: the patients' ability to analyze syntactic movement is severely compromised, in line with the Trace-Deletion Hypothesis. Further analyses suggest that patients' performance on no-movement sentence types exhibits less variation than on sentences that contain movement. We discuss the clinical and theoretical implications of our results.     

Mechanism of age-related differences in frequency discrimination with backward masking: speed of processing or stimulus persistence?

In Experiment 1, frequency-discrimination thresholds were estimated in a 2-interval, forced-choice, backward masking procedure with a masker acoustically dissimilar to the targets. Young subjects were more efficient in escaping the effects of masking than were their elderly counterparts. In Experiment 2, young and elderly subjects performed the same task, with a masker acoustically similar to the targets and with a target-dissimilar masker. Under target-similar masking and at short target-masker intervals, the elderly demonstrated significant improvement, reaching the level of performance of the young, whereas under the target-dissimilar masker, the age-related differences were restored. Both age-related slowing of information processing and increase in stimulus persistence can account for the results of Experiment 1, but only increased stimulus persistence explains the results of Experiment 2.     

On the Positive Side of Avoidance Motivation: An Increase in Avoidance Motivation Reduces Procrastination among Students

People who procrastinate often pay a heavy price in terms of illness, stress, and poor performance. Because procrastination has harmful consequences, we predicted that avoidance motivation, a self‐regulation system that protects people from harm, would also protect them against procrastination. We hypothesised that avoidance motivation reduces procrastination, despite the known destructive effects avoidance motivation has on thriving. In Study 1, students high in chronic‐avoidance motivation had the lowest dropout rates from a bonus‐granting longitudinal study. In Study 2, avoidance motivation was negatively related to delay in submitting a term paper, when controlling for chronic procrastination, self‐efficacy, impulsiveness, and age. In Study 3, an experimental manipulation of avoidance motivation reduced procrastination three times, but only once significantly. In Study 4, manipulations of both avoidance motivation and approach motivation, relative to a control motivation, using a within‐subjects design, indicated that the avoidance manipulation reduced procrastination in submitting subsequent reading reports, whereas the approach manipulation did not. We subjected all our results to a meta‐analysis that indicated that avoidance motivation had a significant preventive effect on procrastination. We conclude that avoidance motivation can reduce procrastination, and suggest that our avoidance‐manipulation techniques could be applied across a variety of organisational and educational settings.     

Age-related differences in acquisition of perceptual-motor skills: working memory as a mediator

Aging is associated with reduced performance on information processing speed, memory, and executive functions tasks. Although older adults are also less apt in acquiring new perceptual-motor skills, it is unclear whether and how skill acquisition difficulties are associated with age-related general cognitive differences. We addressed this question by examining structural relations among measures of cognitive resources (working memory) and indices of perceptual-motor skill acquisition (pursuit rotor and mirror tracing) in 96 healthy adults aged 19-80 years of age. Three competing structural models were tested: a single (common) factor model, a dual correlated factors model, and a hierarchical dual-factor model. The third model provided the best fit to the data, indicating age differences in simple perceptual-motor skill are partially mediated by more complex abilities.     

The Cognitive Underpinnings of Continuous Identity: Higher Episodic Memory Recall and Lower Heuristic Usage Predicts Highest Levels of Self-Continuity

Continuous identity (CI) is a sense of persistent identity wherein the present self is seen as overlapping with the past and future selves. This study addressed the hypothesis that judgments of CI require successful retrieval of information by examining the relationship between varying levels of CI and two forms of memory recall. The pattern of findings indicated that high levels of cued memory recall combined with low levels of heuristic usage were associated with higher levels of CI, and this occurred for both past-to-present CI and present-to-future CI. We propose that to achieve high levels of CI, individuals need to access and analyze a fund of stored autobiographical information.     

Age-related differences in the course of cognitive skill acquisition: the role of regional cortical shrinkage and cognitive resources

This study examined the impact of age-related differences in regional cerebral volumes and cognitive resources on acquisition of a cognitive skill. Volumes of brain regions were measured on magnetic resonance images of healthy adults (aged 22-80). At the early stage of learning to solve the Tower of Hanoi puzzle, speed and efficiency were associated with age, prefrontal cortex volume, and working memory. A similar pattern of brain-behavior associations was observed with perseveration measured on the Wisconsin Card Sorting Test. None of the examined structural brain variables were important at the later stages of skill acquisition. When hypertensive participants were excluded, the effect of prefrontal shrinkage on executive aspects of performance was no longer significant, but the effect of working memory remained.