Activity of wrist muscles elicited during imposed or voluntary movements about the elbow joint

To examine the coordination of muscles during multijoint movement, we compared the response of wrist muscles to perturbations about the elbow joint with their activation during a volitional elbow movement. The purpose was to test the following two predictions: (a) Responses can occur in muscles not stretched by the perturbation, as has been reported for other multijoint systems; and (b) the motor pattern in response to a perturbation mimics an opposing volitional motor pattern across the two joints. We recorded the electromyographic (EMG) activity of elbow and wrist muscles as well as the flexion/extension motions at the elbow and wrist joints during individual trials that either involved a response to a torque perturbation that extended the elbow or required volitional elbow flexion. The results of this study confirmed that responses were elicited in the nonstretched wrist muscles when the elbow joint was perturbed. The same motor sequence of elbow and wrist flexors was present for both the volitional and perturbation task (with the forearm supinated), regardless of whether the wrist joint was immobilized or freely moving. The findings suggest that the nervous system relies on the purposeful coupling of elbow and wrist flexors to counter the inertial effects during the unrestricted voluntary movement, even though the coupling does not appear to be purposeful during the perturbation or with the wrist immobilized. The coupling of elbow and wrist flexors, however, was not rigidly fixed, as evidenced by muscle onsets that adapted over repeated perturbation trials and a reversal of the wrist muscle activated (wrist extensor) when the forearm was pronated. Hence, the coupling of muscle activities can be modified quantitatively when not beneficial and can be altered qualitatively with different initial configurations of the arm.     

Predicting the Everyday Life Events of Older Adults

Predicting the everyday life events of people is a relatively unexplored topic, although several major theoretical approaches deal with related issues. The dispositional approach would assign a causal role to personality, while the situational approach would locate causation in the person's environment. Variations on these two extreme themes invoke an interactionist interpretation. Beyond this, a genuinely transactional approach focuses on the enduring person-environment relationship established as people deal with major and everyday life events. This study investigated a wide range of predictors of daily positive, negative, and ill-health events over time in a sample of 206 older adults. Results showed that personality variables played only a minor role in predicting daily events, although an interaction between extraversion and social network size was significant. Background demographic variables and the major stressors of recent conjugal bereavement and physical disability played a role in daily event occurrences. Overall, the strongest degree of predictability of events came from the events themselves: The high degree of event stability over time indicated the value of a genuinely transactional model in understanding the occurrence of everyday events.     

Hopelessness in community-residing aged persons: a viable construct?

Previous work with the Geriatric Hopelessness Scale (GHS; Fry, 1984, 1986) suggests that it may be a useful measure of pessimism for a variety of domains among elderly persons. One hundred seven community-residing aged persons were individually administered the GHS and a variety of personality and cognitive functioning measures in an effort to further refine and validate the GHS. Results suggest very modest internal consistency and a poorly defined factor structure for the GHS, in contrast to earlier findings. Although the GHS failed to differentiate elderly persons by age, it was nonetheless related to self-esteem, depression, self-rated health, internality, morale, and life satisfaction. Taken together, these data indicate that the research and clinical utility of the GHS with community-residing aged persons may be more limited than previously believed.     

Personality assessment of the prelingual, profoundly deaf child or adolescent

Personality assessment of children and adolescents experiencing an early, profound hearing loss is hampered by the lack of instruments standardized and/or developed primarily for use with deaf clients. Further compounding the problem are the relatively few psychologists trained in and/or experienced with deaf personality assessment. This article reviews the rudimentary requirements for personality assessment with the deaf and critiques the available personality tests that are either used or useable in assessing the deaf.     

Perceptual organization and focused attention: the role of objects and proximity in visual processing.

The influence of the Gestalt grouping principles of similarity, closure, and proximity on the size of the response-compatibility effect was examined in a focused attention task. In three studies, subjects responded to a centrally located target and attempted to ignore adjacent distractors. The distractors, which served as targets on other trials, could be compatible, incompatible, or neutral with respect to the response of the target. In addition, the distractors and the target could be embedded in the same object, presented in the same color, presented on different objects, or presented in different colors. The typical response-compatibility effect (B. A. Eriksen & C. W. Eriksen, 1974) was found when the target and distractors were embedded in the same object or presented in the same color. Performance was poorer when the target was surrounded by response-incompatible distractors than when it was surrounded by response-compatible distractors. However, the response-compatibility effect was eliminated when the target and distractors were embedded in different objects, even when the distance between the items was less than .25 degrees of visual angle. Furthermore, the response-compatibility effect was of intermediate size when the distractors were not grouped strongly with the target or with neutral flankers. The results are discussed in terms of space- and object-based models of visual attention.     

Perceptions of current and ideal body shape of athletes and nonathletes

This study was done to examine the relationship between sex and perception of body image among athletes and nonathletes. A total of 211 men and women athletes and nonathletes completed a questionnaire which asked them to identify from a nine-figure body-silhouette scale their current image and the image that they thought was most ideal. t tests showed no significant differences for men based upon athletic participation and that both athletes and nonathletes were satisfied with their body image. However, when comparing current image and ideal image, significant differences were found for women athletes and nonathletes. These data support previous research documenting women's dissatisfaction with their body images and show athletic participation is not associated with this perception.     

New assessments of weight-related body image derived from extant instruments

A study of 79 female college students examined the reliability and validity of two new size/weight-related measures of body image. The Body-size Appraisal Scale and the Overweight Preoccupation Scale were derived from existing instruments. Analyses supported the internal consistency and 2-wk. test-retest reliability of both new scales. Correlations of scores on each scale with measures of anxiety about being fat, negative body-image affect and avoidance, restrained and bulimic eating, and depression support their concurrent and construct validity. Scores on the Overweight Preoccupation Scale were also related to the extent of investment in physical appearance. Regression analyses indicated that each new scale could be predicted from several other conceptually relevant body-image attitudes, even after actual body weight was controlled.