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Biomedical subjects

N Friedland

Publications and source records attributed to N Friedland.

7 recordsLinked to original sources
PubMed1995

Changes of brain anatomy in patients with posttraumatic stress disorder: a pilot magnetic resonance imaging study.

No abnormalities in magnetic resonance images were recorded in patients with posttraumatic stress disorder other than an increased incidence (50%) of a small cleft in the callosal-septal interface, a cavum of the septum pellucidum. A similar grade of cavum was obtained in 14% of normal volunteers matched for age, socioeconomic background, and military experience. The cavum is believed to have antedated the disorder and is conceived to be a neurodevelopmental aberration. The possibility that the cavum is a marker of vulnerability to stress in psychopathology is discussed.

Adult↗
PubMed1992

Controlling the uncontrollable: effects of stress on illusory perceptions of controllability.

Individuals' failure to exercise actual control over an event might be compensated for by trying to bolster a generalized, subjective sense of control. Control might then be sought by undertaking acts the effect of which on the environment is illusory. This observation led to the hypothesis that stress, which undermines persons' sense of control, would engender illusory perceptions of controllability. The hypothesis was tested in 3 experiments that required Ss to choose between 2 gambling forms. Although the 2 forms were essentially identical, 1 was designed to instill an illusion of control. The results showed that highly stressed Ss, compared with those who experienced low stress, preferred gambling forms that heightened perceptions of controllability.

Adult↗
PubMed1986

Stressors and tasks: how and when should stressors be introduced during training for task performance in stressful situations?

Studies on the training of individuals for task performance in stressful situations have typically evaluated procedures that simultaneously expose trainees to tasks and to stressors. Such procedures might create a mutual interference of the stressor with task acquisition, or conversely, of preoccupation with task acquisition with familiarization with the stressors. Using a sample of 180 males, the present study compared a procedure that temporally separates task acquisition from exposure to stressors ("phased training") with the more typical approach which combines the two ("combined training"). The comparison was carried out under varying degrees of stressor-fidelity representation in the course of training, and under two degrees of contingency between quality of task performance and the possibility of avoiding stress. The main result indicates that phased and combined training are equally effective under conditions of noncontingency. In a contingent condition, on the other hand, phased training proves to be significantly superior.

Analysis of Variance↗
PubMed1984

Dilemmas concerning the training of individuals for task performance under stress.

The relative effectiveness of five procedures for the training of individuals to perform tasks under stress was tested in a criterion situation, where subjects were requested to perform a visual search task under the threat of electric shocks. During training on the task, different groups of subjects received shocks of criterion-level intensity; milder than criterion-level intensity; gradually increasing intensity; randomly varying intensity. The last group received no shocks at all. The results pointed to three conditions for the enhancement of training effectiveness: minimal interference of exposure to stressors with task acquisition, familiarity with stressors characteristic of the criterion situation, and absence of unrealistic expectations about future stressors. However, none of the five training procedures meets all three conditions. Implications for the design of procedures whereby persons can be trained to perform proficiently under stress are discussed.

Humans↗
PubMed1982

Patterns of fidelity between training and criterion situations as determinants of performance in stressful situations.

The training of individuals for task performance under stress poses a dilemma concerning the degree to which stressor characteristics of the criterion situation should be represented with a high degree of fidelity during training. High fidelity training is likely to reduce the novelty of the criterion situation and familiarize the trainee with his emotional and physiological reactions to stress. On the other hand, the exposure of the trainee to high stress levels during training might interfere with task acquisition and intensify his fears and emotional sensitivity. This difficulty might be overcome with "graduated fidelity training" whereby the trainee is exposed to gradually increasing stressor intensities, starting with very low intensities and reaching, by the end of training, criterion-level stressor intensities. The empirical evaluation of this method, carried out in the present study, suggested that it is potentially more effective than high fidelity training. However, two conditions are necessary for the realization of this potential effectiveness. First, the trainee must be informed about the upper limit of stressor intensity which he might encounter in the course of training. In the absence of such information, graduated fidelity training might become highly ineffective. Second, the trainee has to perceive high quality performance as being instrumental for the removal or attenuation of stressors.

Electroshock↗