Circadian factors during sustained performance: Background and methodology

Cornell University Medical College, Westchester Division, The New York Hospital, White Plains, New York It is well established that there is a complex timekeeping mechanism in the human brain. This mechanism is associated with a variety of physiological and psychological rhythms having a period of about a day, and thus referred to as circadian rhythms. The circadian system has recently been modeled in terms of two underlying oscillators, one much more resistant to changes in routine than the other. These oscillators are considered to be endogenous, that is, internal to the organism, and not reliant for their existence upon changes in the person’s environment or general behavior. They thus continue to run even when the sleep/wake cycle is suspended, as in sustained operations. Thus, by their very nature, sustained operations require the individual to override the inputs that are coming from his or her circadian system (especially the indication that sleep is required). The aim of this paper is to provide a background to the area of circadian rhythms research, including a section on the methodology, so that the impact of the circadian system on sustained operations can be better understood.     

Pain as purgation: The role of pathologizing in the life of the mystic

Since Descartes, man has been defined in terms of body and spirit only. Yet there is a third term that is of crucial importance for the founding of a psychology of suffering. The realm of psyche, or soul, is a middle ground between the spirit and the body in which the psychological forces of one's life find expression. A psychological approach to the anguish of the suffering soul can be found within the writings of the early desert fathers as well as in the paintings of Hieronymus Bosch. The penitent must learn patience in the face of his suffering, before he can experience the joy of spiritual maturity.A famous anchorite came to take counsel on high things with the abbot Pastor, but the old man turned away his head, and the anchorite went away aggrieved. His disciple asked Pastor why he had refused to talk with a man so great and of such reputation in his own country, and the old man said that his visitor could speak of heavenly things, but that he himself was of earth. If he had spoken to me of the passions of the soul I could have answered him: but of the things of the spirit I am ignorant.Mr. Fischer is a member of the Psychology Department, University of Dallas, Irving, Texas 75060.     

Statistical significance tests for binormal ROC curves

Statistical significance tests are derived and evaluated for measuring apparent differences between an obtained and an expected binormal ROC curve, between two independent binormal ROC curves, and among groups of independent binormal ROC curves. A binormal ROC curve is described by two parameters which represent the spread of the means and the ratio of the standard deviations of the two underlying Gaussian decision variable distributions. To test the significance of apparent differences between or among ROC curves, approximate χ² statistics for each of the three tests were constructed from maximum likelihood estimates of the two parameters defining the binormal ROC curve. The performance of each test statistic was evaluated by simulating five-category rating scale data with equal numbers of noise and signal-plus-noise trials (set at 50, 250, and 500) for each of three typical ROC curves. For the significance test involving only one ROC curve, rating scale data were generated from the chance diagonal of the ROC space also. Although test performance was found to be somewhat dependent on the number of trials and on the location of the ROC curve in the ROC space, comparisons of the obtained and expected fractions of (falsely) significant results at various α levels showed the proposed statistical significance tests to be reliable under practical experimental conditions.     

Incidental learning,attention, and curiosity in squirrel monkeys calorie deprived as infants

The long-term effects of infantile malnutrition on information processing were studied in squirrel monkeys. From 2 through 8 weeks of age, four low-calorie infants were fed reduced amounts of a high protein diet, limiting their mean body weight gain to 23% of that of four well-fed controls, with all of this gain occurring during the first 2 weeks on the low-calorie diet. Thereafter, both groups received the standard diet ad libitum. At 68 weeks of age, incidental learning was tested by introducing shape cues that were redundant to the solution of a previously learned, two-choice, color discrimination. Removal of the color cues showed that the low-calorie monkeys had learned significantly less about the shape cues than had the controls. The basis for this incidental learning failure was then examined with an embedded-figures dicrimination, to measure attentional ability, and a novel stimulus substitution task, to measure curiosity. The groups did not differ in detecting embedded figures, but the low-calorie monkeys were significantly less likely than controls to select or handle novel stimuli that had been substituted for previously learned discriminative cues. It was concluded that undernutrition in infancy may induce a long-term strategy of only learning information which leads to an immediate reward, while suppressing the acquisition of information due to intrinsic curiosity.     

Conceptual development in learning-disabled and normal boys

In two related studies, a pictorial sorting task served as the means of measuring conceptual development in LD and normal boys. The studies found no differences in the bases on which groups were formed (perceptible attributes, function, or nominal class membership) or in the manner in which groups were structured (thematically, in complexive groups or superordinate groups). Furthermore, parallel developmental trends were found in both LD and normal subjects groups. These findings are not consistent with early studies of concept formation in brain-damaged subjects, most of whom were retarded. Subjects in the present studies were selected on the basis of clinical diagnosis of LD and average IQ. The findings of the present studies suggest that generalizations about conceptual abilities of LD children of normal intelligence should not be based on early studies of the effects of brain damage.