Environmental stress and blood glucose change in insulin-dependent diabetes mellitus

Blood glucose (BG) response to psychological stress in insulin-dependent diabetes mellitus (IDDM) patients has not been firmly established. We report a study designed to address the gaps and methodological difficulties reviewed. Subjects with IDDM were exposed to two sessions (12 weeks apart) of two 20-min standardized stressors (active and passive) and a control condition administered in counterbalanced order. To measure BG response, subjects were connected to a glucose/insulin infusion system providing continuous BG measurement. Mood checklist measures were obtained at prestressor, poststressor, and recovery periods. During the first session of testing, the active stressor was associated with significantly more absolute change in BG response than the passive stressor. Results also indicate that IDDM subjects' BG response to this active stressor was idiosyncratic but significantly reliable over time.     

Sensation-seeking motivation and social-support moderators of the life stress/illness relationship: some contradictory and confirmatory evidence

The present study examined the relationship between measures of life change and reported physical and psychological symptoms as a function of the person's degree of sensation-seeking motivation (SSM) and of social support. A sample of firefighters was tested and showed that, contrary to previous reports, those relatively high in SSM showed a significantly stronger relationship between life change and illness than did those relatively low in SSM. Social support, however, did act to reduce the relationship between change and illness, in line with the evidence from previous investigations.     

A COMPARATIVE STUDY OF INSTRUMENTAL LEARNING BY PRESCHOOL CHILDREN IN PAPUA NEW GUINEA AND AUSTRALIA1

Instrumental learning of preschool children in Papua New Guinea (PNG) and Australia (AUST) was compared using two tasks (imitative and nonimitative) and two rewards (social and nonsocial). There were no differences between the two groups in the rate of acquisition measure of trials to criterion. PNG children made more late responses during acquisition and, for nil responses, there were group x task and group x reward x task effects. In the extinction phase, there were two main effects for trials to criterion: PNG children were more resistant to extinction than AUST children, and there was greater persistence in responding after social reward regardless of nationality. Reward x group, reward x task, and reward x group x task interactions also were observed in the extinction trials to criterion. In addition, there were three main task effects during extinction for other responses: on the imitative task, more wrong responses were made, and on the nonimitative task, more extra responses and more paired responses were made. A subsidiary analysis compared the two culturally different but educationally similar groups comprising the PNG sample: no major differences were isolated in acquisition or extinction.     

Asymmetrical stimulus control and the mirror-image problem

An analysis of the mirror-image discrimination literature revealed a number of inconsistent and paradoxical results. A unifying conception was proposed and it was argued that lateral mirror-image stimuli constitute a special class of problems on which effective performance is related to the introduction of an asymmetrical event into the task. Some implications were derived and tested in two experiments. First, five different response modes were compared for children required to discriminate two lateral or up-down mirror-image stimulus pairs. Acquisition was significantly faster on the latter problems. On the former, it was shown that responding to just one side of the lateral mirror-image stimuli led to significantly faster learning. Subsequent generalization tests indicated control by one part of the stimulus display for those who responded to one side. Next, Ss unable to learn the problem in Experiment I were given further acquisition trials. Only those children given training designed to promote selective stimulus control learned the problem.     

An evaluation of methods for behavioral investigations of teleost audition

Auditory thresholds have been determined for the goldfish by six groups of workers and the data in the experiments varied by as much as 20–30 dB. In order to isolate the basis for this variability, auditory thresholds were determined using conditioned suppression of respiration and method of limits. These thresholds were very similar to those obtained with avoidance conditioning and a tracking method for threshold determination. Acoustic procedures were kept constant in the two series of experiments, and it appears that wide variation in auditory thresholds for goldfish shown in different experiments is due to acoustic conditions in the experiments.     

Book reviews

Studies in Religious Fundamentalism. Ed. L. Caplan The Macmillan Press Ltd, 1987 ISBN 9 78033 419748 £29.50(h/b).

Trying Trialogues: Pluralism and Prejudicial Pluralism. David Kerr and Dan Cohn‐Sherbok (editors). Christians, Muslims and Jews, Conference of Christians, Muslims and Jews, Birmingham, 1984, no price given. pp.IV, 384     

Unavoidable gridshock without scrambling circuitry from a faradic source of low-radio-frequency current

A high-voltage radio-frequency stimulator was used as a source of motivational footshock in studies of conditional suppression. The circuit of the stimulator is presented schematically, then discussed in terms of affect induced by, gross behavioral response to, and electrical characteristics of, the stimulus. Near daily use of the stimulator across 6 months of formal assessment revealed that nonscrambled presentations of footshock via a grid of aluminum bars invariably resulted in stimulation of rat Ss and generated highly efficient conditional suppression of operant responding. While the stimulator was primarily designed to permit unconfounded presentation of gridshock in a 2,450-MHz microwave field, its simplicity and reliability suggest application in other situations requiring motivational shock.