Effects of task instructions and oscillation frequency on bimanual coordination

Increases in the oscillation frequency of bimanual movements produce a switch from an anti-phase (180° relative phase) to an in-phase (0° relative phase) coordination pattern. This finding is observed when subjects are instructed not to intervene when they feel themselves slipping out of the anti-phase pattern. The question addressed in this study concerned how performance would be affected if subjects were instructed to try to maintain the pattern at all times. This issue was addressed using two separate groups of subjects: one group was given the do not intervene instructions, the other group was told to try to stay with the pattern at all times. Forearm rotations were tested in 15 s trials, paced by an auditory metronome set at 1.0, 1.5, 2.0, 2.5, and 3.0 Hz. Frequency distributions of the point estimates of relative phase were analyzed. The Do not Intervene group replicated previous findings, as indicated by the development of a bimodal histogram of relative phase distributions with increases in oscillation frequency. However, a very different pattern of findings emerged with increases in oscillation frequency for the group told to stay with the anti-phase pattern. Rather than a bimodal distribution being developed, the data maintained 180° as its central tendency — no secondary distribution developed around 0° relative phase. These data suggest that volitional control can over-ride the inherent dynamical tendencies of the motor system.     

Teaching peer reinforcement and grocery words: An investigation of observational learning and instructive feedback

A multiple probe across behaviors design, replicated across participants, assessed the effectiveness of constant time delay in teaching appropriate peer reinforcement and grocery words to 3 elementary students with moderate intellectual disabilities. Additionally, pretests and posttests assessed the acquisition of the participants' observational learning (acquisition of peers' grocery words) and instructive feedback (related information supplied by the teacher in the consequent event). Results indicate that the participants learned (a) how to appropriately reinforce peers, (b) to read their grocery words, (c) some of the targeted stimuli of their peers, and (d) much of the instructive feedback that was associated with each of the grocery words. Maintenance data indicate that the participants maintained their target grocery words at high levels of accuracy.     

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.     

Police evaluation research: an experimental and cost-benefit analysis of a helicopter patrol in a high crime area

The significance of a helicopter patrol procedure directed toward prevention of home burglaries was evaluated from experimental and cost-benefit perspectives. The helicopter patrolled one city zone from 9 a.m. to 5 p.m. for two 12-day periods. Each 12-day period was separated by a baseline period in which only normal patrol-car levels were maintained. Significantly reduced burglary levels during the intervention periods, compared to baseline periods, documented the experimental significance of the helicopter procedure. The cash costs of implementing the patrol procedure were compared to two estimates of the resulting cash benefits. This latter cost-benefit analysis was supplemented by a discussion of the intangible costs and benefits of the helicopter procedure. Taken together, these analyses documented that the marginal costs of the helicopter intervention were exceeded by all estimates of benefits.     

The relative effectiveness of alternative job sources

Vocational research has focused on the occupational choice process and the individual's adjustment to work. Very little research has examined the job search process in which the individual must engage in order to implement occupational choices. This study examines one dimension of the job search process: the relationship between job source and subsequent work experiences. The data reveal that when the respondents initially entered the labor market, those relying on formal job sources tended to work in higher-level occupations and in jobs more closely related to their training than their counterparts who used other job sources. In the longer run, the labor market advantages associated with the use of formal job sources dissipated for the engineering majors but tended to persist for the business alumni.     

New perspectives in temperament/personality research: The “Behavioral” model of the Warsaw group

This paper reviews the theory and research of the Warsaw school of differential psychophysiology, which has modified and extended the typologic model constructed by Teplov and Nebylitsyn. While Soviet theory still favors a relatively inflexible structure of nervous system properties as the biologic basis of individual differences in personality, Strelau and colleagues, in line with the action/activity model of Vygotsky and Tomaszewski, begin with the premise that for every individual there is a specific, genetically determined optimal level of arousal, a necessary background for fullest emotional and intellectual development. The person strives to create this optimal climate through an active process of stimulation control, achieved primarily through enhancement or dampening of reactivity—which describes innate responsivity in the reacting systems to both sensory and emotional stimuli—through various hormonal ‘tuning’ mechanisms and through “appropriate” activity, reflected in different cognitive styles and preference for certain work conditions. Such activities aim to ensure comfortable physical and psychologic environments, in which the individual can avoid conflict and stress. The system regulating and integrating such control mechanisms is the core of personality. Investigations of the Warsaw group on relationships between reactivity and different forms of stimulation seeking/control—risk-taking, work style preferences, cognitive style, defense mechanisms, for example—and between reactivity and tolerance of stress and conflict and their speculations about the neurophysiologic and endocrinologic mechanisms of stimulation control are described, as are a number of questionnaires developed by this group to measure reactivity, the temporal parameters of response, and stimulation-seeking in a variety of occupational and social contexts.     

Picture perception: An analysis of visual compensation

Although geometric information is altered when a picture’s viewing point is changed, such changes often do not affect perception. Two experiments assessed pictorial perception relative to the distortions introduced by viewing point dislocation. Results provide a psychophysical demonstration of pictorial compensation and suggest that it is based on the discrepancy between the actual and an assumed-correct viewing position. An explanation of pictorial compensation is offered that could be applied to direct picture perception and to picture-in-a-picture perception.     

Empirical sleep assessment in the home: A convenient,inexpensive approach

We have previously reported on a sleep assessment device (SAD) that addresses shortcomings inherent in self-report sleep data and polysomnography. The SAD produces a sleep record by tape recording subjects' verbal responses to auditory cues spaced at fixed intervals throughout the night. In prior studies, the SAD proved to be a reliable and valid assessment tool according to electroencephalographic comparisons. Herein, we report on the unassisted home use of the SAD by eight normal volunteers and four bedmates. Subjects and bedmates completed sleep questionnaires for 12 nights and subjects also employed the SAD the last 6 nights. Comparisons of subjects and bedmates self-report sleep data before and during SAD use indicated that the SAD did not disrupt sleep. Subjects were able to self-administer successfully the SAD in their homes. SAD data closely matched subjects' self-report data. The present study found the SAD to be an accurate, unobtrusive, and easily utilized empirical measure of sleep in the natural environment. In so doing, it extends the demonstrated reliability and validity of the SAD from the sleep laboratory to the home with normal sleepers.