Computing stress

This article is based on a review of recent literature on “computing stress”; that is, on the psychological stress effects of working with computer systems. Current research into the sources of computer-related stress has tended to concentrate on those employees who operate Visual Display Units (VDUs), either on a full-time professional basis as word-processor (WP) operators, data-entry clerks, secretaries, or those dealing with enquiries from the public; or employees who use the VDU irregularly as part of their other duties. A few studies have looked at specific occupation groups, such as printers (Kalimo & Leppänen, 1985), information technology professionals (programers and analysts), process workers, and college students (Sproull, Kiesler, & Zubrow, 1984). Generally, however, research has been carried out on office workers, more often women, carrying out administrative tasks. An attempt is made to identify those potential work-related stressors that have been isolated by these studies, and also included are criticisms of the general methodologies used in many of them.     

Book reviews

Current Psychology -     

A Commodore 64-based experimental psychology laboratory

When used in conjunction with a 6522 interface board, the Commodore 64 (C64) computer can control and precisely time externally generated stimuli. A C64-based experimental psychology laboratory that uses these capabilities is described along with a set of programs that can be used to control experimentation. The pros and cons of using the C64 as a laboratory computer are discussed.     

A simple infrared photocell device and its interface to an Apple computer

This paper describes a simple infrared photocell circuit that is inexpensive and easy to construct. The light source and detector are housed inexpensively and are focused so the light and detector may be separated over significant distances. The circuit may be used in a variety of conditions, including total darkness and bright fluorescent lighting, without having to readjust or recalibrate the circuitry. Output from the circuit may be used to drive other transistors or electromechanical relays. With minimal additional circuitry and hardware the signal may be interfaced with an Apple computer.     

Training non-native speech contrasts in adults: Acquisition of the English /ð/-/θ/ contrast by francophones

Attention, Perception, & Psychophysics - Speech perception abilities are modified by linguistic experience to maximize sensitivity to acoustic contrasts that are important for one’s...     

Effects of flash luminance and positional expectancies on visual response latency

It is well established that human observers respond more quickly to visual targets that appear in expected locations than they do to ones in unexpected locations. These variations in simple reaction time have been attributed to a covert alignment of an attentional mechanism to the expected target location. The present experiments investigated the influence of strength of signal and strength of subject’s positional expectancy on the magnitude of this attentional effect. In the first experiment, target luminance was varied over a range of three log units, and it was found that the effects of luminance were essentially additive with the effect of the positional expectancy (i.e., the attention effect). The second experiment found that the magnitude of visual attention interacts with the information value of the precue used to create the spatial expectancy, although, once again, luminance had additive effects. The resuls are interpreted as indicating that, rather than influencing early visual processing, the act of attending to a spatial location operates fairly late in the detection process.     

Evidence for disparity change as the primary stimulus for stereoscopic processing

Subjects were able to respond to a lens-induced stereoscopic slant more quickly and more accurately when it was imposed on only part of a surface rather than on the whole surface. This shows that the presence of a stereoscopic boundary, where disparity is discontinuous, increases the efficiency of stereoscopic processing. This finding is not consistent with many current models of stereopsis.     

Minicomputer-administered tasks in the study of effects of sustained work on human performance

Six tasks administered on a MINC-11 minicomputer were used in studying the effects of long, continuous work periods and fatigue on physical and cognitive task performance. Submaximal physiological workload measurement was done during one of these tasks for a subject walking on a treadmill. The MINC-11 system is described, as are the six tasks programs. Four of these tasks measured various types of reaction times, another involved complex information processing, and one appraised moods, physical symptoms, fatigue, and the physiological status of subjects.     

Simulation analyses of space use: Home range estimates,variability, and sample size

Simulations of space use by animals were run to determine the relationship among home range area estimates, variability, and sample size (number of locations). As sample size increased, home range size increased asymptotically, whereas variability decreased among mean home range area estimates generated by multiple simulations for the same sample size. Our results suggest that field workers should ascertain between 100 and 200 locations in order to estimate reliably home range area. In some cases, this suggested guideline is higher than values found in the few published studies in which the relationship between home range area and number of locations is addressed. Sampling differences for small species occupying relatively small home ranges indicate that fewer locations may be sufficient to allow for a reliable estimate of home range. Intraspecific variability in social status (group member, loner, resident, transient), age, sex, reproductive condition, and food resources also have to be considered, as do season, habitat, and differences in sampling and analytical methods. Comparative data still are needed.     

Tonal frequency shifts and gaps in acoustic stimulation as reflex-modifying events

When a relatively weak signal, such as a mild tone, precedes an intense reflex-eliciting stimulus by an appropriate interval (about 100 msec), the amplitude of the elicited reaction is often reduced. It was found that in student volunteers a brief gap in a steady pure tone that occurred 150 msec prior to a mild tap to the glabella (the flat region between the eyebrows) could inhibit the eyeblink elicited by the tap. It was also found that a shift in tonal frequency across a gap in a tone was more inhibitory than a gap with no frequency shift, but it was no more inhibitory than the onset of the short second tone alone. The final study determined the minimum amount of frequency shift required to produce an additional inhibitory effect above that of a gap alone. The findings are discussed in terms of various aspects of sensory processing.