Documents mental work capacity 6 results

There is considerable evidence in the ergonomics literature that automation can significantly reduce operator mental workload. Furthermore, reducing mental workload is not necessarily a good thing, particularly in cases where the level is already manageable. This raises the issue of mental underload, which can be at least as detrimental to performance as overload. However, although it is widely recognized that mental underload is detrimental to performance, there are very few attempts to explain why this may be the case. It is argued in this paper that, until the need for a human operator is completely eliminated, automation has psychological implications relevant in both theoretical and applied domains. The present paper reviews theories of attention, as well as the literature on mental workload and automation, to synthesize a new explanation for the effects of mental underload on performance. Malleable attentional resources theory proposes that attentional capacity shrinks to accommodate reductions in mental workload, and that this shrinkage is responsible for the underload effect. The theory is discussed with respect to the applied implications for ergonomics research.

The combined effects of city noise and luminance of the computer display were evaluated from the changes in lymphocytes and mental activities of participants. Healthy male students were tested under the following four experimental conditions: (1) a calculating task on a video display terminal (VDT) with luminance of 90 cd m-2 without city noise; (2) a calculating task on a VDT with luminance of 20 cd m-2 without city noise; (3) a calculating task on a VDT with luminance of 90 cd m-2 with city noise of 70 dB(A); and (4) a calculating task on a VDT with luminance of 20 cd m-2 with city noise of 70 dB(A). A visual reaction test (VRT) was performed, and critical flicker fusion frequency (CFF), heart rate (HR), numbers of circulating white blood cells (WBCs), lymphocyte subsets and subjective symptoms of fatigue were measured (1) before; (2) just after; and (3) 30 min after each 60 min test. Subjective symptoms of fatigue significantly increased just after experiments conducted under the two noisy conditions. VRT and CFF showed significant changes in the case of the highluminance display with noise. WBCs and neutrophils showed significant increases in the two quiet conditions. These results suggested that high luminance with noise had the most effect on subjective fatigue and mental activities.

"At present we are looking at increased life expectancies and prolonged periods of employment. The aged workforce as a natural result of this phenomenon presents society with great challenges. At the 2nd International Symposium on Work Ability held in Verona, Italy between 18 and 20 October 2004 this problem was scientifically addressed. This book Assessment and Promotion of Work Ability, Health and Well-being of Ageing Workers contains the majority of papers presented here. The book reflects the major themes of the meeting which are factors affecting work ability and employability of ageing workers, assessment of work ability in different occupations, Evaluation of work-related problems of ageing workers and promotion of health and work ability. You will find very useful information and examples of methods, research and ongoing interventions."
(Publisher's abstract)

"This booklet describes the work ability index, a method developed by the Finnish Institute of Occupational Health for providing an assessment of how well a worker is able to perform his or her work. The index is determined on the basis of answers to a series of questions which take into account the physical and mental demands of the work and the worker's health status and resources. The score calculated from the responses depicts the worker's own concept of his or her work ability. Other topics discussed: example of the determination of the index; reference values; follow-up measures."