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Biomedical subjects

J Sharit

Publications and source records attributed to J Sharit.

11 recordsLinked to original sources
PubMed2000

The effects of whole-body restriction on task performance.

Many occupations, particularly involving maintenance operations, require individuals to perform both physical tasks and mental tasks in restricted spaces. Researchers have examined physical task performance under various restrictions; however, little research has investigated the effects of restricted space on cognitive tasks. Cognitive task performance in restricted spaces presents cognitive demands (i.e. the task itself) as well as additional physical demands (e.g. awkward postures), which may adversely affect task performance or operator workload. This research focused on the effects of whole-body restrictions on cognitive task performance. An experiment was conducted that examined 9 levels of restriction created in a laboratory: an unrestricted control, 6 single whole-body restrictions at two severity levels (2 lateral, 2 sagittal and 2 vertical) and 2 multiple restrictions (sagittal/vertical, lateral/sagittal/vertical). An inspection task served as the cognitive task. Behavioural, physiological and psychophysical measures were collected and analysed to measure the operator and performance effects. Operator response differences were found among the various forms of restriction as well as the severity level of similar forms of restriction. Increasing restriction significantly affected the behavioural and physiological operator response as opposed to the cognitive response.

Analysis of Variance↗
PubMed2000

A modeling framework for exposing risks in complex systems.

This article introduces and develops a modeling framework for exposing risks in the form of human errors and adverse consequences in high-risk systems. The modeling framework is based on two components: a two-dimensional theory of accidents in systems developed by Perrow in 1984, and the concept of multiple system perspectives. The theory of accidents differentiates systems on the basis of two sets of attributes. One set characterizes the degree to which systems are interactively complex; the other emphasizes the extent to which systems are tightly coupled. The concept of multiple perspectives provides alternative descriptions of the entire system that serve to enhance insight into system processes. The usefulness of these two model components derives from a modeling framework that cross-links them, enabling a variety of work contexts to be exposed and understood that would otherwise be very difficult or impossible to identify. The model components and the modeling framework are illustrated in the case of a large and comprehensive trauma care system. In addition to its general utility in the area of risk analysis, this methodology may be valuable in applications of current methods of human and system reliability analysis in complex and continually evolving high-risk systems.

Accidents↗
PubMed1999

Aging, motor control, and the performance of computer mouse tasks.

Because of the increased presence of computers in work and everyday life and the demographic "graying" of America, there is a need for interface designs that promote accessibility for older people. This study examined age differences in the performance of basic computer mouse control techniques. An additional goal of the study was to examine the influence of age-related changes in psychomotor abilities on mouse control. A total of 60 participants in 3 age groups (20-39 years, 40-59 years, and 60-75 years) performed 4 target acquisition tasks (pointing, clicking, double-clicking, and dragging) using a computer mouse. The data indicated that the older participants had more difficulty performing mouse tasks than the younger participants. Differences in performance attributable to age were found for the more complex tasks (clicking and double-clicking). Furthermore, age-related changes in psychomotor abilities were related to age differences in performance. We discuss applications to computer interface designs. Actual or potential applications of this research include specifications for computer mouse design to accommodate older populations.

Adult↗
PubMed1998

Guidelines for force-travel combinations of push button switches for older populations.

Current demographic trends indicating that older persons will comprise an increasingly larger proportion of our population points to the need for paying closer attention to age-related disabilities in designing products and environments capable of accommodating this population. This study addresses the development of design guidelines for push-button switches associated with a variety of consumer products commonly used by older persons. Three groups, each consisting of 12 male and female subjects, participated in the study, with all subjects over the age of 50 and the average age being 70 years. The groups were categorized on the basis of whether subjects were able-bodied, had arthritis affecting their hands or fingers, or had hand tremor; these categories were validated through the use of functional assessment tools. A scheme was developed to categorize commercially available switches based on force-travel combinations, and an experiment was conducted to assess the subject's ability to momentarily and continuously operate the switches, as well as to derive the subjective preferences for these switches. Based on observations from behavioral strategies, and graphical and statistical analysis of preferences, a set of design guidelines was proposed to enable consumer product designers and manufacturers to better accommodate the needs of both able-bodied and functionally impaired older adults.

Activities of Daily Living↗
PubMed1998

Age differences in attitudes toward computers.

It is commonly believed that older adults hold more negative attitudes toward computer technology than younger people. This study examined age differences in attitudes toward computers as a function of experience with computers and computer task characteristics. A sample of 384 community-dwelling adults ranging in age from 20 to 75 years performed one of three real-world computer tasks (data entry, database inquiry, accounts balancing) for a 3-day period. A multidimensional computer attitude scale was used to assess attitudes toward computers pretask and posttask. Although there were no age differences in overall attitudes, there were age effects for the dimensions of comfort, efficacy, dehumanization, and control. In general, older people perceived less comfort, efficacy, and control over computers than did the other participants. The results also indicated that experience with computers resulted in more positive attitudes for all participants across most attitude dimensions. These effects were moderated by task and gender. Overall, the findings indicated that computer attitudes are modifiable for people of all age groups. However, the nature of computer experience has an impact on attitude change.

Adult↗
PubMed1997

Feedback strategies for visual search in airframe structural inspection.

Feedback of information has consistently shown positive results in human inspection, provided it is given in a timely and appropriate manner. Feedback serves as the basis of most training schemes; traditionally this has been performance feedback. Other forms of feedback which provide strategy information rather than performance information may have a role in improving inspection. This study compared performance feedback and cognitive feedback in a realistic simulation of an aircraft structural inspection task. Performance (time, errors) feedback showed the greatest improvements in performance measures. Cognitive feedback enhanced efficiency measures of search strategy. When cognitive feedback consisted of visual representations of the path and the coverage of the search sequence, subjects also were able to use this task information to improve their search performance.

Adult↗
PubMed1994

Ageing, computer-based task performance, and stress: issues and challenges.

An emerging problem that encompasses both traditional ergonomic as well as macroergonomic concerns involves assessing the potential implications of computer-based tasks for older workers. An increasing older workforce and the influx of computer technology into a wide variety of work settings has motivated both a re-examination of the literature concerning ageing and work performance and research that more directly addresses the computer-interactive task domain. In this paper, we overview this literature and raise a number of crucial issues concerning potential age differences in performance and stress associated with computer-based tasks. Underlying our discussion throughout is the intention of identifying the challenges that await interested practitioners and researchers.

Adult↗
PubMed1993

Age differences in the performance of computer-based work.

This study investigated the extent to which age had an impact on the performance of computer-based work. Three simulated real-world computer-interactive tasks that varied in complexity and pacing requirements were evaluated. Ss included 65 women, ranging in age from 25 years to 70 years. The methodology encompassed physiological, subjective, and objective performance measures. The data indicated that previous computer experience and age had a significant impact on the performance of the 3 tasks. Increased age was associated with longer response times and a greater number of errors for all 3 tasks. Age also influenced perceptions of fatigue and task difficulty. The findings are discussed in terms of the implications for training and job design.

Adult↗