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Introduction ~ the decade between 1990 and 2000, the U.S. population is expected to increase by 7.1 percent. Greater growth is forecast for the segment aged 55 and over. This group wiD increase by 11.5 percent a gam of over 6 minion persons. By fan the greatest growth in the over 55 age group wiD be among individuals 75 and older- an am crease of 26.2 percent or a gain of nearly 4.5 million (U.S. Department of Commerce, Bureau of the Census, 1988~. As the baby boom generation of the 1950s grows older, it wiD push upward the bulge in the population age distribution well into the next century. Thus, the graying of America may be a feature of our society for some time to come. How well will the large population of older Americans be able to live and function independently, carrying out the activities and tasks essential to an acceptable quality of life? This question is being posed with increasing frequency by researchers and policy makers who know that aggregated changes in circumstances and functional capacities affect the ability of older Americans to complete desirable and essential life activities. For example, about 5 percent of persons 65 years and older (about I.5 million) now reside ~ institutional settings. An estimated 2.S million individuals In this age group need some type of assistance in carrying out everyday activities (O~ce of Technology Assessment, 1985~. As the elderly population lives longer, larger numbers of individuals will require help. In general, aging is known to be accompanied by progressive changes in physiological and psychological functioning. These .;
2 IIUMAN FACTORS RESEARCH NEEDS FOR AN AGING POPU=UON changes occur as the result of ontogenetic events (e.g., decline in visual acuity); historical events (e.g., new technologies ~d living patterns); and life events (e.g., retirement, accidents). Taken to- gether these events alter, In a highly variable fashion, an individual's adaptive capacities. The task for the human factors engineer is to understand how the characteristics and needs of individuals change over the course of the adult life span and to devise strategies to ac- commodate these changes through the design of appropriate objects, tools, living envirorunents, and organizational systems. This report attempts to spotlight this problem and what is needed to help resolve it. It discusses how the relevant characteris tics of people are distributed across age groups and how performance changes with age. It suggests areas where human factors research is required and outlines strategies for translating human factors knowI- edge and research into practical improvements for the aging popu- lation. The intent is to stimulate and encourage the human factors research and engineering disciplines to address the needs of older adults. BACKGROUND Early in the planning stages of the project on human factors Ad aging, it was decided to structure the study around the functional capabilities of aging persons and the environmental demands made on them. It was felt that consideration of the interaction between task and ability as a function of the aging process would demonstrate the status of human factors in these areas, and would suggest promising lines of inquiry leading to more effective human factors interventions. In order to address efficiently the anticipated range of issues, a matrix was devised (Figure 1) that consisted of a set of rows, each dealing with an aspect of living (e.g., transportation) in which age- related problems knight arise, and a set of columns, each consisting of a group of characteristics or functions (e.g., cognition) of individuals that tend to vary with age and could, therefore, influence adapta- tion to one or more of these aspects of life. The task and activity categories (rows) chosen for examination were transportation and corrununication, home activities, work activities, leisure activities, and safety and security-related tasks. Work activities were further subdivided into patterns of employment and work performance. The functional categories (columns) included sensation and perception,
INTRODUCTION = i_ Functional Ability Sensory/ Physicalt Perceptual Physiobg=' Cognitive/ Psychomotor Transportation Home l l l Workplace | l l Leisure Safe~lSecurity ~ ~ T FIGURE 1 T~k/Activity: Functional Ability Matrix 3 physical chazactermlics, physiological function, and cognitive and psychomotor performance. For each task/acti~rity category, an expert was inherited to prepare a worlring paper outlining the task and performance requirements in each of these domains ~d describing the special problems that arise in each as a concomitaIlt of advanced age. For the function al abi] r categories, an expert ~ each area was merited to prepare a paper outlining what is known about how the function changes with age and the potential implications of these changes for successful independent living. At the workshop the experts were Eked to summarize the major points of their working papers and lead discussion of relevant hum" factors issues. The overall scheme was to consider the broad range of living tasks, to try to understand the demands of these tasks, and to identify what is known and what is not known about the ways in which aging modifies task performance and changes the requirements for design and enviromnental support for these activities. The discussion of the problems of the aging population, what is known about them, and what needs to be learned from future research, across a variety of areas dealing both with the nature of
4 HUMAN FACTORS RESEARCH NEEDS FOR AN AGING POPULATION problems faced by older people and with their characteristics and abilities, led to the unique perspective reflected ~ this report. OVERVIEW There exists a considerable body of knowledge regarding human aging. In general, aging is characterized as a nonuniform set of progressive changes in physiological and psychological functioning. While the onset, cause, and extent of these changes vary considerably across any given population' important average performance trends have been documented. For example, average visual and auditory acuity decline considerably with age, as do average strength and speed of response. Changes in cognition are less well defined but include an average loss of at least some kinds of memory function, declines in perceptual flexibility, slowing of ~st~rnulus encod~ng,~ and increased difficulty in the acquisition of complex mental skills. It is also known that some tasks such as driving, using stairways, and bathing, pose performance and safety problems for older people with much greater frequency than for younger people. However, details of how age-related changes ~ function mediate performance on these types of tasks is not yet known. For example, the fact that the incidence of fads among the elderly is high (Sterns, Barrett, and Alexander, 1985) has Creaky stimulated research aimed at understanding factors unique to the elderly that predispose them to falls and at identifying intervention strategies to remedy the problem. While progress has been made, falls are still a major health hazard for the elderly, and we do not yet fully understand the cognitive, design, or other factors that contribute to these accidents. Likewise, the reasons for the dramatic slowing of response with age are not clearly understood (Salthouse, 1985), and a detailed and coherent account of how information-processing capacity changes with age is still lacking. In addition, the distribution of age-related differences in such abilities as hand coordination and strength has not yet been specified, nor has the degree to which these differences are mitigated by such factors as regular exercise and practice been identified. For example, while it is known that hand grip strength tends to decline with age (Montoye and Larnphier, 1977), the sig- nificance of this loss relative to the requirements of operating tools (e.g., using kitchen utensils or opening various types of containers or doors) has not been sufficiently investigated (Faletti, 1984~.
IN1:ROD ACTION s Similarly, while it is known that visual functions such as static visual acuity, dark adaptation, accommodation, contrast sensitiv- ity, and peripheral vision decline, on average, with age (Kline and Schieber, 1985), it is not known in detail how these changes affect such tasks as driving a car or working at a visual display terminal. Knowledge of the declines In other sensory systems, such as auditory and vestibular senses, and their implications for the performance of everyday activities such as telephone or television communication is even more scarce. Questions can also be raised regarding the im- plications of age-related changes in cognition for the performance of mentally demanding tasks such as driving or piloting. Not only is the knowledge base of problems and needs on which to found research on ameliorative intervention uneven, but demonstrable accomplish- ments of intervention to date are fragmentary at best. This is not to suggest that ad of the needs of the elderly have been ignored Manufacturers have in fact devoted considerable resources to such aids as glasses, hearing aids, walkers, and other devices that are used by the frail elderly as well as the young handicapped. However, even these relatively weD-developed areas of rehabilitative medicine and cornrnercial development could profit from additional human factors task analysis and design. There is a need for a better engineering response directed at the problems encountered by older persons in the whole spectrum of work and living activities. ~ addition to improving the knowledge base and making tech- nology more responsive, better dissemination of knowledge and wider implementation of remedial techniques akeacly available are needed. While in the gerontological and safety communities much is known about the routine activities of older persons, ~ the wider human factors community little attention has been paid to the problems en- countered by the elderly. For this reason, despite an available body of literature, current knowledge about the elderly has not generally been translated into better policy or better design. In Section 2, we provide an overview of what is known about human factors relative to the problems associated with aging. We discuss the manner in which individual characteristics are distributed across age groups and how task demands and performance vary with age. This discussion generally follows the matrix devised for the workshop and is an exemplary rather than exhaustive coverage of the field. In Section 3, we take up the question of what is known and what needs to be known. In Section 4, we discuss research needs in terms of gaps in the knowledge base, opportunities to conduct
6 HUMAN FACTORS RESI3ARCH NEEDS FOR AN AGING POPULATION needed research, and research priorities. In Section 5, we make some strategic recommendations for potential future efforts of the National Research Council or other interested organizations that would con- tribute tows translating human factors knowledge and research into additional improvements in the lives of aging people. In par- ticular, we discus the desirability of future workshops focused more directly on particular task domains. We recommend the creation of internships and thesis support for graduate students working in this area, and we discus the possibility of extended Sumner sern~nars,~ specifically constructed data bases, and/or guidelines on human fac- tors and aging. We also discuss ways to encourage the incorporation of existing and forthcorn~ng knowledge and techniques into general handbooks, design guidelines, and codes In use by professions such as architecture and product design to accommodate the needs of the elderly. Each section of the report is treated independently, and it is rec- ogn~zed that there is some overlap among them regarding references to needed human factors research. However, the general assertion holds true that, within each of the activity are" discussed, there are large gaps in our existing knowledge.