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OCR for page 1
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
.;
OCR for page 2
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,
OCR for page 3
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
OCR for page 4
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~.
OCR for page 5
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
OCR for page 6
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.
Representative terms from entire chapter:
aging population
