Ergonomics and Aging - Fundamentals and Assessment Tools for Occupational Ergonomics - page 409

they are susceptible to biases such as the framing effect that also influence younger adults' decisions
(Mayhorn et al., 2002). While some suggest that older adults are more cautious decision-makers than
younger adults (Green et al., 1994), the speed and quality of decision-making is often found to be age
invariant (Dror et al., 1998).
17.6 Attention
Attention is a ubiquitous component to information processing; it involves selection, vigilance, and
control (Parasuraman, 1998). In the workplace, attention ability would be most pertinent for tasks
that involve finding given information among similar information, doing two tasks at the same time,
selecting relevant information while inhibiting irrelevant information, switching from one task to
another, and detecting rarely occurring information over a prolonged period of time. The ability to
apply mental effort to something for a sustained period of time appears to be relatively preserved
with age, unless the task involves perceptual discrimination (Deaton and Parasuraman, 1993).
However, there is evidence that older adults are less able to select relevant information (e.g., Allen
et al., 1994) and to inhibit irrelevant information compared to younger adults (e.g., Hasher and
Zacks, 1988). Furthermore, some research suggests that visual selective attention, which involves select-
ing relevant visual information while inhibiting irrelevant visual information, is influenced by aging (e.g.,
Carlson et al., 1995; Connelly et al., 1991; Hasher et al., 1991; McDowd and Oseas Kreger, 1991).
However, simple displays (Humphrey and Kramer, 1997), low-perceptual load (Madden and Langley,
2003) and adequate practice (Fisk and Rogers, 1991) minimize age differences.
Research has also examined selective attention to auditory information. Although some research has
demonstrated an age-related decline with regard to auditory selective attention (e.g., Barr and Giambra,
1990; Panek and McGown, 1981), more recent research showed that once age-differences in auditory per-
ception were controlled older and younger adults were equally affected by irrelevant information
(Murphy et al., 1999).
Furthermore, in a recent meta-analysis of dual task performance, older adults' speed and accuracy
were compromised to a greater extent compared to younger adults (Verhaeghen et al., 2003). The rami-
fications of these findings for the workplace are that older adults may perform attention-demanding
tasks better if they are less complex and rely less on working memory. Furthermore, age-related
declines in attention may be minimized when older adults are given adequate practice, when they
are not distracted by irrelevant information, and if they perform complex tasks separately rather
than concurrently.
17.7 Motor Control
Accompanying age-related declines in perception and cognition are declines in older adults' abilities to
initiate and control motor movement. Older workers in certain professions such as factory assembly lines
might be differentially affected by these declines than workers whose job-related performance is less
reliant on physical activities (Panek, 1997). As people age, motor function slows such that movements
require more time for completion, continuous movements become more difficult, and deficits in
coordination are observed (Vercruyssen, 1997).
The relationship between movement time and accuracy is reflected by Fitts' Law (Fitts, 1954), which
states that movement time is linearly related to the difficulty of the movement. Thus, a speed-accuracy
trade-off results when more time is required to complete difficult movements that require increased
precision. General findings from previous research that investigated older adults' motor control by
observing the speed-accuracy trade-off indicated that older adults are slower than younger adults
when performing the same movements because they tend to place greater importance on accuracy
(for a review, see Walker et al., 1996). The issue of speed-accuracy trade-off may be important in
many types of work tasks. For instance, Fitts' Law has been applied to movement tasks as diverse as