Environmental Engineering Reference
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accuracy of movement (Chaput & Proteau, 1996), reaction time (Light, 1990; Sparrow et al.,
2006; Yan et al., 1998), strength (Roos et al., 1997; Vandervoort, 2002), hand dexterity
(Contreras-Vidal, Teulings, & Stelmach, 1998; Seidler, Alberts, & Stelmach, 2002), and
postural control (Jonsson, Henriksson, & Hirschfeld, 2007; Koceja, Allway, & Earles, 1999;
Mourey et al., 1998; Romero & Stelmach, 2003). En masse, these changes have the potential
to contribute to a spiral of disuse and loss of function that often characterizes the process of
aging. Due to the tendency for visual dominance in aged humans (Lemay et al., 2004), and
the task specificity of human movement (Proteau, 1992), the fact that visual sensory
feedback is much less rich in a virtual than natural environment makes it imperative to
study human performance in such surroundings. Research is needed to improve our
understanding of sensorimotor changes, and their consequences for performance, for an
aging population interacting in three-dimensional environments.
2.2 Three-dimensional virtual environments and human computer interaction (HCI)
across the lifespan
Today, the users of computers include people from all age groups. Very little information is
available on how the performance of individuals in a VE changes throughout the lifespan as
a function of the natural aging process. Prior to designing programs for individuals in
special subgroups, such as rehabilitation programs designed for patients with neurological
lesions, it will be important to understand what age-specific requirements will be beneficial
to the user. For instance, because there is a paucity of information on how healthy adults
in the older age groups commonly affected by stroke interact in VEs, it is likely that a
system designed as an adjunct to standard rehabilitation will struggle to gain success
without a foundation of baseline knowledge. This level of information regarding subjects
of various age groups will greatly assist in producing successful, cost-effective VEs.
Unfortunately, although computers have been commonplace in homes and work-
environments for decades, the literature on interface design as it relates to age is only very
recent, and is limited in scope. Early computer interface design relied primarily on the
intuition of the designer (Hawthorn, 2001; Hawthorn, 2007). There was a distinct disparity
between what designers recognized as necessary interface components and what was
truly usable by the lay population. As access to computer technology improved and
allowed the spread of computers into the hands of consumers, a necessary change to user-
centered design followed. Typically, however, in order to be a feasible process, the
representative users must have a basic level of proficiency with computer skills and
language. This resulted in a general exclusion of both young and old age groups from the
design process. In the late 1990's, interest in age-specific design increased, and there is
now a reasonable body of knowledge on the design of standard computer interface
systems for various age groups.
While the bulk of age-specific computer design information relates to ways to improve
cognitive performance through specific training or tutorial methods (Hawthorn, 2007), there
is some scientific literature which explores the areas of human motor control (Laursen,
Jensen, & Ratkevicius, 2001; Smith, Sharit, & Czaja, 1999). Most of this information centers
on the input device, specifically mouse usage in older adults. Smith et al. (1999) reported
that there are many age-related changes in performance, and in general, it is quite difficult
for older individuals to use a mouse. The act of double-clicking seems to consistently be the
