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Solution: Reduction of
physical work has a micro- and a macrosolution. The microsolution involves
knowledge of "psychophysical" findings such as given by Fitt's
law. Professor Fitt studied the mathematical relation between the time
required for a subject to move a stylus to a target and the accuracy to
hitting the target. His research found that the movement time decreased
when the target was larger (see Figure 6).
Doubling the width of the target effectively cut the time in half! Our
lesson is clear. Bigger buttons are faster! We can add here that larger
targets also provide more space for clear button labels. Many commercial
applications use short button labels and we may feel obliged to imitate
that style. However, in corporate applications, users interact with many
more screens, and have less time to "learn" the cryptic button
labels. Thus, you should feel comfortable in creating longer button labels
if it speeds learning and reduces errors. For example, a button that reads
"Employee charitable contributions last month" could be far
more productive than "Contributions".
The macrosolution to reducing motor work requires standardization. Designers
who work in a group on a given application must coordinate their design
choices in order to provide consistency for their users. We recommend
use of "widget selection rules" to guide the group (see Figure
6). Note that the rules account for keyboard vs. mouse tasks, available
screen space, and list length, among other parameters. We include a complete
set of custom selection rules in all the standards we create for clients.
Another plus--the rules limit the developers
to a subset of all widgets. This means users get a lot of practice on
the subset. Try to save users the challenge of constantly learning new
widgets and confronting strange-but-true interactions of widgets with
unique behaviors (see Figure 7).
CONCLUSIONS Using the mouse appears simple. Even kids
can use it. In fact, the apparent simplicity
has been the source of many of the problems we pointed out in the column.
Designers forget that cryptofactors can influence the work required for
mouse usage such as extra visual search, forgetting to use keyboard methods,
and overwhelming users with intellectual demands. These burdens add the
Tyrannosaurus to the innocent Rodentia
Plasticae.
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Figure 7. A sample of strange siamese
widgets we have seen. Although each may have solved an apparent
design problem, the agony of interpreting them afresh is too much
to inflict on innocent users. Tyrannosaurus run amok.
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By the way, the OB-1 game turned out to be the all-time best selling
CD-ROM during the "age of information." That age ended in 2006
with the advent of quantum computing and the accompanying solutions to
problems of sustenance, political instability, and general craziness.
Then we got the "age of wisdom." People found they could lead
much more enjoyable lives than sitting in front of a terminal or even
talking to one.
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