Cognition: Mental Representations, Problem Solving, and Decision Making - Foundations for Designing User-Centered Systems - page 168

Fig. 6.5 An airport check-in kiosk. The phrase ''Add SkyMiles,'' on the bottom, refers to their
frequent flyer program account number which, if the interface is rarely used, can (and did) require
the user to do extra work by asking an agent what SkyMiles is, and how to enter a frequent flyer
number
stimulus and the response should be compatible. This is typically seen as having
physical aspects of an interface (e.g., buttons) and displays (e.g., GUIs) match the
world that they are representing. So the buttons to call an elevator to go up should
be above the buttons that are used to call an elevator to go down. Systems where
mappings like these are supported are faster to use and can lead to fewer errors.
Payne's ( 1995 ) work, reported in Chap. 1 , provides several examples of how
S-R can influence the usability of interfaces. The better designs (shown in Chap. 1
and explained further in the exercises) show that better S-R reduces errors by about
70% compared to a poor mapping, and that response times can be up to 30%
higher with a poor mapping.
Another way to describe this aspect of behavior is making the task/action
mappings appropriate. That is, the task the user is trying to perform should be easy
to map to an action to perform. This is taken up in Chap. 12 as the Gulf of
Execution.
The effect of S-R compatibility can also play out in computer interface menus
and interfaces. If the user is searching for a widget, then an interface that explicitly
labels something as a widget is a clearer interface than one that calls the widgets
thingamajigs. Figure 6.5 shows an example where the phrase ''Frequent flyer
number'' was replaced with ''SkyMiles'' (a type of frequent flyer number). Making