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3.5 Informing design: from theory to practice 101

Figure 3.13 Information
visualization. Visual In-
sights' site map showing
web page use. Each page
appears as a 3D color rod
and is positioned radially,
with the position showing
the location of the page in
the site.

gramming bugs). In so doing, they can extend or amplify cognition, allowing people
to perceive and do activities that they couldn't do otherwise. For example, a num-
ber of information visualizations have been developed that present masses of data
in a form that makes it possible to make cross comparisons between dimensions at
a glance (see Figure 3.13). GUIs can also be designed to reduce memory load sig-
nificantly, enabling users to rely more on external representations to guide them
through their interactions.

3.5 Informing design: from theory to practice
Theories, models, and conceptual frameworks provide abstractions for thinking
about phenomena. In particular, they enable generalizations to be made about cog-
nition across different situations. For example, the concept of mental models pro-
vides a means of explaining why and how people interact with interactive products
in the way they do across a range of situations. The information processing model
has been used to predict the usability of a range of different interfaces.
Theory in its pure form, however, can be difficult to digest. The arcane terminol-
ogy and jargon used can be quite off-putting to those not familiar with it. It also re-
quires much time to become familiar with it-something that designers and engineers
can't afford when working to meet deadlines. Researchers have tried to help out by
making theory more accessible and practical. This has included translating it into:
design principles and concepts
design rules
analytic methods
design and evaluation methods