7. design rules


(a) Why are there few effective HCI standards?

(b) How do "golden rules" and heuristics help interface designers take account of cognitive psychology? Illustrate your answer with examples.

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(a) Because standards require solid and agreed upon underlying theory and, being a relatively new discipline, HCI is lacking this theory. Most HCI standards relate to more ergonomic issues (layout design, etc.) where the theory is more clearly established. However, most of the challenges to interaction involve much higher level cognitive demands of the interface, and here we do not have empirical results on cognition and interaction that would result in prescriptive standards. Our theories are improving, but we are a long way from being able to speak with the authority of standards.

(b) Golden rules and heuristics encapsulate psychological theory in design-oriented rules so that designers can apply them directly to design situations. It is necessary to be familiar with the underlying theory so that they are applied within comparable contexts but good guidelines indicate this to enable designers to select them appropriately. A simple example would be the guideline 'group related items together in menu structures', which is based upon the theory of recall being aided by the cue of categorisation. Another good example is use of visible modes so that a user will more likely be able to predict the interpretation of a given action at any time.

Other exercises in this chapter

ex.7.1 (ans), ex.7.2 (ans), ex.7.3 (open), ex.7.4 (ans), ex.7.5 (ans), ex.7.6 (ans), ex.7.7 (tut), ex.7.8 (tut), ex.7.9 (open), ex.7.10 (tut), ex.7.11 (tut), ex.7.12 (tut), ex.7.13 (tut)

all exercises for this chapter