exercises

5. interaction design basics

EXERCISE 5.2

The exercises 5.2, 5.3, 5.4 and 5.5 are based around a nuclear reactor scenario on the web at: www.hcibook.com/e3/scenario/nuclear You will need to read the scenario in order to answer these exercises.

Comment on the user of colour in the Alarm Control, Emergency Shutdown and Emergency Confirm panels (figure CS.2)

answer available for tutors only

Red represents danger (cultural, but pretty universal), so good to represent alert state and for emergency shutdown and confirm button. Similarly, green represents safety. In UK and some countries green/amber/red also used for traffic lights, and alarm panel reflects this (recruiting real world knowledge). Red also good to grab attention and seems 'close' (visual perception and 3D vision), so good choice for making CONFIRM button obvious when it needs to be pressed.

However red/green colour blind users would have some problems. The alarm state indicator is fine as colour is a redundant cue and can simply use location, but perhaps a text label would help. The confirm button, however, fails completely as the only way of telling it needs to be pressed is the green to red colour change which would be invisible. Perhaps making it red and flashing would be better.

Other exercises in this chapter

ex.5.1 (tut), ex.5.2 (tut), ex.5.3 (tut), ex.5.4 (tut), ex.5.5 (tut), ex.5.6 (ans), ex.5.7 (tut), ex.5.8 (tut), ex.5.9 (tut), ex.5.10 (tut), ex.5.11 (tut), ex.5.12 (tut)

all exercises for this chapter