Affordances, Visibility, and Constraints#

Note there is much confusion about the definition of affordances, and in Preece et al’s description they appear to make a common mistake. An affordance is, first and foremost, a possible way of interaction with something, whether or not you can perceive it. They describe it as a ‘clue’, which is misleading. Properly speaking, when an affordance (a way of interacting with something) is visible (perceived), only then is there a clue. Gaver’s paper linked below provides clarification.

Readings:

• Interaction Design - Preece, pg. 26-30, 1.7.3. Design Principles
• Technology Affordances – Gaver (https://www.lri.fr/~mbl/Stanford/CS477/papers/Gaver-CHI1991.pdf)

Questions#

1. List some of the affordances associated with the following items. Consider examples of different design variants where the affordances differ and are more or less perceived:

   • A towel
   • A joystick (as an interface to a digital system, when coupled with a GUI element such as a pointer – think of the ways a joystick can control a game)
   • A pop-up menu (GUI element)

2. The readings list the types of feedback available for interaction design as audio, tactile, verbal, and visual. Discuss an example of each feedback type, and how it is appropriate (or not) for the interaction scenario.