Week 4: Affordance

Affordance: An affordance is a quality of an object, or an environment which allows an individual to perform an action.

Properties:
1. exists relative to the action capabilities of a particular actor
2. it's existance is independent of the actor's ability to perceived it
3. an affordance does not change as the needs/goals of the actor change

The point of affordance is when it's taken advantage of, the user knows what to do just by looking at it; no picture, label or instruction needed.

Affordances in Novel Objects
How do you turn on the shower? - through trial and error


Affordance is GUI
- Important concept
- Buttons in 3D shapes apper to "sticks out" and afford pushing
- Sliders and scroll bars afford pushing

Perceived Affordance
- Coined by Donald Norman
- More interested in what user perceives than what is actually true

Elements of Perceived Affordance:
Context - where
Culture - society
Instinct - unconscious
Mental Models - expectations

Designing with Intent - designing specific affordances and constraint to guide users
Guidiing Users = shaping perceptions of what actions are possible and making some actions intentionally more diffcult / impossible

Forcing Functions:
1. Lock-In: A system arranged such that the process is kept active
2. Lock-Out: May be implemented as extra step
3. Interlock: Combines elements of lock-in and lock-out, most common forcing function mechanism, the ability to use a function depends in another running/being started or some other condition being fulfilled.

Affordance Manipulation - Manipulating to suit their own needs.
eg: cone shaped cup - throws it away right after drinking because it cannot stand - library

Summary:
All designs is persuasive
Profitable to the client = profitable to the user
Persuasive technology??