Creator of Affordances - James Jerome Gibson
The concept of an affordance was coined by the perceptual American psychologist, J.J. Gibson (1904-1979). Gibson defined an "affordance" as the quality of an object, or an environment, that allows an individual to perform an action. According to his theory, perception of the environment inevitably leads to some course of action. Affordances, or clues in the environment that indicate possibilities for action, are perceived in a direct, immediate way with no sensory processing. Examples include: buttons for pushing, knobs for turning, handles for pulling, levers for sliding, etc.
Gibson’s affordance is independent of the actor's ability to perceive it. A door can have the affordance of 'open-ability' (its affordance relative to the actor) but can be hidden, camouflaged or likewise (the information specifying its affordance are not available to the actor). On the other hand, when both the affordance (the door can be opened by the actor) and the information in the environment that specifies the affordance (the door is visible, has a handle etc.) are present, a state of direct perception is reached. The environment thus affords many potential actions to the active observer. For Gibson, the affordance resides outside the observer; it is in the environment, but only potentially, for it depends on the relationship between the environment and an active observer.
Gibson's Affordances
- Action possibilities in the environment in relation to the action capabilities of an actor
- Independent of the actor's experience, knowledge, culture, or ability to perceive
- Existence is binary - an affordance exists or it does not exist.
PERCEIVED AFFORDANCE
In design, designer care much more about what the user perceives than what is actually true, whether the user perceives that some action is possible.
· In product design, physical objects can be both real and perceived affordances, and the two need not be the same.
· In graphical, screen-based interfaces, all that the designer has available is control over perceived affordances.
The computer system, affords pointing, touching, looking, and clicking on every pixel of the display screen. Most of this affordance is of no value. Thus, if the display does not have a touch-sensitive screen, the screen still affords touching, but it has no result on the computer system.
However, the affordance still has impact: it is useful in multiple-person communication, and it helps aid the sale of screen-cleaning tissues and fluids. All screens afford touching: only some detect the touch and are capable of responding. But the affordance of touch-ability is the same in all cases. Touch sensitive screens often make their affordance visibly perceivable by displaying a cursor under the pointing spot. The cursor is not an affordance; it is visual feedback.
Consequently:
1. All design is persuasive.
2. Profitable to the client.
3. Persuasive technology is about persuading, although they aim to make more money.
4. The world needs persuasive technology.
http://www.jnd.org/dn.mss/affordances_and_design.
http://www.newworldencyclopedia.org/entry/J._J._Gibson#Affordances
http://www.interaction-design.org/encyclopedia/affordances.html
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