Eberts, R. (1994)
From Norman (1988):
"the perceived and actual properties
of the thing, primarily those fundamental properties that determine
just how the thing could possibly be used."
Affordances and constraints compliment good interface
metaphor design
Function and application of tools/artifacts self-evident
from affordance design
Comparison: chop sticks vs the fork
The typical GUI button depicts the same properties of
its real-world counterpart:
A raised surface
Shadows
Possibly sound
Constraints increase the power of affordances by reducing
potential error in operation
Real world constraints:
Scissors design
Computer peripheral adapters
GUI constraints:
Context-sensitive menus
Slider bars