[Avery Andrews 930913.0944]
What Gibson really meant by `affordance' I wouldn't claim to know. But
here's a proposed PCT version of the concept: An affordance is a
reference level for a percept that an environment makes it realistic
for an organism to set for itself. E.g. if a landscape contains
smallish rocks, they afford throwing to humans and chimpanzees, but
not dogs, etc.
The concept combines contributions of the environment (the actual stuff),
plus of the organism (what it can perceive, what it can do) in what seems
to me to be an appropriate way, without being too hard to understand.
Avery.Andrews@anu.edu.au