Learning to perceive the affordance for long-distance throwing: smart mechanism or function learning?

Bingham, Schmidt, & Rosenblum, (1989) showed that people are able to select, by hefting balls, the optimal weight for each size ball to be thrown farthest. We now investigate function learning and smart mechanisms as hypotheses about how this affordance is perceived. Twenty-four unskilled adult throwers learned to throw by practicing with a subset of balls that would only allow acquisition of the ability to perceive the affordance if hefting acts as a smart mechanism to provide access to a single information variable that specifies the affordance. Participants hefted 48 balls of different sizes and weights and judged throwability. Then, participants, assigned to one of four groups, practiced throwing (three groups with vision and one without) for a month using different subsets of balls. Finally, hefting and throwing were tested again with all the balls. The results showed: (1) inability to detect throwability before practice, (2) throwing improved with practice, and (3) participants learned to perceive the affordance, but only with visual feedback. These results indicated that the affordance is perceived using a smart mechanism acquired while learning to throw.