Task constraints on affordance boundaries.

The actualization of a simple affordance task-grasping and moving wooden planks of different sizes using either one or two hands-was assessed in the context of task-relevant (plank sequence, plank presentation speed) and task-irrelevant (cognitive load) manipulations. In Experiment 1, fast (3 s/plank) and self-paced ( approximately 5 s/plank) presentation speeds revealed hysteresis; the transition point for ascending series was greater than the transition point for descending series. Hysteresis was eliminated in the slowest presentation speed (10 s/plank). In Experiment 2, hysteresis was exaggerated by a cognitive load (counting backward by seven) for both fast and slow presentation speeds. These results suggest that behavioral responses to the attractor dynamics of perceived affordances are processes that require minimal cognitive resources.