ABSTRACT
A strategy based on a constant value of the optical variable tau, the inverse of the rate of dilation of the optic image of an approaching object. The literature suggests the possibility of an intensity-coupling principle in interceptive tasks. When the velocity of approach is low, a co-variation of movement velocity and initiation time is observed; when it is high, movement velocity and initiation time are roughly constant. The present experiment was aimed at exploring the intensity coupling phenomenon in conditions in which the movement towards the ball was either executed or simply triggered by the actor. The Phenomenon was observed in several tasks in which action intensity was essentially task-irrelevant, notably in the three pendulum-release tasks. Moreover, when the very definition of the task implied that the variations of time-to-contact at initiation time be minimized, intensity coupling was still observed.
