How do illusions constrain goal-directed movement: perceptual and visuomotor influences on speed/accuracy trade-off.

Recent research shows that visual processing influences the speed/accuracy trade-off people use when performing goal-directed movement. This raises the question of how this influence is produced in visual cognition. Visual influences on speed/accuracy trade-off could be produced in conscious visual perception, in non-conscious visuomotor transformation, or by some interaction of conscious perceptual and non-conscious visuomotor processes. There is independent evidence showing that both perceptual and visuomotor processes are involved in trading off speed and accuracy; however, the interaction between these processes has yet to be investigated. We present an experiment in which we show that a change in visual consciousness induced by a perceptual illusion affects the speed and accuracy of goal-directed movements, suggesting that perceptual and visuomotor processes do interact in speed/accuracy trade-off. We discuss the consequences of these results for theories of visual function more generally.