Evidence for visuomotor priming effect
‘WHILE seated, the patient took a glass, gave it to the examiner and then picked up a jug. He poured water into the glass and, having put down the jug, took the glass …’. This compulsive behaviour, described by Lhermitte in patients with frontal lobe lesions, is an example of how, without any internal motivation, visual stimuli may impel a patient to act and ‘grasp the objects presented and use them’. We investigated whether this behaviour is a pathological manifestation of a normal, automatic object to action transformation. To test this, we primed normal subjects, while ready to execute a grasping movement, by visually presenting them with drawings irrelevant to the task to be executed. Drawings visually congruent with the object to be grasped markedly reduced the reaction time for grasping. These data represent the first evidence for the existence of a visuomotor priming. Seeing an object facilitates an action congruent with the visual properties of that object.