Tracking the time course of action priming on object recognition: evidence for fast and slow influences of action on perception.

Perception and action are classically thought to be supported by functionally and neuroanatomically distinct mechanisms. However, recent behavioral studies using an action priming paradigm challenged this view and showed that action representations can facilitate object recognition. This study determined whether action representations influence object recognition during early visual processing stages, that is, within the first 150 msec. To this end, the time course of brain activation underlying such action priming effects was examined by recording ERPs. Subjects were sequentially presented with two manipulable objects (e.g., tools), which had to be named. In the congruent condition, both objects afforded similar actions, whereas dissimilar actions were afforded in the incongruent condition. In order to test the influence of the prime modality on action priming, the first object (prime) was presented either as picture or as word. We found an ERP effect of action priming over the central scalp as early as 100 msec after target onset for pictorial, but not for verbal primes. A later action priming effect on the N400 ERP component known to index semantic integration processes was obtained for both picture and word primes. The early effect was generated in a fronto-parietal motor network, whereas the late effect reflected activity in anterior temporal areas. The present results indicate that action priming influences object recognition through both fast and slow pathways: Action priming affects rapid visuomotor processes only when elicited by pictorial prime stimuli. However, it also modulates comparably slow conceptual integration processes independent of the prime modality.