Timing of grip and goal activation during action perception: a priming study

Several models of action recognition acknowledge the involvement of distinct grip and goal representations in the processing of others' actions. Yet, their functional role and temporal organization are still debated. The present priming study aimed at evaluating the relative timing of grip and goal activation during the processing of photographs of object-directed actions. Action could be correct or incorrect owing to grip and/or goal violations. Twenty-eight (Experiment 1) and 25 (Experiment 2) healthy adults judged the correctness of target actions according to object typical use. Target pictures were primed by action pictures sharing the same grip or same goal, both the same grip and same goal or none. Primes were presented for 66 or 300 ms in Experiment 1 and for 120 or 220 ms in Experiment 2. In Experiment 1, facilitative priming effects were observed for goal and grip similarity after 300 ms primes but only for goal after 66 ms primes. In Experiment 2, facilitative priming effects were found for both goal and grip similarity from 120 ms of prime processing. In addition, results from a control condition in Experiment 2 indicated that mere object priming could partially account for goal similarity priming effects, suggesting that object identity may help the observer to make predictions about possible action goals. Findings demonstrate an early and first activation of goal representations, as compared to grip representations, in action decoding, consistent with predictive accounts of action understanding. Future studies should determine to what extent the timing of grip and goal activation is context-sensitive.