Do motor representations influence declarative memory for graspable objects? A test with action priming and short-term hand nonuse.

This study addressed the role of motor representations in declarative memory (i.e., semantic and episodic). Based on embodied and grounded theories of cognition, it is often suggested that motor representations contribute to declarative memory. According to the action priming effect, graspable objects are categorised faster when primed by pictures of a congruent hand grip, as motor representations (how to grasp it) and semantic information (what it is) are closely related. Moreover, motor representations may contribute to episodic memory functioning. We immobilised participants' dominant hand for 24 hr to impair their processing of hand-related motor representations. This method is known to elicit rapid updating of cortical hand representations, and a slowdown in cognitive tasks linked to hand-related motor cognition. We expected to observe a decreased action priming effect following short-term hand nonuse. We further predicted that in a subsequent recognition task, objects that had been encoded following congruent action priming would be recognised faster by controls, but not by previously immobilised participants. Results did not show any effect of hand nonuse on action priming, suggesting that motor representations are not a decisive factor for this effect. Nonetheless, prime congruence influenced subsequent recognition. Immobilised participants were slower to recognise objects previously seen with an unrelated hand grip prime compared with a congruent one. This result suggests a contribution of motor representation to declarative memory, in particular when the sensorimotor system has previously been impaired.