Pantomimes facilitate verbs (but not nouns) comprehension

Recently evidence was found that the motor representation of the body is involved in conceptual knowledge processing. Specifically, iconic gestures and pantomimes are characterized by a certain degree of isomorphism between the shape of the gesture and the entity that is expressed by the gesture. This isomorphism is maximum when the iconic gesture represents an action. Thanks to this close relation, we hypothesized that the iconic gestures would differently modulate the processing of action-verbs and object-nouns. We investigated the relation between iconic gestures and words using a priming paradigm. Participants watched a short videoclip with an iconic gesture followed by an object-noun or an action-verb. The meaning of the gesture and the word could be the same or different. The task was to create a mental image of the word. We recorded the time to form the mental image (RT), and event related potentials (ERP) synchronized with the presentation of the word. The main result showed that watching an iconic gesture with the same meaning facilitates the process to form a mental image of a given word, and therefore the process to access the meaning of the word. Moreover, electrophysiological data (N400 component) showed that this facilitatory effect was greater for action-verbs then for object-nouns. The results are discussed in the context of the semantic relations between gestures and words.