In addition to the concept of phrase, virtually all syntactic theories postulate the existence of syntactic transformations that allow a phrase to be moved away from its initial position. For example, in the sentence "Here's the letter carrier the dog bit", the object "the letter carrier" has moved away from its initial position, the object of the verb bite. Linguists assume that the displaced phrase leaves a kind of pointer (trace orgap) at its starting point.
The cross-modal priming technique was used by David Swinney to demonstrate the psychological reality of the trace concept. While listening to a spoken sentence, at the moment of the trace (here, after "bitten"), we observe the priming of a visually presented word linked to the antecedent of the trace (in our example, the word "letter carrier" would prime a word like "mail"). There would thus be an internal reactivation of the antecedent, caused by the trace.
Linguists distinguish between different types of syntactic movement, such aswh-movement for the formation of questions, relatives or topicalization;verb-to-C movement; andA-movement used in inaccusative verbs. Naama Friedmann's studies on the acquisition of these structures in children and on the errors of agrammatic patients confirm that these different movements call on distinct hierarchical levels of the syntactic tree. Neuroimaging confirms that syntactic movement once again involves the "syntactic core" formed by the pSTS and IFGtri regions.
