Backward Priming and Postlexical Processing in the Right Hemisphere

Abstract

Postlexical processing in the intact cerebral hemispheres was studied using a divided visual field method. Asymmetrically associated prime-target pairs were presented in forward (PRIEST-MAN) and backward (MAN-PRIEST) directions in a binary lexical decision task. The primes were presented either centrally or laterally, and the targets laterally. The priming effects in the backward conditions were assumed to reflect postlexical semantic processing. The analyses of response times revealed that, in the left visual field, backward priming was equal in both prime conditions, but forward priming was observed for the central primes only. In the right visual field, forward priming was similar in both prime conditions, whereas backward priming was restricted to the central prime condition. The analyses of errors showed an LVF advantage in backward priming and a trend towards an RVF advantage in forward priming in central prime conditions. The results suggest that the right hemisphere is capable of postlexical semantic processing, but may lack an expectancy-based mechanism underlying forward priming.