UC Riverside

The present study examined left (LH) and right (RH) hemisphere involvement in discourse processing by testing the ability of each hemisphere to use world knowledge in the form of script contexts for word recognition. Participants made lexical decisions to laterally presented target words preceded by centrally presented script primes (four sentences describing common situations). To examine the maintenance of script information across intervening text, there were six types of primes. These consisted of either single scripts or combinations of two different scripts: (1) a related script, (2) an unrelated script, (3) a related script+a neutral "filler," (4) a related script+an unrelated script, (5) an unrelated script+a related script, and (6) a neutral baseline condition. Results indicated that in the LH, only related scripts or related scripts preceded by unrelated scripts facilitated target word recognition. In contrast, the RH gained significant facilitation from all combinations of script primes, including related scripts followed by either filler materials or unrelated scripts. These results are consistent with the theory that the RH contributes in a critical way to discourse comprehension by maintaining widespread meaning activation for an extended period. This unique ability of the RH may be especially important for integrative processes needed to achieve global coherence during discourse processing.