Message-level processing of contextual information in the right cerebral hemisphere.

Recent research into right hemisphere (RH) sentence comprehension has produced a number of inconsistent results, particularly in relation to the types of processing used. The present study investigated whether the RH utilizes message-level mechanisms during sentence comprehension and whether it benefits from additional contextual information that is not the result of simple word-level associations. Thirty-six right-handed Murdoch University undergraduate psychology students participated in a computer-based lexical decision task where reaction time and error rates were recorded. Normal and scrambled versions of sentences with high, low, and neutral levels of constraint were presented centrally, with the sentence-final word presented to either the left or right visual field. The results demonstrated that the RH was facilitated by increases in context to at least the same extent as the left hemisphere (LH) and, furthermore, that this was not simply due to increased word-level associations. These findings are in contrast to previous behavioral research that suggests the RH is less sensitive to message-level processing than the LH.