Right Cerebral Hemisphere Activation of Perceptual Representations During Situation Model Construction.

Ethics number: 2011/198

Student Investigator: Evan Morris

Project Type: Honours

Supervisor: Dr Bethanie Gouldthorp

Recent evidence suggests that the right cerebral hemisphere (RH) may have a larger role than the left cerebral hemisphere (LH) in generating perceptual information during language comprehension. Hemispheric asymmetries were investigated in the activation of perceptual information during sentence comprehension using a divided visual-field paradigm. Thirty-one participants read sentences that implicitly implied the orientation of an object, before a horizontal or vertical picture that matched or mismatched the implied orientation was presented to the left visual-field (RH) or the right visual-field (LH). Response times (RTs) and accuracy of relatedness decisions made in respect of those targets were recorded. Significantly faster RTs in the match versus mismatch condition—a ‘mismatch effect’—revealed that participants inferred from world knowledge the orientation of an object, and were facilitated by pictures that matched and inhibited by pictures that mismatched the implied orientation. Evidence of a RH involvement in the activation of perceptual information was obtained through a significant mismatch effect, but only when vertical targets were displayed. Conversely, evidence of a LH contribution was obtained only when horizontal targets were displayed. The results partially support a significant role of the RH in the activation of perceptual representations during language comprehension. Furthermore, the results suggest that picture orientation is processed asymmetrically between the hemispheres. These findings provide an important contribution to the understanding of hemispheric language and picture orientation processing.