Hemispheric processing in conventional metaphor comprehension: The role of general knowledge.

This study explored the relation between general knowledge and the hemispheric processing of metaphoric expressions in college age students. We hypothesized that prior knowledge influences how the hemispheres process metaphors in these individuals. In this study, 97 young (college-aged) adults completed a general knowledge and vocabulary test, and were then divided into high-knowledge/high-vocabulary and low-knowledge/low-vocabulary groups. Next, participants viewed word pairs consisting of conventional metaphors, novel metaphors, word pairs with a literal meaning, and unrelated word pairs. The first word in each pair was presented centrally, and the second was presented to the right visual field-left hemisphere (rvf-LH) or the left visual field-right hemisphere (lvf-RH), and participants indicated whether each pair was a meaningful expression. Accuracy results showed an interaction between general knowledge and visual-field hemisphere. Low-knowledge participants were more accurate for metaphors presented to the rvf-LH than the lvf-RH, whereas high-knowledge participants showed no accuracy differences between the hemispheres. We also found an interaction between vocabulary and visual field-hemisphere for conventional metaphors. Specifically, low-vocabulary participants showed a left-hemisphere accuracy advantage, but high-vocabulary participants showed similar accuracy patterns in both hemispheres. These results suggest that young adult readers who have more general knowledge process conventional metaphors similarly in both hemispheres, whereas young adult readers who have less general knowledge may rely more heavily on left-hemisphere processes during conventional metaphor comprehension.

Hemispheric processing of mental representations during text comprehension: evidence for inhibition of inconsistent shape information.

To successfully understand a text, readers often mentally represent the shape of an object described in a text (e.g., creating a mental image of a sliced tomato when reading about a tomato on a pizza). However, it is currently unclear how the cerebral hemispheres contribute to these mental images during reading. In the current study, participants were presented with sentences consistent with the shape of an object (i.e., the match condition), sentences inconsistent with the shape of an object (i.e., the mismatch condition), or sentences that did not specify the shape of an object (i.e., the neutral condition). Participants read each sentence and then viewed an image of an object that was quickly presented to either the right visual field-left hemisphere (rvf-LH) or the left visual field-right hemisphere (lvf-RH). Results indicate that when the shape of an object was implicitly described in the text (in Experiment 1), response times for images presented to the rvf-LH were longer in the mismatch condition than in the neutral or match conditions. However, no response time differences were evident in the lvf-RH. When the shape of an object was explicitly described in the text (in Experiment 2), response times were longer in the mismatch condition than in the neutral and match conditions in both hemispheres. Thus, hemispheric involvement in mental representation depends on how explicit information is described in a text. Furthermore, these findings suggest that readers inhibit information that does not match an object׳s shape described in a text.