Hemispheric differences for enhancement and suppression mechanisms during story comprehension

Area of Science:

• Cognitive Neuroscience
• Psycholinguistics
• Neuroscience of Language

Background:

• Readers track character goals in narratives, but the hemispheric mechanisms of goal enhancement and suppression are not well understood.
• Cerebral hemispheres may play distinct roles in processing dynamic information during text comprehension.

Purpose of the Study:

• To investigate the neural mechanisms of goal representation and updating in the left and right cerebral hemispheres during narrative comprehension.
• To determine if distinct enhancement and suppression processes occur in each hemisphere.

Main Methods:

• Participants read narrative texts with character goals.
• Goal-related information (repeated, new, or unrelated) followed initial goal presentation.
• Lexical decision task on original-goal targets presented to the left visual field (right hemisphere) or right visual field (left hemisphere).

Main Results:

• Greater facilitation for original goals in the right hemisphere when the goal was repeated.
• Reduced facilitation for original goals in the left hemisphere when a new goal was introduced.
• Evidence for separable enhancement (right hemisphere) and suppression (left hemisphere) mechanisms.

Conclusions:

• The findings suggest distinct hemispheric roles in narrative goal processing.
• The right hemisphere may be involved in maintaining or enhancing representations of established goals.
• The left hemisphere appears to play a role in suppressing outdated goals in favor of new ones.