Sentence context and lexical ambiguity resolution by the two hemispheres

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psycholinguistics

Background:

• Lexical ambiguity resolution is crucial for language comprehension.
• Hemispheric asymmetries in cognitive functions are well-documented.
• Understanding the neural basis of word meaning selection is an ongoing research area.

Purpose of the Study:

• To investigate hemisphere-specific roles in resolving lexical ambiguity within sentence contexts.
• To determine if the left and right cerebral hemispheres process ambiguous words differently.
• To explore the contribution of each hemisphere to selecting contextually appropriate word meanings.

Main Methods:

• A lexical decision task was employed.
• Participants responded to lateralized targets following sentence-final ambiguous words.
• Stimuli varied in semantic relatedness to congruent or incongruent word meanings and sentence bias.

Main Results:

• The right visual field (RVF), associated with the left hemisphere, showed facilitation for sentence-congruent targets, indicating efficient meaning selection.
• The left visual field (LVF), associated with the right hemisphere, facilitated targets related to ambiguous word meanings irrespective of sentence context.
• Incongruent targets were not facilitated in the RVF, suggesting a lack of sustained access to non-contextual meanings.

Conclusions:

• The left hemisphere is critical for selecting the contextually appropriate meaning of ambiguous words.
• The right hemisphere appears to play a role in maintaining multiple, potentially non-contextual, word senses.
• These findings highlight distinct, complementary roles for each hemisphere in resolving lexical ambiguity.