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Differences in semantic category priming in the left and right cerebral hemispheres under automatic and controlled
1School of Psychology, Murdoch University, Perth, WA, Australia. collins@central.murdoch.edu.au
Neuropsychologia
|September 1, 1999
Summary
This study explored how each brain hemisphere processes semantic meanings. Both hemispheres show automatic access to semantic categories, but the right hemisphere is slower in accessing these meanings.
Area of Science:
- Cognitive Neuroscience
- Psycholinguistics
- Hemispheric Specialization
Background:
- Understanding semantic category meaning generation is crucial for cognitive neuroscience.
- Investigating the distinct roles of the left and right cerebral hemispheres in language processing remains a key research area.
- Differentiating between automatic and strategic processing levels provides insight into cognitive mechanisms.
Purpose of the Study:
- To investigate the contribution of each cerebral hemisphere to semantic category meaning generation.
- To examine how automatic and strategic processing levels influence hemispheric contributions.
- To compare the time course of semantic activation between the left and right hemispheres.
Main Methods:
- A priming experiment using a lexical decision task with word pairs presented to the left or right visual fields (LVF/RVF).
- Two conditions were employed: one designed for automatic processing (250 ms stimulus onset asynchrony, 20% related pairs) and one for controlled processing (750 ms SOA, 50% related pairs).
- Prime words were independently projected to either visual field, followed by target words, measuring response facilitation.
Main Results:
- In the automatic processing condition, primes facilitated responses to targets in the right visual field (RVF).
- In the controlled processing condition, primes facilitated responses to targets in the left visual field (LVF).
- Facilitation effects suggested automatic processes in both conditions, with strategic processes evident in the left hemisphere during controlled processing.
Conclusions:
- Both cerebral hemispheres possess automatic access to semantic category meanings.
- The time course for activating semantic category meanings is slower in the right hemisphere compared to the left.
- Hemispheric specialization influences the engagement of strategic processing, with the left hemisphere showing greater involvement.