May 11, 2012
Linguists and psychologists have debated how much the parts of the brain that mediate direct sensory experience are involved in understanding metaphors.
According to recent research at Emory, brain imaging studies reveals that a region of the brain important for sensing texture through touch, the parietal operculum, is also activated when someone listens to a sentence with a textural metaphor. The same region is not activated when a similar sentence expressing the meaning of the metaphor is heard.
The results were published online in the journal Brain & Language.
The research suggest, for instance, that when a friend tells you she had a rough day, and you feel sandpaper under your fingers, the brain may be replaying sensory experiences to help understand common metaphors.
The findings are in line with the thinking of previous researchers, who also argued that metaphor comprehension is grounded in our sensory and motor experiences.
“We see that metaphors are engaging the areas of the cerebral cortex involved in sensory responses even though the metaphors are quite familiar,” said senior study author Krish Sathian, a professor of neurology, rehabilitation medicine, and psychology at Emory. “This result illustrates how we draw upon sensory experiences to achieve understanding of metaphorical language.”
During the study, 7 college students were asked to listen to sentences containing textural metaphors as well as sentences that were matched for meaning and structure, and to press a button as soon as they understood each sentence. Blood flow in their brains was monitored by functional magnetic resonance imaging. On average, responses to a sentence containing a metaphor took slightly longer.
In a previous study, the researchers had already mapped out, for each of these individuals, which parts of the students’ brains were involved in processing actual textures by touch and sight. This allowed them to establish with confidence the link within the brain between metaphors involving texture and the sensory experience of texture itself.
“Interestingly, visual cortical regions were not activated by textural metaphors, which fits with other evidence for the primacy of touch in texture perception,” said research associate Simon Lacey, the paper’s first author.
In future research, Sathian plans to look into whether similar relationships exist for other senses, such as vision. The researchers also plan to probe whether magnetic stimulation of the brain in regions associated with sensory experience can interfere with understanding metaphors.
To read the entire story, click here: http://news.emory.edu/stories/2012/02/metaphor_brain_imaging/