Researchers Link Understanding Metaphors to Sensory Touch

When a girlfriend tells you she had a rough day, do you feel sandpaper under your fingers?

A recently released study finds your brain may be replaying sensory experiences to help understand common metaphors.

Psychologists and linguists have analyzed how much the brain mediates direct sensory experience in order to understand metaphors. Researchers found that our everyday speak is filled with metaphors, and some of these metaphors are so familiar, that they are now attached to our sensory and motor experiences.

New types of brain imaging reveal that the part of the brain that determines texture through touching is also activated when someone hears a sentence containing metaphors. This same region of the brain is not activated when a similar sentence is used that expresses actual meaning, as opposed to metaphors.

“We see that metaphors are engaging the ares of the cerebral cortex involved in sensory responses even though the metaphors are quite familiar,” said Krish Sathian, senior author of the study, in a statement. “This result illustrates how we draw upon sensory experiences to achieve understanding for metaphorical language.”

Seven college students were used for this study, and were asked to listen to sentences that had textural metaphors, and also to sentences that were matched for meaning and structure. They were then told to press a button as soon as they understood each sentence.

Blood flow in their brains was then monitored by MRI, and it was learned that on average, response to a sentence containing a metaphor took a bit longer (0.84 versus 0.63 seconds).

“Interestingly, visual cortical regions were not activated by textural metaphors, which fits with other evidence for the primacy of touch in texture perception,” said Simon Lacey, one of the co-authors of the study.

Other neurologists have also determined that injury to different parts of the brain can hinder a patients ability to understand metaphors. “I don’t think that there’s only one area responsible for metaphor processing,” said Sathian. “Actually, several recent lines of research indicate that engagement with abstract concepts is distributed around the brain.”

“I think our research highlights the role of neural networks, rather than a single area of the brain, in these processes,” Sathian continued. “What could be happening is that the brain is conducting an internal simulation as a way to understand the metaphor, and that’s why the regions associated with touch get involved.”