“Figurative language may be more effective in communication and may facilitate processes such as affiliation, persuasion, and support,” Citron says. “Further, as a reader or listener, one should be wary of being overly influenced by metaphorical language.”
Colloquially, metaphors seem to be employed precisely to evoke an emotional reaction, yet the actual emotional effect of figurative phrases on the person hearing them has not before been deeply explored, says Benjamin Bergen, an associate professor of cognitive science at the University of California, San Diego, who studies language comprehension, and metaphorical language and thought.
“There’s a lot of research on the conceptual effects of metaphors, such as how they allow people to think about new or abstract concepts in terms of concrete things they’re familiar with. But there’s very little work on the emotional impact of metaphor,” says Bergen, who had no role in the research but is familiar with it.
“Emotional impact seems to be one of the main reasons people use metaphors to begin with. For instance, a senator might describe a bill as ‘job-killing’ to evoke an emotional reaction,” he says. “These results suggest that using certain metaphorical expressions induces more of an emotional reaction than saying the same thing literally. Those expressions that have this property are likely to have the effects on reasoning, inference, judgment, and decision-making that emotion is known to have.”
The brain areas that taste-related words did not stimulate are also an important outcome of the study, Citron says. Existing research on metaphors and neural processing has shown that figurative language generally requires more brainpower than literal language, Citron and Goldberg write. But these bursts of neural activity have been related to higher-order processing from thinking through an unfamiliar metaphor.
The brain activity Citron and Goldberg observed did not correlate with this process. In order to create the metaphorical- and literal-sentence stimuli, they had a group of people separate from the study participants rate sentences for familiarity, apparent arousal, imageability—which is how easily a phrase can be imagined in the reader’s mind—and how positive or negative each sentence was interpreted as being.
The metaphorical and literal sentences were equal on all of these factors. In addition, each metaphorical phrase and its literal counterpart were rated as being highly similar in meaning.
These steps helped to ensure that the metaphorical and literal sentences were equally as easy to comprehend. Thus, the brain activity the researchers recorded was not likely to be in response to any additional difficulty study participants had in understanding the metaphors.
“It is important to rule out possible effects of familiarity, since less familiar items may require more processing resources to be understood and elicit enhanced brain responses in several brain regions,” Citron says.
Citron and Goldberg plan to follow up on their results by examining if figurative language is remembered more accurately than literal language, if metaphors are more physically stimulating, and if metaphors related to other senses also provoke an emotional response from the brain.
An Einstein Visiting Fellowship from the Einstein Foundation in Berlin supported the work.