Psychology: Sweet Discovery

She’s a sweet girl. He peppered her with questions. She stayed to the bitter end. We use metaphors that engage the taste buds so often we barely think of them as figurative. “When you talk about abstract ideas, you can’t help but use metaphorical language,” says psychology professor Adele Goldberg. “Pick a topic — love, anger, anything — and you start to talk using words from a more concrete domain.”

Among linguists like Goldberg, there is an ongoing debate about how people make meaning out of such words. Are they just symbols that stand in for more literal substitutes or — as some research has suggested — do people implicitly imagine the physical sensation behind the metaphor as they use them? To investigate this question, Goldberg recently used a brain scanner to figure out how subjects processed such phrases. She found that, indeed, people engaged the regions of the brain involved in taste when they encountered a tasty metaphor. 

But she and her co-researcher Francesca Citron, a neuroscientist at Lancaster University in England, also found something they didn’t expect: that metaphors engage the part of the brain involving emotional processing as well. “Since literal ways exist to say something, it’s interesting to ask, why do we even use metaphors?” Goldberg says. “The emotional engagement provides some of that answer.”

For their experiment, which took place at the Freie Universität in Berlin, Goldberg and Citron had native German speakers lie in an fMRI scanner while they were read sets of sentences. Some contained taste metaphors, such as “She treated him sweetly.” Others substituted a more literal word: “She treated him kindly.” When the listeners encountered the metaphors, the parts of the brain collectively known as the gustatory cortices lit up — the same parts activated when tasting a meal — suggesting that the listeners were using their sense of taste to make meaning of the words.

In addition, Goldberg and Citron saw activation in the amygdala, a part of the brain sometimes associated with fear, but which actually is involved in a wide range of emotional experiences. The finding, while unexpected, makes intuitive sense, Goldberg says: “Part of the reason we rely on this language may be that it is just more evocative.”

Over the past year, Goldberg and Citron have looked beyond taste to examine the effects of metaphors on the brain — for example, a bad day versus a rough day, or a good argument versus a strong argument. They found that in these cases as well, the metaphors elicited a response in the amygdala, as their literal counterparts did. 

Interestingly, the subjects of these experiments didn’t consciously find the sentences more emotional — the greater emotional engagement was only evident by looking at the brain activity. By using neuroimaging to examine exactly what is going on in people’s minds when they hear metaphorical language, the research helps explain the underlying science behind what poets and orators have known intuitively for centuries. “There is just something more engaging in saying, ‘she smiled sweetly at him,’ rather than ‘she smiled kindly,’ ” says Goldberg. “It could be connected to the fact that your physical experiences are more involved in the processing.”