Having a tough time at work? Been trying to sort out a thorny problem, or push through a hard training program? For most of us, these are questions we understand instinctively – so much so that we don’t even notice the metaphorical language being used. But for people born without somatosensation – the ability to feel touch, pain, pressure, temperature, and proprioception – those normal phrases were previously believed to be essentially incomprehensible.
A new research paper, however, suggests that assumption may have been wrong – and it’s all thanks to a single, maybe literally one-of-a-kind, study participant.
“Kim is a gift,” Lenore Grenoble, a professor in the University of Chicago’s Department of Linguistics and co-author of the paper, said in a statement. “We can test things with her that we can't possibly test otherwise.”
Kim, who is known in the study only by her first name, was born without somatosensation – she lacks the sensory nerve fibers that allow her to feel her own body. That makes her incredibly interesting from a neurobiological standpoint: “She's just never had it and that's unique,” Grenoble explained. “It may be a case study of just one, but it's a pretty powerful one.”
It means that, for the first time, the researchers were able to fill in the blanks when it comes to how humans perceive metaphors based on experience. We already know, for example, that blind or colorblind people can understand phrases like “green with envy” or “feeling blue”, and that deaf or hearing-impaired people know what it means for a pattern or color to be “loud” – but when it comes to somatosensation-based speech, there simply haven’t been enough test subjects like Kim for researchers to test their ideas.
“Everyone has had some of this [somatosensation] experience,” Grenoble pointed out. “Some people have lost it, but they have a memory of it to draw on.”
But with Kim, the situation is very different. While researchers like Grenoble long supposed that we interpret somatosensation metaphors based on our experiences with those physical feelings, Kim’s performance in a multiple-choice vocabulary quiz has shown that, at the very least, that’s not the only way to understand these turns of phrase.
“Phrases like ‘driving a hard bargain’ are extensions of words that have a very sensory root,” said Peggy Mason, a University of Chicago Professor of Neurobiology and first author of the paper. A specialist in empathy and other pro-social behaviors, Mason has been working with Kim since 2014 to investigate just how different her experience of the world, and language, is from the norm.
And the answer to that, it appears, is “not so different after all.” Over 80 test questions featuring short vignettes described by either tactile or non-sensory-based idioms, Kim performed as well or better than two control groups at identifying the correct expressions for the situation.
“Since Kim has no somatosensation, we really wondered how she would deal with this,” Mason explained. “But we see that while sensory experiences could be very important to many people, it's not required. You can learn this too.”
Instead of intuiting meaning through experience, it seems Kim is drawing on linguistic definitions based on information from others: “I think pretty literally about words,” she said, “especially words about, like you know, sensation and things like that.” It’s not a foolproof system – the paper notes that Kim initially assumed grits, the food, must be gritty in texture because of the name – but it’s a crucial clue in the question of how we understand sense-based metaphors.
“Now we have data to show which side of the debate is correct,” Grenoble said. “You don't have to have somatosensory experience. That opens gateways to really understanding how these things are acquired, how they change, and how they're used for all kinds of things.”
“I actually think that most people learn it through association, because they are metaphors,” she added. “They aren't literal meanings, so, you have to understand how to interpret the metaphor.”
“[But] what Kim is really showing us is that you're interpreting it linguistically, because she's got nothing else.”
The paper is published in Frontiers in Communication.