It’s forgivable if you think that speech is just words, what with all the texts and emails that ping on our devices and all the chitchat made with friends and colleagues. But according to a fascinating branch of psychology, the gesticulations we make in conversation are part of how we talk. “Gesticulation isn’t divorced from speech. It’s completely tied to your speech,” University of Chicago psychologist Susan Goldin-Meadow, one of the leading researchers in the field, told Science of Us in July. “It’s part of your cognition. It’s not just mindless hand-waving.”
What might be even more intriguing is that blind people — even those blind from birth — gesture like sighted people; it’s not a matter of learning to gesture by seeing other people do it. And according to a new study that Goldin-Meadow co-authored, people gesture in accordance with their native language.
For the new study, Goldin-Meadow and her colleagues brought in blind native Turkish speakers and native English speakers, as well as sighted Turkish and English native speakers. Turkish and English are perfect languages for investigating this, points out linguistics blogger Lauren Gawne, since the two languages have been consistently associated with different styles of gesturing. “English speakers will be more likely to show the manner (e.g. ‘rolling’ or ‘bouncing’) and trajectory (e.g. ‘left to right,’ ‘downward’) together in one gesture, and Turkish speakers will show these features as two separate gestures,” Gawne writes. “This reflects the fact that English ‘roll down’ is one verbal clause, while in Turkish the equivalent would be yuvarlanarak iniyor, which translates as two verbs ‘rolling descending.’” Hand motions are choreographed by grammatical structure, you might say.
The center of the new study was an experiment where participants investigated 12 tabletop scenes where a doll was put into various “motion events,” like climbing into a tree house, flipping over a beam, or running away from a motorcycle. Blind participants investigated with their hands, as did a group of sighted speakers of either language wearing blindfolds. A third group of sighted speakers inspected the scenes visually. They were then videotaped describing the scenes.
As predicted, the Turkish speakers — blind and sighted alike — used more separated sentence gestures than the English speakers, consistent with the structure of their native tongues. It’s evidence of how languages package speech and gesture for blind and sighted people alike, the authors say. “Our findings thus underscore the tight link between speech and gesture, and identify speech as the source of the cross-linguistic variation observed in gesture,” they write. “Blind speakers learn language-specific gestures by learning to speak the language, not by watching others move.” Language shapes not just how we think, but how we move.