A study of hand gesturing has found that it is not done to impart information, nor it is performed to mimic others, but hand movements are as much a part of talking as moving your lips.
"Gestures are produced by speakers from all cultural and linguistic backgrounds and emerge in young children even before the development of language," say Jana Iverson and Susan Goldin-Meadow in the journal Nature.
The two researchers, from Indiana University and the University of Chicago, investigated hand gesturing in 12 young people who had been blind since birth to test whether hand movements were learnt from others. "Individuals who are blind from birth never see such gestures and so have no model for gesturing," they say.
"But here we show that congenitally blind speakers gesture despite their lack of a visual model."
The study found that all the blind children and adolescents in the study used hand gestures during talking and they did it at a similar rate to a comparable group of youngsters who were not blind.
All of the blind speakers also used a similar set of gestures to those used by sighted people, indicating that hand movements are not necessarily learnt by watching other speakers.
"For example both blind and sighted speakers tilted a C-shaped hand in the air as though pouring liquid from a glass to indicate that a liquid had been transferred to a different container," the researchers say.
A second possible reason for hand gestures is that they are used to impart additional information in a conversation. The scientists tested this by seeing whether blind speakers gesture to someone even if they know the listener is blind.
Nearly all the blind speakers gestured to a listener they knew was also blind.
"Thus blind speakers do not seem to gesture solely to convey information to the listener," say Ms Iverson and Ms Goldin-Meadow.
Another possible reason for gesturing, they conclude, is that gestures "may reflect, or even facilitate, the thinking that underlies speaking".Reuse content