While she was a young researcher working on a Ph.D. in psychology at the University of Pennsylvania, AAAS Fellow Susan Goldin-Meadow observed a young, deaf boy making unique gestures. Although he didn't know sign language, Goldin-Meadow realized that his gestures were not just random hand movements but were filled with meaning.
"It was immediately apparent that this child was using gesture to communicate with the hearing people around him," said Goldin-Meadow, professor of psychology at the University of Chicago, "but what was not clear was whether his gestures were structured like language."
These unschooled gestures, now known as homesigns, are a system of communication that profoundly deaf children develop when not exposed to conventional sign language by their hearing parents. Goldin-Meadow has devoted much of her career to studying homesigns, and believes they may yield important clues about how the mind works to create language in deaf and hearing people alike.
Although she was not the first scholar to notice the gestures, she was the first to study them seriously and to show that they resemble language in form and function. She also developed a coding system for researchers to use to characterize and study homesigns.
Goldin-Meadow found that homesigns are like other languages because deaf children use them to string their gestures together into sign "sentences" characterized by linguistic structure, even though they have no linguistic model from which to learn that structure. The homesigns are, for the most part, characterized by universal properties of language, such as nouns and verbs.
"Humans are prepared to communicate in a structured fashion," she observed.
To begin her research, Goldin-Meadow realized she would need to study the gestures of the hearing people around homesigning children. "To really understand the input that homesigners receive, I had to study the co-speech gestures hearing people produce," she said.
Although it looks qualitatively different from homesigning, co-speech gesture does in fact help people learn and communicate even though it doesn't look like language. Further, Goldin-Meadow observed that when novices—adults or children—convey one idea in gesture and a different idea in the speech or visual signs they use to accompany the gesture, the mismatch may signal to teachers they are ready to learn a new concept.
"This juxtaposition of two ideas, one in gesture and the other in sign, highlights their discrepancy, and this discrepancy might be what motivates the student to search for new information in the math lesson," said Goldin-Meadow.
Attentive teachers can seize on this "teachable" moment, she suggests.
Parents also can observe a child's gestures as a way of understanding new words the child is ready to learn and use that as a teaching moment. For instance, a child may use gesture to show they understand the meaning of a word before they can say it, signaling that they are ready to learn the word.
In another study, Goldin-Meadow and colleagues are exploring a different perspective on homesigning—properties of language that homesigners do not have, such as ways to indicate large, exact numbers with their hands. By looking at what is missing from homesigning——and how homesigners think about the concepts associated with these missing parts——she is hoping to build a more complete picture of how language and thought are related.
Goldin-Meadow and her students also have begun studying homesigners in Nicaragua. Three decades ago, homesigners there came together to create a new language——Nicaraguan Sign Language (NSL)——which has since been passed onto several generations of deaf individuals.
"Homesigns are the first stage of language emergence," she noted. "Now that Nicaraguan Sign Language is being passed down from one generation to the next, we have the opportunity to see the effects of new minds learning the system fresh. The work in Nicaragua can tell us how language begins and how it turns into a complex system."