Action & Brain Lab research shows how early exposure to sign language enhances perception

Imagine you are watching a ballet performance with a friend who is a professional ballerina, suggests Dr. Lorna Quandt, Co-Director of Gallaudet's Visual Language and Visual Learning Center. Assuming you are not also a professional ballerina, the two of you are experiencing something different. "She knows the names of the moves, and she has done the moves. You're just watching something interesting to look at," she says. Because of that, your friend will be more accurate at predicting how the choreography will unfold.

Using this idea, Quandt's Action & Brain Lab (ABL) has been digging into a related question: Are people who are fluent in sign language experts in human movement more generally? ABL's new paper on this research, "Differences in Biological Motion Perception Associated with Hearing Status and Signed Language Exposure," has been officially accepted for publication in the Journal of Experimental Psychology: General.

To test her question, Quandt had subjects look at moving images on a screen. Each participant saw a display of moving dots representing the joints on the body of a person engaged in a physical activity. "Instead of seeing a person running or swinging a golf club, you just see the dots, which is this pared down, simplistic representation," she explains. Then they were asked whether this movement requires a ball. To make the test more difficult, some of the videos were flipped upside down.

Quandt and her team found a concrete difference in the results. "Deaf people responded much faster than hearing people," she says. "The earlier you are exposed to ASL, the more accurate you are with this test."

These findings are important to the field of cognition and perception, says Quandt, who is excited to show how experiences can transfer across domains. "Signers are showing benefits in movement outside of their area of expertise. They are better at perceiving sign language, but that's not surprising. They are also better at something they haven't been practicing," she says.

Quandt notes another reason these findings matter. "It adds to the growing literature of what people call deaf gain - what can you do better than people who are hearing or don't know sign language," she says. "If you knew that learning sign language could help your perception skills, it could tilt you toward learning it."

It is also relevant to an ongoing debate over whether deaf people should be allowed to drive. "If we have literal data showing that deaf people see movement better, maybe that can fight against backward-thinking laws," Quandt says.

As the next step in her research, Quandt plans to look into the neural underpinnings of this heightened perception and try to understand more about what is happening in a deaf person's brain while seeing movement​.

This figure shows some of the moving images that subjects looked at for this research into ASL and perception. Above, Dr. Lorna Quandt (in a white sweater) gives an overview of the Action & Brain Lab's work at a recent open house.