The brain spreads its sights in the deaf
By Bruce Bower
People often assume that the deaf, because they live in a silent world, compensate by seeing more vividly or clearly than the hearing do. Yet scientists know little about the visual capacities of deaf people.
A new study finds that compared with hearing adults, people who have been deaf from birth display a unique pattern of activity in the brain’s visual system that may strengthen their peripheral vision.
A brain area implicated in tracking objects that move on the fringes of a person’s visual field exhibits elevated activity in deaf individuals, says a team of neuroscientists led by Daphne Bavelier of the University of Rochester. This brain response arises from deaf people’s unusually high reliance on peripheral vision, the researchers propose. For instance, they note, deaf people regularly scan their surroundings to compensate for the absence of acoustic cues and typically monitor the arm and hand motions of sign language with peripheral vision while looking at a conversation partner’s eyes.