Early exposure to signing helps deaf kids on mental task

WASHINGTON — Deaf children who learn to sign early may boost their brainpower in ways unrelated to language.

“Most deaf children are born to hearing families, and most hearing parents do not sign with their newborn deaf children,” clinical neuropsychologist Peter Hauser, who is deaf, explained February 12 at the annual meeting of the American Association for the Advancement of Science. “The deaf children, as a consequence, have very limited exposure to sign language,” signed Hauser, of Rochester Institute of Technology in New York.  

That paucity of input derails not only normal language development, but other aspects of mental performance, too, Hauser’s new research suggests. He and colleagues studied executive function — high-level mental effort that involves controlling attention, impulses and emotions — by having 115 deaf children draw lines between circles with sequential numbers. The kids had to alternate colors of circles, a tricky task because it required resisting the urge to connect circles of the same color. 

Compared with children exposed to signing from birth, children who didn’t learn to sign until around age 3 took about 17 seconds longer to connect the dots, Hauser reported. What’s more, the late signers don’t seem to ever catch up. In similar tests of 40 adults, native signers beat the times of late signers by 23 seconds.

This result “shows that it’s something that’s still there in adulthood,” says psychologist and language expert Jenny Singleton of Georgia Institute of Technology in Atlanta.

Earlier work by Singleton examined classrooms of deaf children, some exposed to signing from birth and some who learned to sign later. The late signers required more redirection to follow signed conversations, she and colleagues found. “We now have a preponderance of evidence to suggest that if they have not acquired language early, there can be lifelong impacts,” she says.

That means that families of deaf children who receive cochlear implants shouldn’t necessarily abandon attempts to sign, she says. If a child doesn’t succeed with the implant, then signing would still ensure that the child has a language to use.