Baby see, baby do.
New research has found that babies learn to speak by reading their parents’ lips, not by listening to spoken words.
A new study in the Proceedings of the National Academy of Sciences reports babies use their eyes more than their ears when acquiring language – a finding that could lead to earlier diagnosis and treatment for autism disorders that affect one in 110 children in the United States.
In the study, Florida Atlantic University researchers tested infants -- ranging from four to 12 months of age -- and a group of adults for comparison. The babies watched videos of women speaking in English or Spanish. Eye-tracking equipment monitored the babies’ eye movements, and researchers watched for changes in attention to the eyes and mouth.
At four months of age, the study found babies focused mostly on the women’s eyes. But by eight months of age, when the infants begin “babbling,” they tended to focus on the women’s lip movements. The babies continue to “lip read” until about 10 months of age, when they finally begin mastering the basic features of speech.
David Lewkowicz, an expert on infant perceptual development and lead author of the study, said that by 12 months “babies are already producing their first words and have mastered the first sounds and structures of the language." said.
As part of the study, videos of a Spanish-speaking woman were shown to English-learning babies between 4 and 12 months of age. “These babies were experts at English, and now when they heard Spanish, it was like 'Ok, this is weird, I better start looking at the mouth again, instead of the eyes, so I can figure out what's going on,” researchers said.
“These babies were experts at English, and now when they heard Spanish, it was like ‘Ok, this is weird, I better start looking at the mouth again, instead of the eyes, so I can figure out what’s going on.'”
Lewkowicz added that the research suggests that babies who continue to focus on lip reading and mouths past 12 months of age, may be at risk for developmental disorders, such as autism.