Baby, Read My Lips. Finding About Language Development Could Impact Autism Diagnoses
The development of communication skills begins in infancy, even before a baby utters his or her first word. During the first few months of life, infants appear to get much of their knowledge about words and sounds by listening to those around them. But a new study finds that babies are pretty good lip readers as well.
David J. Lewkowicz, a professor of psychology at Florida Atlantic University, and Amy Hansen-Tift, a doctoral student, tested nearly 180 babies in groups at ages 4, 6 8, 10 and 12 months of age. The children watched videos of women speaking either in English, the native language used at home, or in Spanish, a language that was foreign to the families. The researchers used an eye tracker device to study eye movements.
At four months of age, the babies focused almost solely on the women’s eyes while watching the English-language videos. But by six to eight months, when the infants reached the “babbling” stage of language acquisition when they make more speech-like sounds, they shifted their focus to the women’s mouths, likely in an effort to imitate the women’s lip shapes in order to create particular sounds.
They continued to focus on this portion of the face until about 10 months of age, a point researchers noted they shifted their attention back to the eyes, likely due to the emergence of true speech and the ability to cognitively understand social cues and non-verbal messages.
As adults, we tend to focus on a person’s eyes when they are speaking, unless we have trouble understanding, then we shift our focus to the mouth. In a second experiment, the babies viewed videos of women speaking Spanish, which was not the infants’ native language. The babies’ attention shifted to “lip-reading” later – at about 8 months of age instead of six. They continued to focus on the mouths of the women in the video until about 12 months.
During well-visit check-ups, pediatricians will use a chart of developmental milestones to assess whether or not a child is developing normally. The researchers suggest that the English-speaking babies, when listening to an unfamiliar language, react similarly to infants who are not developing language skills at the typical rate. Children who continue to focus on the mouth past 12 months are “probably not developing age-appropriate perceptual and cognitive skills and may be at risk for disorders like autism,” Lewkowicz says.
Although more research is needed, the findings of this study could perhaps diagnose autism spectrum disorders (ASD) earlier in an infant’s life, thus providing them with as much as six more months of early intervention. “The earlier we can diagnose it (autism), the more effectively we can ensure the best possible developmental outcomes,” says Lewkowicz.
Proceedings of the National Academy of Sciences
American Speech-Language-Hearing Association, “Typical Speech and Language Development”, accessed January 17, 2012.