For parents of young children, there are few milestones more memorable than that first word. But people communicate an awful lot to each other without ever saying anything at all. That raises an intriguing question: how do infants learn to communicate with the people around them nonverbally, through eye contact? Researchers reporting in the Cell Press journal Current Biology on November 19 have some new insight into this silent form of communication from an unlikely source: the sighted children of blind parents.
“Infants of blind parents allocated less attention to adults’ eye gaze,” says Atsushi Senju of Birkbeck, University of London. “It suggests that infants are actively learning from communicating with their parents and adjusting how best to interact with them.”
Senju says it’s important to note that those infants developed typical overall social communication abilities, suggesting that the patterns of difference the researchers observed were limited specifically to the babies’ attention to adults’ eye gaze.
Eye gaze is an important channel for communication, and human infants show an amazing ability to recognize and react to adults’ gaze. Senju and his colleagues wondered how infants develop their attention to the eyes when their primary caregiver can’t make eye contact or react to infants’ gaze because they can’t see.
To find out, the researchers used eye-tracking technology to assess face scanning and gaze following in 14 sighted infants of blind parents at 6 to 10 months and then again at 12 to 16 months of age. They also watched as the infants interacted with their blind parent and with an unfamiliar sighted adult.
In comparison to a group of infants with sighted parents, infants whose parents were blind paid less attention to adults’ eyes, the researchers report. The children with blind parents were otherwise typical in their development. In fact, in some ways, they even excelled.
“Infants of blind parents showed advanced visual attention and memory skills when they are 8 months old, which we did not expect when we started this project,” Senju says.
He says it’s possible that the need to switch communication modes between blind parents and other sighted adults might boost infants’ early development of visual attention and memory.
Senju says they don’t yet know how long lasting the differences in the infants born to blind parents will be. It’s possible they might diminish as children interact more with peers and other sighted adults. They are now following up these children at the age of three to study their longer-term development. In the near future, they also want to explore development in another interesting group of babies–the hearing infants of deaf parents.
Funding: This work was supported by a UK Medical Research Council Career Development Award, a UK Economic and Social Research Council Research Fellowship, the BASIS funding consortium led by Autistica (http://www.basisnetwork.org), and a UK Medical Research Council Programme Grant.
Source: Joseph Caputo – Cell Press
Image Credit: The image is credited to The Babylab, Birkbeck, University of London
Original Research: Full open access research for “Early social experience affects the development of eye gaze processing” by Atsushi Senju, Angélina Vernetti, Natasa Ganea, Kristelle Hudry, Leslie Tucker, Tony Charman, and Mark H. Johnson in Current Biology. Published online November 19 2015 doi:10.1016/j.cub.2015.10.019
Early social experience affects the development of eye gaze processing
•Infants of blind parents allocate less attention to adults’ eyes and gaze direction
•Differences in gaze processing in these infants become greater after 12 months of age
•Overall social communication skills development of them were within the typical range
Eye gaze is a key channel of non-verbal communication in humans [ 1–3 ]. Eye contact with others is present from birth [ 4 ], and eye gaze processing is crucial for social learning and adult-infant communication [ 5–7 ]. However, little is known about the effect of selectively different experience of eye contact and gaze communication on early social and communicative development. To directly address this question, we assessed 14 sighted infants of blind parents (SIBPs) longitudinally at 6–10 and 12–16 months. Face scanning [ 8 ] and gaze following [ 7, 9 ] were assessed using eye tracking. In addition, naturalistic observations were made when the infants were interacting with their blind parent and with an unfamiliar sighted adult. Established measures of emergent autistic-like behaviors [ 10 ] and standardized tests of cognitive, motor, and linguistic development [ 11 ] were also collected. These data were then compared with those obtained from a group of infants of sighted parents. Despite showing typical social skills development overall, infants of blind parents allocated less attention to adult eye movements and gaze direction, an effect that increased between 6–10 and 12–16 months of age. The results suggest that infants adjust their use of adults’ eye gaze depending on gaze communication experience from early in life. The results highlight that human functional brain development shows selective experience-dependent plasticity adaptive to the individual’s specific social environment.
“Early social experience affects the development of eye gaze processing” by Atsushi Senju, Angélina Vernetti, Natasa Ganea, Kristelle Hudry, Leslie Tucker, Tony Charman, and Mark H. Johnson in Current Biology. Published online November 19 2015 doi:10.1016/j.cub.2015.10.019