Eye-tracking reveals early social attention differences in preterm infants
Attention to other people is a cornerstone of early social-cognitive development. New research from Kyoto University shows that infants born prematurely display different patterns of social attention compared with full-term infants, with potential implications for later social communication and autism risk.
The study used eye-tracking to compare how 6- and 12-month-old preterm and full-term infants respond to social stimuli. The researchers found that many preterm infants showed less interest in people and had more difficulty following another person’s gaze. These early differences in attention to social cues may help explain why preterm children are reported to have a higher risk of social communication challenges, including autism spectrum disorder.
“Autism arises from a combination of genetic and environmental influences,” says Masako Myowa-Yamakoshi, leader of the research team. “The early environment for preterm infants is drastically different from the womb, and that stress can increase vulnerability to developmental difficulties even when infants appear healthy at hospital discharge.”
Lead author Masahiro Imafuku explains that reduced interest in social stimuli—such as a person’s face or movement—might be an early indicator that a preterm infant’s social development is following an atypical path. “We followed infants’ gaze with an eye tracker to measure their attention to social versus non-social visual input,” he says.
In the first experimental task, videos of people moving were presented alongside geometric motion patterns. The researchers measured which visual stimulus each infant preferred by recording gaze duration. Longer looking time at the people videos indicated greater interest in social information. Full-term infants generally spent more time watching the human movement, while a notable number of preterm infants—when tested at term-equivalent ages of 6 and 12 months—showed a stronger preference for geometric motion.
In a second task, the team assessed gaze-following: whether infants would look toward objects or locations that another person in the video was looking at. Gaze-following is an important early skill related to understanding others’ intentions and to later language development. Six-month-old full-term infants reliably followed the gaze cues, whereas many preterm infants had more difficulty doing so.
Importantly, the researchers observed that most preterm infants showed developmental gains in both interest in people and gaze-following between 6 and 12 months. Nevertheless, the pattern of early attentional differences suggests that the nervous system of some preterm infants develops along a different trajectory from that of full-term infants during the first year of life.
In a related investigation, the research team reported that the cries of preterm infants tend to be higher pitched and more shrill than those of full-term infants. The authors link this vocal characteristic to reduced activity of the vagus nerve—the main parasympathetic nerve—which plays a role in regulating heart rate, throat and vocal cord function, and broader physiological state.
“Lower vagal activity can cause excessive contraction of the vocal cords, producing the distinct shrill cry often observed in preterm babies,” says Yuta Shinya, author of the related study. “Because vagal activity is connected to physiological regulation and cognitive function, we are exploring whether these high-pitched cries correlate with later atypical cognitive development.”
Incidence of preterm birth is rising in many developed countries, including Japan, a trend partly associated with increasing maternal age and greater use of assisted reproductive technologies. “We hope this research contributes to earlier identification of developmental risk and to timely support for families,” Myowa-Yamakoshi says.
Funding: The study was supported by the Japan Society for the Promotion of Science, the Ministry of Education, Culture, Sports, Science and Technology, and the Japan Science and Technology Agency.
Source: Anna Ikarashi – Kyoto University
Image Source: Image credited to Anna Ikarashi.
Original Research: Abstract for “Preference for Dynamic Human Images and Gaze-Following Abilities in Preterm Infants at 6 and 12 Months of Age: An Eye-Tracking Study” by Masahiro Imafuku, Masahiko Kawai, Fusako Niwa, Yuta Shinya, Michiyo Inagawa and Masako Myowa-Yamakoshi in Infancy. Published online March 31, 2016. DOI: 10.1111/infa.12144
Abstract
Preference for Dynamic Human Images and Gaze-Following Abilities in Preterm Infants at 6 and 12 Months of Age: An Eye-Tracking Study
Preterm children are reported to have a higher risk of social communication problems, including autism spectrum disorder, compared with full-term children. While early preference for social stimuli has been proposed as a predictor of later social communication development, little is known about this relationship in preterm infants. This study compared gaze behavior in low-risk preterm and full-term infants at 6 and 12 months corrected age using two eye-tracking tasks: 1) measurement of preference for social stimuli (dynamic human biological motion versus geometric motion) and 2) assessment of gaze-following ability.
Results showed that, at both 6 and 12 months, preterm infants spent less time looking at dynamic human images, followed another person’s gaze less often, and spent less time observing objects cued by another’s gaze compared with full-term infants. At 12 months, looking time for dynamic human images correlated with frequency of gaze following in full-term infants but not in preterm infants. The authors discuss how atypical gaze behavior patterns in preterm infants may relate to their elevated risk for later social communication difficulties.