Researchers associated with the Beckman Institute for Advanced Science and Technology at the University of Illinois at Urbana–Champaign have successfully used infrared eye tracking technology to collect data from hundreds of infants in an automated fashion.
Their findings, published in Neurotoxicology and Teratology, provide a new method of measuring looking behavior in infants, which is a reliable predictor of long-term cognitive outcomes.
“This study demonstrates that eye tracking technology can be used to automate assessments of infant looking behaviors that measure specific cognitive domains including information processing speed, attention, social cognition, and recognition memory,” the researchers wrote in their study.
The researchers were particularly interested in measuring side preference, fixation duration, and novelty preference among the infants. Novelty preference during infancy has been linked to several cognitive outcomes in later life, including verbal fluency, IQ scores and perceptual speed. Looking behavior in infants can also indicate prenatal exposure to heavy metals and drugs.
As part of the ongoing Illinois Kids Development Study, new mothers were invited to bring their infants to the research laboratory for cognitive assessment when the infants were approximately 7–8 months of age. The researchers used an EyeLink 1000 Plus infrared eye tracker to record the infant’s gaze during a visual recognition memory task that included both human faces and geometric figures as stimuli.
Previous versions of the task have relied upon research confederates to alter the stimuli and record gaze assessments.
“Traditionally, eye-tracking studies require you to keep your head still and avoid any movement so that the eye tracker can work properly,” said Andrea Aguiar, a research assistant professor of comparative biosciences at the University of Illinois at Urbana-Champaign. “This is not a feasible method when you study infants. Additionally, we needed an automated approach that was not subjected to individual examiners’ biases.”
In their new study, the researchers were able to automate the task using the eye tracking technology and computer-controlled stimulus presentation. More than 300 infants were assessed using this automated technique.
“We have the infants sit on their mom’s lap and ask the mom to look down at the baby’s head and remain neutral. We then display pictures of faces and shapes on a big screen and calibrate the eye tracker,” explained Francheska M. Merced-Nieves, a former graduate student in the Children’s Environmental Health Research Center. “The babies wear a target sticker in the middle of their forehead and the eye tracker measures the distance between the sticker and their cornea.”
In line with previous studies, the researchers found that most infants spent a longer time looking at novel stimuli compared to familiar stimuli. “We also confirmed the idea that most babies have a natural tendency to look toward their right side. Interestingly, when they were looking at the faces, they preferred looking at the eyes compared to the rest of the face,” said Susan Schantz, a professor emeritus of comparative biosciences and the director of the center.
The study, “Characterization of performance on an automated visual recognition memory task in 7.5-month-old infants“, was authored by Kelsey L.C. Dzwilewski, Francheska M. Merced-Nieves, Andrea Aguiar, Susan A. Korrick, and Susan L. Schantz.
