Blinks, Winks and Nods Reveal Infants Do Learn at an Early Age By Emil Venere Scientist Marie Balaban is using sophisticated laboratory techniques that measure how babies respond to everyday stimuli like facial expressions and changes in a musical melody. One fact is apparent: infants develop cognitive skills at an astonishingly young age. Dr. Balaban, an assistant professor in the Psychology Department, specializes in early perceptual and cognitive development. In addition to observing infant behavior, she studies the subtle, yet telling physiological reactions that reveal how infants perceive and understand their environment. The developmental psychologist uses "unobtrusive" methods to probe the workings of the infant mind. "In other words, measures that can be obtained while you're sitting here talking to me," she said. For example, the babies are outfitted with headphones for research on how they perceive changes in melody. In another study, their blink reflex is monitored with sensors attached to their cheeks as they are shown photographs of angry, neutral and happy faces. "We can't ask the infant, do they know that an angry face is negative," said Dr. Balaban, who arrived at Hopkins in August after working five years at Harvard University. She has spent much of the summer and fall setting up her laboratory. In addition to the usual scientific gear, her lab has a few uncustomary features: a waiting room equipped with suitable toys and a table for changing diapers, another room with a one-way mirror that enables researchers to make inconspicuous observations. While babies cannot communicate verbally, their physiological reactions are often similar to those of adults. By studying those reactions, scientists can draw inferences about the things infants perceive. Research reveals that something happens early in the development of infant brains that enables babies to understand the difference between anger and joy. Dr. Balaban and researchers in her laboratory show the babies a series of faces depicting anger, joy or neutrality. The infants are monitored for their "startle reflex," which is triggered by producing a brief, unexpected sound while the babies are looking at pictures. Then the scientists record the eye-blink response to the sound. The strategy is to draw parallels between how adults and infants respond physiologically when looking at an angry face, compared with a happy face. "Even if you hardly move at all, you will blink," said Dr. Bala-ban, who recently received a two-year grant from the National Institute of Mental Health to further her research. "If you are looking at a picture that is negative in terms of its affective component, then your reflex response to, say, an unexpected sound is heightened during that negative theme," she said. "Whereas, if you are looking at a positive picture your reflex response to that same kind of sound is reduced. "Our evidence seems to show that by five months they are showing some kind of physiological discrimination," Dr. Balaban said. She also is studying how the infant brain recognizes changes in melody. Scientists know that, in certain types of perceptual tasks, the right side of the brain is best at recognizing an overall outline, such as the relation of the features on a face, or the general structure of a melody. The left side specializes more in analysis, or picking out smaller pieces of the puzzle. One of her recent studies strives to determine how an infant perceives change in melody, specifically, whether the brain's left hemisphere is better at detecting minute changes in notes and intervals and whether the right hemisphere is best at perceiving alterations to the overall melody. "We know that they can detect changes in melody fairly early, probably around five months," Dr. Balaban said. She studies older infants--between eight and nine months--to determine how they distinguish change in melody. The right ear sends more information to the brain's left hemisphere, and the left ear sends more information to the right hemisphere. By placing headphones on the infants, Dr. Balaban said, researchers can study the brain's perception of melody change. "We vary it so that sometimes the melody changes only in the left ear, and sometimes it's only in the right ear," she said. Preliminary findings show that infants use the right hemisphere more for perceiving the overall contour of the melody. Between 24 to 36 babies will enroll in the studies, said Dr. Balaban, who located the infants by looking up birth records in newspapers and sending query letters to the parents. She also took out ads in publications specializing in baby care. Parents are a vital component in the research. They generally are not paid but sometimes receive a small travel reimbursement or stipend. "One of the reasons we know as much as we do is because parents bring their babies in," Dr. Balaban said. Heather Jackson is one of those parents. Shortly after receiving a letter from the Hopkins researcher, Jackson brought her son Joshua to the lab, where he was enrolled in the melody study. "He's my baby and I watch him, but I really don't sit there and study how he learns," said the Hanover woman, a secretary in the engineering and fabrication branch at the Applied Physics Laboratory. "Even though they explained it to me over the phone, it was very different than what I had imagined," she said. "I thought it was very interesting."
Go to Gazette Homepage