RESEARCH

Busy Baby Brains

Chances are, your 6-month-old baby isn’t yet standing up, saying words or crawling around the house. He or she may just recently have learned to sit without support or eat solid food.    

Contrary to what you see, however, there appears to be a surprising amount of sophisticated activity inside the brain of this drooling, babbling infant.    

New research published in the journal Psychological Science by lead author Paul Quinn, professor of psychology at UD, indicates that babies as young as 6 months are able to recognize similarities among objects. Not only that, Quinn says, but they apparently mentally organize the objects into categories, laying an important early foundation for future learning. 

“What we think we’re seeing is the beginning of concept formation in the brains of these 6-month-olds,” Quinn says. “We believe that babies are not seeing the world as an undifferentiated cluster of items but that they’re forming categories for what they see.

“Just as we adults use file folders to organize our professional lives, that’s also how we organize the knowledge we have in our heads, and then we add information to each category as we learn more about it. Now, we think that babies are starting to do that at a very young age—long before they have any formal education or even the ability to speak.”

For some time, he and other researchers have observed babies’ eye fixations, measuring how long they spend looking at various objects or images, to assess how the infants react to what they see. The resulting data have suggested that even very young children appear to be mentally sorting things into categories. The newly published study has taken the earlier work a step further, measuring brain-wave activity that supports the looking-time observations.

Quinn conducted the brain-wave research during a 2004 research leave at a high-tech lab investigating various aspects of infants’ brain development. The lab, which at the time was at the University of Minnesota, now has moved to Harvard University with its director, Charles A. Nelson. Nelson and Alissa Westerlund, also of Harvard, are co-authors of the Psychological Science article.

In the study, researchers placed a cap known as a “neural net,” made up of 64 tiny sponge electrodes that rest on the scalp, on babies’ heads as they sat on a parent’s lap. The sensors measured and recorded the electrical activity in various areas of the brain, which the researchers then compared with what the infant was seeing at a specific time.

Quinn first showed the babies photos of cats and found that, even though each image depicted a different cat, the infants began to show less interest in the later photos, indicating that they recognized them as a familiar—and therefore boring—category. This loss of interest continued as the researchers moved on to showing the babies another group of cat photos. Again, even though the infants hadn’t seen these specific animals before, they seemed to recognize that they were a familiar category.

But, when shown photos of dogs interspersed with the second group of cats, the babies’ interest clearly revived as they looked at the new type of animal, Quinn says. The brain-wave activity showed the same renewed interest that the earlier looking-time studies had indicated, he says.

“Just like us, babies like to look more at things that are new to them,” Quinn says, adding that an exception is people’s faces, in which infants prefer their parents to strangers. “In the same way that we do, they get bored with things they’ve seen repeatedly, and you can see this in the way a brain signal rises and falls. What we found is that, not only did these infants recognize the similarities among the cats, but they also recognized that the cats were different from dogs.”

Quinn’s lab at UD, coordinated by Laurie Yarzab and operated with the help of undergraduate research assistants, is continuing to conduct studies of infant eye fixations. A separate Department of Psychology research lab, operated by Prof. James Hoffman, uses neural nets to measure brain-wave activity in adults.

By combining some resources from the two labs, Quinn says, he hopes to continue his infant brain-wave research at UD. Future studies might expand the categorization research by showing babies images of objects that are not animals or by delving into how infants respond to faces showing a variety of emotions, he says.

In a letter seeking research participants, Quinn tells parents: “If your baby helps us to understand what the average baby can do, some day we might be able to develop tests to identify those infants who are at risk for developing perceptual and memory problems.”

Having such young research participants poses special challenges, Yarzab says, including squirming, fussing and becoming distracted away from looking at the designated objects or pictures. Still, about 85-90 percent of the babies whose parents volunteer their services do complete enough of any given looking-time study to generate usable data, she says.

In the lab at the University, Yarzab has plenty of toys and other distractions available to help calm a baby who might be feeling unsettled at the start of a session. She locates volunteers for the research by contacting parents of newborns, and she says many are eager to help advance the cause of science and, perhaps at the same time, better understand how their own babies are developing.

When a baby is ready to be observed in the lab, he or she sits on a parent’s lap and is shown photos, one at a time, of cats or other animals or objects. A video monitor records the amount of time the infant spends looking at each picture. At the same time, an observer watches the baby’s eyes through a peephole, also monitoring how long the infant stares at each picture before losing interest.

Quinn says he relies on help from undergraduate research assistants who log regular hours in the lab. In addition to their practical work learning how to conduct psychological research, the students also complete reading assignments and take tests, in exchange for academic credit.

“The students get hands-on experience, which they find very interesting and also fun,” Quinn says. “Some have done posters and other presentations about the research, and some have returned to the lab after the semester was over to pursue additional research, including original ideas for studies. We’ve had some very talented undergraduates.”

Quinn, who earned his doctorate at Brown University, joined the UD faculty in 2003 from his previous position at Washington & Jefferson College. He is a fellow of the American Psychological Association and serves as associate editor for both Child Development and Developmental Science, as well as on the editorial boards of several other psychological journals. His current research is funded by the National Institute of Child Health and Human Development.

Ann Manser AS ’73