Parents always think their babies are the cutest and the brightest, but new findings from Penn researchers suggest that moms and dads may, in fact, be underestimating their young children in one crucial way: their ability to understand language.

In a study published in the Proceedings of the National Academy of Sciences, doctoral student Elika Bergelson and associate professor Daniel Swingley, both of the Department of Psychology in the School of Arts and Sciences, found that babies can understand the meaning of many common nouns, such as “yogurt,” “hair,” or “bottle,” as early as 6 months of age. That is significantly younger than most researchers previously believed, and many months before most children speak their first word.

Swingley and Bergelson uncovered this hidden knowledge by displaying images of food items and body parts on a screen to a child sitting on his or her caregiver’s lap. Through headphones, the caregiver was prompted to say a phrase identifying one of the objects being displayed. Examples include “Where’s the nose?” or “Look at the banana.” Using a specialized eye-tracking device, the researchers then noted whether the child looked at the named object longer than unnamed objects.

On average, the 33 babies tested—6 to 9 months old—gazed longer at the named objects, indicating to the researchers that they understood the meaning of the spoken words.

Swingley, also director of Penn’s Infant Language Center, where the research was conducted, says these findings are a welcome message for parents.

“When you do talk to [your baby], you are building a social relationship and you are in a way teaching him or her that language is a tool for communication about things in the world,” he says.

The next step for Bergelson and Swingley is to test words that are more abstract, such as “uh-oh” and “all gone,” to see if infants grasp the meaning of words and phrases that are not concrete nouns.

Abstract nouns might be more difficult to learn, Bergelson says, because “the situations in which you would say ‘uh-oh’ are going to vary a lot.”

Ongoing studies in the Infant Language Center examine different aspects of infant word learning and word recognition, and researchers are seeking children between the ages of 6 months to 3 years to participate.

For more information, visit the Infant Language Center website.