Study: Names change how an infant’s memory encodes objects

The human mind brims with fascinating mental tools. One such tool is our ability to perceive and categorize the world for both groups and individuals. Because we are so accustomed to our minds, that may not seem remarkable but it’s quite something. Even more remarkable, we develop this capacity at an incredibly young age.

Children understand, for example, that bunnies have long ears, fast feet, cotton-ball tails, and fluffy coats. But a child also understands that Sir Flops is both a bunny but an individual. He has a star-shaped patch on his rump, likes broccoli more than carrots, and enjoys a good scratch behind the ears. Children manage this distinction before they have acquired an encyclopedia’s worth of names and details to check and cross-reference to ensure proper mental categorization. But how?

Drs. Alexander LaTourrette and Sandra Waxman, psychologists at Northwestern University, have proposed that language, specifically naming conventions, determine how infants encode objects into memory—whether as part of a group or as an individual. Their new study, published in the Proceedings of the National Academy of Sciences, suggests they are on to something.

An image showing the stuffed animals introduced during the training phase followed by the new ones introduced in the test phase. (Photo: Alexander LaTourrette and Sandra Waxman/PNAS)

To test their hypothesis, LaTourrette and Waxman did what all good scientists do: set up an experiment. They enlisted the help of 77 infants, each between eleven-and-a-half and twelve-and-a-half months old, and trained them to recognize stuffed animals. They showed the infants a parade of stuffed animals and introduced them with a novel name.

During this training phase, the infants were divided into three groups. The first group, the consistent name group, was introduced to the stuffed animals with a single signifier. For example, even though the stuffed animals were a piglet, kitten, duckling, and panda, each one would be referred to as a “boff.”

The second group, the distinct name group, was also presented with the four stuffed animals. But this time, each one was given a unique signifier. The kitten would be called a “boff,” but the duckling an “etch,” the piglet an “arg,” and the panda a “dov.”

The third group was enlisted as the control. For this group, each stuffy introduction was paired with a monotone voice. This is because tone, unlike names, has been shown to not facilitate categorization.

The researchers’ goal was to determine how each naming convention encoded the stuffed animals within the infants’ memories over several training trials. When the stuffies were introduced as a “boff,” then the infants’ memories should encode them as a unified category. Like in our bunny example above, they would perceive the commonalities of “boffness”—big round eyes, soft fury, and cuddly tummies.

Conversely, when the stuffies were introduced by distinct labels, then the infants’ memories should encode for individuation. As with Sir Flops, they would perceive distinguishing features and tag those in their memory for later recall—etch has yellow fur and wings while arg sports pink fur and a snout.

Getting Inside the Mind of an Infantwww.youtube.com

Of course, LaTourrette and Waxman couldn’t ask the infants how they remembered their colorful compatriots. So, they utilized a recognition memory test to find out. The researchers reintroduced the infants to the stuffed animals from the previous training alongside a never-before-seen fuzzy friend. The researchers then recorded the children’s gazes.

They theorized that if infants stared equally at both “boffs,” then they recognized the commonalities between them and had encoded for a category. However, if the infants stared longer at the new toy, that indicated that the infant recognized the original object and was spending time memorizing the new, individualized, object.

That’s exactly what they found. Infants from the consistent name group stared at both stuffed animals for equal time, suggesting they recognized the commonalities at the expense of distinctive features. The distinct name group recognized the individuals more readily and turned their attention to the new stuffy. The control group only recognized the more recent stuffed animal.

“Our findings reveal a powerful and sophisticated effect of language on cognition in infancy: the way in which an object is named, as either a unique individual or a member of a category, influences how [twelve-month-old] infants encode and remember that object,” the researchers write. “Hearing a consistent name applied to a set of objects focuses infants on the commonalities among them, while hearing distinct names applied to the same objects focuses infants on the uniqueness of each object.”

The researchers expressed hope that their research would help cognitive psychologists gain a deeper understanding of how names influence people, from infancy to adulthood, in their conceptual representations. They also hope that this evidence opens further investigations, such as how familiar nouns (rather than novel names) influence infant representations.

They conclude, “Even a single naming episode can have a lasting impact, influencing how infants encode that object, represent it in memory, and remember it later.”