EVANSTON, Ill. --- A new Northwestern University study shows the power of language in infants' ability to understand the intentions of others.

As the babies watched intently, an experimenter produced an unusual behavior--she used her forehead to turn on a light. But how did babies interpret this behavior? Did they see it as an intentional act, as something worthy of imitating? Or did they see it as a fluke? To answer this question, the experimenter gave 14-month-old infants an opportunity to play with the light themselves.

The results, based on two experiments, show that introducing a novel word for the impending novel event had a powerful effect on the infants' tendency to imitate the behavior. Infants were more likely to imitate behavior, however unconventional, if it had been named, than if it remained unnamed, the study shows.

When the experimenter announced her unusual behavior ("I'm going to blick the light"), infants imitated her. But when she did not provide a name, they did not follow suit.

This revealed that infants as young as 14 months of age coordinate their insights about human behavior and their intuitions about human language in the service of discovering which behaviors, observed in others, are ones to imitate.

"This work shows, for the first time, that even for infants who have only just begun to 'crack the language code,' language promotes culturally-shared knowledge and actions - naturally, generatively and apparently effortlessly," said Sandra R. Waxman, co-author of the study and the Louis W. Menk Professor of Psychology at Northwestern.

"This is the first demonstration of how infants' keen observational skills, when augmented by human language, heighten their acuity for 'reading' the underlying intentions of their 'tutors' (adults) and foster infants' imitation of adults' actions."

Waxman said absent language and its power in conveying meaning, infants don't imitate these "strange" actions.

"This means that human language provides infants with a powerful key: it unlocks for them a broader world of social intentions," Waxman said. "We know that language, and especially the shared meaning within a linguistic community, is one of the most powerful conduits of the cultural knowledge that we humans transmit across generations."

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The study "Shall We Blick?": Novel Words Highlight Actors' Underlying Intentions for 14-Month-Old Infants" was published in Developmental Psychology in July. Marian L. Chen, a post-doctoral researcher in the Child Cognition Lab at Boston University, is also co-author of the study.

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