Study Finds That by 15 Months Infants Can Learn New Words for Unseen Objects through Language Alone

A groundbreaking study by researchers at Northwestern University and Harvard University has revealed that infants as young as 15 months can begin to learn new words for objects they have never seen, highlighting the remarkable capabilities of early language acquisition. This research sheds new light on how infants develop mental representations of objects based solely on linguistic input. 

The study involved 134 infants, split into two groups of 67 at ages 12 and 15 months. The researchers employed a three-part task to evaluate word learning. Initially, infants were shown familiar objects paired with their names (e.g., apple, banana). Subsequently, they heard a new word while the image of an unfamiliar object (such as a kumquat) was hidden from view. Finally, when two novel objects (the kumquat and a whisk) were presented, the researchers asked the infants to identify the kumquat. 

The results were striking: 15-month-old infants looked significantly longer at the novel fruit (kumquat) compared to the novel artifact (whisk), indicating that they could use contextual clues from the conversation to infer the meaning of the new word. In contrast, the 12-month-olds did not exhibit the same recognition, suggesting that this ability develops between 12 and 15 months. 

Senior author Sandra Waxman, a professor of psychology and director of the Infant and Child Development Centre at Northwestern, explained, “The study shows that even babies who are just beginning to say their first words learn from the language they hear, even if the objects or events being discussed are not present.” This finding suggests that infants can form initial mental representations or “gists” of new words, which they can later use when encountering the actual object. 

Waxman further noted that at 12 months, infants may not yet possess enough understanding of familiar words to begin forming meaningful associations with new words. However, by 15 months, they demonstrate a capacity to learn from conversational contexts, a critical skill for language development. 

This study emphasises the importance of early language exposure in infants’ lives. As they listen to conversations and read books, infants often hear words they do not yet understand—words that cannot be directly linked to an object. The findings indicate that they can still build a foundational understanding of these terms through the context in which they appear. 

As language development plays a pivotal role in cognitive growth, these insights highlight the need for caregivers and educators to engage infants in rich linguistic environments, fostering their innate ability to learn and understand new words. 

For further details, you can read the full study on Northwestern Now: By 15 months, infants begin to learn new words for objects — even if they’ve never seen them.