Summary: Infants as young as 15 months can use language context to infer the meaning of words referring to objects they’ve never seen. Researchers found that when 15-month-olds heard a new word in a familiar context—like “kumquat” during a conversation about fruit—they later identified the unseen object correctly.
This ability to form a mental “gist” of meaning without direct visual cues marks an early milestone in abstract learning and language development. The findings highlight that babies are not just passive listeners—they actively construct knowledge from the language they hear, even about things they can’t see.
Key Facts:
- Early Word Inference: 15-month-old infants can infer meanings of unseen words using context.
- Mental Representation: Infants form a “gist” of new words, even without visual cues.
- Developmental Insight: The study reveals how language fuels abstract learning in infancy.
Source: Northwestern University
Human language allows us to learn new words for things we’ve never witnessed directly. We do this seamlessly, for example, in conversations, using clues from the overall context to infer a new word’s meaning.
But how early does this ability become available? And what makes it possible to create a new mental representation of an object or event that we cannot see directly?
A new study by developmental scientists at Northwestern University and Harvard University offers the first evidence that infants as young as 15 months can identify an object they have learned about from listening to language — even if the object remains hidden.
Imagine an infant playing with blocks on the floor while listening to parents talk about kumquats in a conversation about more familiar fruits like apples and bananas.
Might the infant form an initial representation, or gist, about what kumquat means — something edible, likely a fruit? Can they then use this initial gist later when the infant first sees a novel fruit?
These are the questions the researchers sought to answer.
“Many people believe that success in word learning requires that the infant ‘map’ a new word to an object that is physically present (e.g., “Look at the kumquat!”).
“But in the natural course of a day, it is very common for us — and for infants — to hear words when the objects to which they refer to are not available to our immediate perception,” said senior author Sandra Waxman.
“We’re asking whether infants, too, can use the conversational contexts in which a word occurs to begin to learn their meaning.”
Waxman is the Louis W. Menk Professor of Psychology, director of the Infant and Child Development Center and an Institute for Policy Research Fellow at Northwestern.
The study’s co-author is Elena Luchkina, formerly a postdoctoral fellow at Northwestern, and now a research scientist at Harvard.
The researchers engaged 134 infants, 67 each at 12 months and 15 months in a three-part task.
First, the researchers presented infants with words they understand, paired with an image of the object to which it referred (e.g., apple, banana, grapes). Next, infants heard a new word while the image of a novel object (e.g., a kumquat) was hidden from their view.
Finally, two novel objects appeared (e.g., a kumquat and a whisk) and infants were asked, e.g., “where is the kumquat?”
Fifteen-month-olds, but not 12-month-olds, looked longer at the novel fruit (e.g. kumquat) than the novel artifact (e.g., whisk).
Although they had never seen any object paired with that novel word, 15-month-olds nevertheless used the context clues to identify which object was most likely the one to which the novel word referred.
“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,” Waxman said.
“Babies take in what they hear, and even if no object is present, they form a mental representation, or ‘gist’ of the new word’s meaning, one that is strong enough for them to use later when its referent object does appear.”
Waxman suggested that at 12 months, infants may not yet know enough of the familiar words they heard in the context to begin to form a representation or gist of the new word’s meaning (e.g., that it is likely another fruit).
Gleaning the meaning of kumquat
By introducing infants to novel words in the absence of any visible object, the researchers devised a powerful test of how much infants can learn about the meaning of a novel word based on language input alone.
The study provides new insight for the developmental origins of the human capacity to learn about things that are not perceptually present. It also begins to address how, and how early, the human mind can create mental representations of objects and events never witnessed directly.
This new work also highlights the power of language in infants’ daily lives. In listening to conversations and in book-reading, infants often hear words that they don’t yet understand, and that they cannot ‘map’ immediately to an object or event.
The results of this study show that by 15 months, infants spontaneously use the linguistic context in which a new word occurs to build a gist of its meaning that will support subsequent learning.
“When we hear new words, like “kumquat” in conversation when there are no kumquats around, we don’t waste the opportunity to home in its meaning,” Waxman said. “We now know this is also true about tiny babies.”
About this language and learning research news
Author: Stephanie Kulke
Source: Northwestern University
Contact: Stephanie Kulke – Northwestern University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“By 15 months, infants begin to learn new words for objects, even those they’ve never seen” by Sandra Waxman et al. PLOS One
Abstract
By 15 months, infants begin to learn new words for objects, even those they’ve never seen
Human language permits us to call to mind representations of objects, events, and ideas that we cannot witness directly, enabling us to learn about the world far beyond our immediate surroundings. When and how does this capacity emerge?
To address this question, we evaluated infants at 12 and 15 months, asking whether they establish a representation of a novel noun’s meaning in the absence of any visible referents, and use this representation to identify a candidate referent when it later becomes available.
During training, infants (67 12-month-olds; 67 15-month-olds) were primed with words and images of objects from a particular semantic neighborhood (e.g., fruits) and were also introduced to a novel noun (e.g., “a modi”), used to name a hidden object.
During test, infants heard that noun again, this time with two unfamiliar objects present—one from the primed neighborhood (e.g., a dragon fruit) and the other from an unrelated semantic neighborhood (e.g., an ottoman).
If infants can represent something about the meaning of the novel noun in the absence of a visible referent and then use such a representation when a candidate referent appears, then at test, they should prefer the object from the primed semantic neighborhood.
At 15 months, infants succeeded. In contrast, 12-month-olds did not succeed on this task even after a full week of vocabulary training designed to boost the effect of priming.
It is possible then that 12-month-olds’ representations of novel nouns’ meaning are not yet sufficiently rich (if any at all) to guide their choice of referent when one does appear.
Together, these findings suggest that the capacity to establish a representation of a novel noun’s meaning in the absence of any visible referent and use this representation later to identify a candidate referent object emerges between 12 and 15 months.
