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Parents' Native Tongue Doesn't Color Infant Perception of Objects
Cambridge, Mass. - July 21, 2004 - Babies as young as five months old readily distinguish among items in ways that their parents do not, providing new evidence of how language shapes adult perception. The finding by Elizabeth S. Spelke, professor of psychology at Harvard University, and Susan J. Hespos, assistant professor of psychology at Vanderbilt University, appears in the July 22 issue of the journal Nature.
Previous studies have shown that adults categorize objects differently depending on what language they speak. Spelke and Hespos observed that five-month-old infants from English-speaking homes discriminate among objects in ways that are not typical among English-speaking adults.
"The languages of the world vary both in the sounds they require speakers to distinguish and in the meanings they require speakers to convey, and these differences influence what speakers of a language readily hear and think about," Spelke says. "Every time we talk about objects that come together, English speakers specify whether one object is in or on the other, while Korean speakers specify whether the objects fit tightly, like a cap on a pen, or loosely, like a book on a table."
Studies have shown that even when they aren't speaking, Americans are more sensitive than Koreans to the distinction between support and containment and Koreans are more sensitive to the distinction between tight-fitting and loose-fitting.
"Our research asked how these differences arise," Spelke says. "Does the experience of learning to speak English or Korean make you aware of the categories your language honors?"
Previous research on perception of the sounds of languages suggested otherwise. Infants are sensitive to the acoustic variations of all the world's languages, even those variations that their own language does not use and that the adults around them no longer hear. Hespos and Spelke were interested in finding out if a similar story holds for meanings: Are American infants, whose parents' language does not oblige them to distinguish tight-fitting from loose-fitting object relationships, more sensitive to that distinction than their parents are?
Spelke and Hespos tested whether five-month-old infants from native English-speaking homes detected noticed whether objects fit tightly or loosely. The tests were based on infants' tendency to look at events that they find to be novel and to look away when they get bored. Infants were shown an object being placed inside a container that fit it either tightly or loosely, until the time they looked at the event decreased, indicating that they were bored. They were then shown new tight- and loose-fit relationships. The researchers found that the babies looked at the objects longer when there was a change between tight or loose fit, illustrating that they were detecting the Korean concept.
Spelke and Hespos also conducted the experiment with adults, confirming past reports that English-speaking adults do not spontaneously notice the tight- versus loose-fit distinction.
"Adults ignore tight-fit versus loose-fit and pay attention to in versus on," Hespos says. "Adults glossed over the distinction that the babies detected."
"These findings suggest that humans possess a rich set of concepts before we learn language," Spelke adds. "Learning a particular language may lead us to favor some of these concepts over others, but the concepts already existed in us before we began to put them into words."
Spelke is co-director of Harvard's Mind/Brain/Behavior Initiative, and Hespos is a member of the Vanderbilt Kennedy Center for Research on Human Development and the Vanderbilt Vision Research Center. The research was supported by grants to Spelke from the National Institutes of Health.
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