Young infants have perceptual superpowers

baby in a superhero costume

SUPERBABE  Early in life, babies’ heightened senses help them make sense of the world.  


Young babies get a bad rap. They’re helpless, fickle and noisy. And even though they allegedly sleep for 16 hours a day, those hours come in 20-minute increments.

Yet hidden in the chaos of a young infant’s life are some truly magnificent skills — perceptual feats that put adults to shame. So next time your baby loses it because she can’t get her thumb into her mouth, keep in mind that her strengths lie elsewhere.

Photohunt masters

Six-month-old babies can spot subtle differences between two monkey faces easy as pie. But 9-month-olds — and adults — are blind to the differences. In a 2002 study of facial recognition, scientists pitted 30 6-month-old babies against 30 9-month-olds and 11 adults. First, the groups got familiar with a series of monkey and human faces that flashed on a screen. Then new faces showed up, interspersed with already familiar faces. The idea is that the babies would spend more time looking at new faces than ones they had already seen.

Adults and babies alike saw differences in these men’s faces. Six-month-olds could distinguish between the monkey faces, but 9-month-olds and adults struggled. O. Pascalis, M. de Haan and C. Nelson/Science 2002
When viewing human faces, all of the observers, babies and adults alike, did indeed spend more time looking at the new people, showing that they could easily pick out familiar human faces. But when it came to recognizing monkey faces, the youngsters blew the competition out of the water. Six-month-old babies recognized familiar monkey faces and stared at the newcomers longer. But both adults and 9-month-old babies were flummoxed, and looked at the new and familiar monkey faces for about the same amount of time.

Superior visual skills don’t apply to just faces, either. Three- to 4-month-old babies can see differences in lighting that are undetectable to adults. This ephemeral superskill evaporates just months later, scientists reported in December in Current Biology. To test babies’ visual acuity, researchers led by Jiale Yang of Chuo University in Tokyo first generated a series of 3-D pictures of snails. The shiny snails were made to look as though light was hitting them from different places. Like adults, 5- to 6-month-old babies couldn’t spot the lighting differences. But younger babies could, the team found.

With experience, babies probably learn that these subtle differences aren’t usually important. “As a result, infants lose this striking ability,” Yang says.

Hyper hearers

Young babies can pick up language distinctions that baffle adults. In some of the earliest work on this, infant language expert Janet Werker of the University of British Columbia and colleagues found that 6- to 7-month-old babies raised in English-speaking households could detect differences in the Hindi language. For instance, the babies could tell apart two Hindi “ta” sounds that differ only in where the tongue sits when forming the sound, a distinction that eludes many nonnative speakers. In later studies, researchers found that this power of discrimination disappears during the first year of life.

Language doesn’t have to be spoken, either. In 2012, Werker and colleagues found that 4-month-old babies could discriminate between two American Sign Language handshapes, whereas 14-month olds couldn’t.

 Touch detectors

Adults fall prey to a simple perceptual trick. When our arms are crossed, we often mistake which hand is getting touched. Our worldly experience tells us that a touch on the left side of our body usually means our left hand was touched (but when our arms are crossed, our right hand is there instead). Young babies are no such fools. Four-month-olds know which crossed foot actually got a tickle — they don’t get turned around like adults do. Just two months later, this precision is gone, scientists reported recently in Current Biology.

Infants younger than five months could easily tell these differently lit snails apart, whereas older babies and adults had trouble. J. Yang et al/Current Biology 2015

These powers seem diverse, but they all point toward an extremely detail-oriented little body. Babies don’t discriminate, these studies show. Instead, newborns take all-comers, collecting as much information as possible in a bid to make sense of the crazy world.

With age, we learn which signals are the most meaningful, a concept called “perceptual narrowing.”  As we get older, we stop paying attention to subtle differences in monkey faces and lighting, which usually aren’t relevant, but we get even better at spotting differences in people’s faces. And that makes sense: Our brains are sculpted to see, hear and feel sensations that are common, and meaningful, in our particular environment. And these infant superpowers are fascinating glimpses of that sculpting at work.  

Laura Sanders is the neuroscience writer. She holds a Ph.D. in molecular biology from the University of Southern California.

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