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Baby face: Infants know who you are

WASHINGTON (CNN) -- Because of the way human brains develop, 6-month-old babies are better at recognizing certain faces than 9-month-old infants, a new study says.

Even more surprising, those 6-month-olds are also better than adults at some face recognition, it contends.

But there's a catch: It is non-human faces that the 6-month-olds excel at recognizing.

In a study detailed in Science magazine, researchers discovered that the 6-month-olds had no problem distinguishing between individual humans or between individual monkeys. But just three months later, at 9 months of age, while babies could still tell the difference between human faces, they couldn't tell one monkey from another.

"Early in development, the brain is open to any face," said Charles Nelson, a child psychologist at the University of Minnesota. But apparently sometime between 6 and 9 months of age, he said, babies' brains "key in" on the fact that human faces are the ones they need to pay attention to.

As people get older, they get better and better at detecting the subtle differences in the faces they see a lot: human faces, Nelson said. But at the same time, they lose the ability to detect differences in things they don't see a lot.

It's a phenomenon called "cognitive narrowing."

Olivier Pascalis, who led the study at the University of Sheffield in England, said a baby's brain gets "hard wired" during the first year of life, creating a template it can use to compare all those new human faces.

The researchers see a possible parallel between the development of face recognition and the development of speech. It may be that young children can learn a second language easier than adults because their brains are more open to new and different sounds, Nelson said.

The Science study involved 30 6-month-olds, 30 9-month olds, and 11 adults.

The babies, sitting on an adult's lap, looked at pictures of human and monkey faces. Researchers videotaped the children's eye movements, to gauge which picture they were focusing on, and for how long.

The longer they looked at a picture, the less familiar to them it was considered to be, because babies of any age -- as well as adults -- will look longer at the picture that is new, or unfamiliar.

Participants were first shown identical pictures, either of a monkey or a human. Then, they were shown one of those original pictures again, plus a new photo.

When looking at the monkey pictures, the 6-month-olds spent more time looking at the new picture. But the nine-month-olds, as well as the adults, split their time fairly evenly looking at the two monkey faces -- meaning, the researchers said, that they didn't recall seeing one of the monkey faces earlier.

Those in every age group could recognize humans faces they had seen before.




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