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Wednesday, November 21, 2007

Babies Can Tell Friend From Foe



Babies Can Tell Friend From Foe
Researchers say infants make distinctions based on behaviors.

"I think it is the first study that demonstrated that very young infants show some understanding of social cooperation," said Tracy Dennis, an expert on child development and assistant professor of psychology at Hunter College in New York City. "This is an important study."

Previous studies had showed that babies prefer physically attractive people, but there has been no data on whether babies judge people based on how they behave.

"We know babies evaluate others based on outside stuff, not necessarily inside stuff," said study author Kiley Hamlin, a doctoral candidate in development psychology at Yale University in New Haven, Conn. "We wanted to see whether or not babies, like adults, have evaluative mechanisms for other people based on behavior."

Kiley and her co-authors (also her advisers) conducted a series of simple experiments to gauge whether 6- and 10-month-old infants preferred social individuals ("helpers") or anti-social individuals ("hinderers").

In one experiment, the infant watched a "climber" (basically a wood puppet with large eyes glued on to it) repeatedly try to climb a hill. On the third try, the climber was either given help or was pushed back down by a puppet.

The babies were then given the chance to choose (reach out and grasp) either the helper or hinderer puppet.

"Basically, we found very high rates of choosing of the helping character," Hamlin said.

One question is whether the babies are learning the behavior, or if it's something innate. The authors argue for the latter.
"Our results suggest that infants have a pretty advanced evaluating system that doesn't need much outside input to develop. It develops at a very early age, by 6 months," Hamlin said. "They are learning lots of stuff by 6 months, however, we know that it's incredibly unlikely that parents are explicitly teaching them anything about this. The fact that they can pick up on it by 6 months suggests that it's an important skill."

In fact, being able to distinguish between friend or foe could be an important survival skill. "It's important to tell who is going to be helpful, who is going to be threatening," Hamlin noted.

But that's the evolutionary argument, and not one everyone would agree with it, Dennis pointed out.

"Even though these authors make a good argument that very young infants don't have a lot of time to learn, even some basic observation of people cooperating might be enough to make some learning take place," Dennis said. "It's important, but it's a study that people are going to debate about."


journal Nature.
The infants watched a googly-eyed wooden toy trying to climb roller-coaster hills and then another googly-eyed toy come by and either help it over the mountain or push it backward. They then were presented with the toys to see which they would play with.
Nearly every baby picked the helpful toy over the bad one.
The babies also chose neutral toys _ ones that didn't help or hinder _ over the naughty ones. And the babies chose the helping toys over the neutral ones.
«It's incredibly impressive that babies can do this,» said study lead author Kiley Hamlin, a Yale psychology researcher. «It shows that we have these essential social skills occurring without much explicit teaching.
There was no difference in reaction between boys and girls, but when the researchers took away the large eyes that made the toys somewhat lifelike, the babies didn't show the same social judging skills, Hamlin said.
The choice of nice over naughty follows a school of thought that humans have some innate social abilities, not just those learned from their parents.
«We know that they're very, very social beings from very, very early on,» Hamlin said.
A study last year in Germany showed that babies as young as 18 months old overwhelmingly helped out when they could, such as by picking up toys that researchers dropped.
David Lewkowicz, a psychology professor at Florida Atlantic University in Boca Raton who wasn't part of the study, said the Yale research was intriguing. But he doesn't buy into the natural ability part. He said the behavior was learned, and that the new research doesn't prove otherwise.
«Infants acquire a great deal of social experience between birth and 6 months of age and thus the assumption that this kind of capacity does not require experience is simply unwarranted,» Lewkowicz told The Associated Press in an e-mail.
But the Yale team has other preliminary research that shows similar responses even in 3-month-olds.
Researchers also want to know if the behavior is limited to human infants. The Yale team is starting tests with monkeys, but has no results yet.

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