Scientists love to figure out what babies know, because it helps them understand what kinds of human knowledge are basically innate. What do we "know" about the world after just a few months of living in it?
Previous studies have found that infants know to be interested in the unusual: In a classic test, infants as young as a few months old are shown balls that appear to roll through walls, disappear behind them (or re-emerge as something else), or float in the air. Nonverbal babies may not fully understand the laws of physics, but they are more likely to stare at one of these logic-defying objects than ones that behave normally. This has always suggested to psychologists that infants have a richer understanding of the world than many give them credit for.
A new study published Thursday in Science took this theory a step further and showed that infants use their surprise as motivation to learn something new.
"We wanted to know why babies have this interest in surprising events," lead author and Johns Hopkins doctoral candidate Aimee E. Stahl told The Post. "Why does this surprise reaction occur? That's remained very mysterious, even though the reaction itself is so established."
According to her research, it may be that surprise acts as a learning aid, spurring a baby to test the unusual properties they've just seen in an object.
When Stahl and her co-author Lisa Feigenson, a professor of psychology and brain science at Hopkins, showed 11-month-old babies these "surprising" events, they seemed primed to learn more about the objects involved.
In one experiment, babies saw blocks and balls behaving in either expected or unexpected ways. Afterwards, they were more likely to pay attention to the object that had acted weirdly than they were a brand new object meant to distract them.
And the babies who'd been surprised were more likely to learn: They learned to associate a sound with the strange object (something tested by playing a sound while shaking the object, then testing how long the baby looked at the object when its token sound was played later, indicating recognition) while babies who'd seen the same object behaving normally didn't.
In another experiment, Stahl and Feigens0n showed that their adorable test subjects were running experiments of their own.
They looked for two common methods of object play: Banging the object against the high chair and dropping it onto the floor.
When babies saw a ball seemingly pass through a solid wall, they tested its solidity by banging it. When they saw an object float, they tested gravity by dropping it. They consistently used the appropriate "experiment" to test their object, and babies who hadn't seen them act unusually hardly ever used these "tests" while playing.
"When they witness an object defy expectations, they tailor their exploratory actions around that," Stahl said. "It was really specific and very selective."
So should you start defying gravity in an effort to make your kid a super genius? Stahl says this study doesn't show for certain that eliciting surprise is the best way to make a baby learn something new across the board. But it certainly suggests that infants do this themselves all the time. And further investigation of the behavior could help scientists understand how our way of understanding impossible things evolves throughout our lifetimes.
"Not only do babies have a really rich knowledge of the world, but they can harness it to test hypotheses," Stahl said. "When things don't go as predicted, that signals an opportunity to learn. That definitely raises some questions about whether you can use surprising things to shape infant learning. For now, we can say this: Babies let knowledge guide their behavior and exploration of the world just like adults do."
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