Kids Start To Test Surprising Claims By Early Elementary School

As many families prepare for a visit from Santa, some are facing questions about the jolly old man in the red suit.

The fact that children will (sometimes) accept counterintuitive claims, like the existence of Santa Claus or the Tooth Fairy, has led some theorists to marvel at their willingness to take others at their word.

"Child brains are gullible," writes Richard Dawkins, "open to almost any suggestion, vulnerable to subversion...wide open to mental infections that adults might brush off without effort."

But research in developmental psychology tells a different tale. By age 5, children are harder to dupe about the existence of a fantastical creature without some good evidence that the creature really exists; by age 8 or 9, if not sooner, children reject the reality of Santa.

In short, children don't just soak up what they're told: They integrate what they hear with other sources of evidence, and they take into account the reliability and expertise of the informant. But these are abilities that develop over time, and children must learn to coordinate them with other activities, like asking questions and making their own observations. In fact, as children learn and mature, they don't simply become more critical consumers of what others say, they also learn how to seek out the evidence that will allow them to test surprising claims.

That's the core finding from a new paper forthcoming in the journal Developmental Psychology, authored by psychologists Samuel Ronfard, Eve Chen, and Paul Harris. In the paper, Ronfard and colleagues investigated how children respond to a counterintuitive claim — and in particular, whether they would go on to deliberately test a claim from an adult when it conflicted with their prior expectations. They call this kind of testing the "empirical stance," and they find that it's evident by elementary school.

The participants in Ronfard and colleagues' study were nearly 200 children, ages 3 to 8, recruited from Chinese schools. Each child was first presented with an unfamiliar set of five objects that varied in size. The objects were created by painting nesting Russian dolls white and mounting them onto square bases. Because the objects were of the same shape and visibly made from the same materials, it was natural for children to assume that the smallest was the lightest, and the largest the heaviest. So not surprisingly, when an adult asked which object was heaviest, the vast majority responded by saying that the largest object was the heaviest.

But the adult then did one of two things. The adult either echoed this claim — that the largest was the heaviest — or offered a counterintuitive claim, that the smallest was the heaviest. The researchers were interested in whether hearing this counterintuitive testimony would be enough for children to change their minds, and whether they would go on to test the adult's claim by picking up the various objects to compare their weights.

Children did initially seem to take adults at their word: Only 13 percent of preschool kids and 8 percent of elementary-school kids continued to insist that the biggest doll was the heaviest after the adult stated that the smallest was the heaviest. But once the adult left the room and the children were allowed to explore the objects themselves, an interesting pattern emerged: The elementary school kids who had received the counterintuitive claim went on to systematically test it by picking up the smallest and largest objects. The other kids explored the objects, too, but not in a way that was so clearly directed towards confirming or falsifying the adult's claim.

The weight of the dolls was actually what one would expect: The largest doll was the heaviest. So even though the majority of children endorsed the adult's counterintuitive (and false!) claim after it was offered, exploring the dolls had the potential to generate evidence that the adult was wrong. And this evidence was sufficient for kids to reject what the adult had claimed: When children were asked a final time which doll was heaviest, those who had systematically explored the dolls by picking up the smallest and the largest were significantly more likely to reject the adult's counterintuitive claim than to accept it.

As a whole, these results suggest that children are willing to trust an adult who offers counterintuitive testimony, but their acceptance is provisional. By elementary school, they go on to systematically test a claim that they find counterintuitive by acquiring new evidence, and they use that new evidence to update their beliefs. It's still unclear how broadly this finding applies — for instance, whether children are equally likely to apply the empirical stance across different contexts, cultures, and for different kinds of claims.

When it comes to integrating multiple sources of evidence, including what we've been told, our current beliefs about the world, and the evidence before us, Santa isn't all that special. Most of us accept the reality of electrons based on what we've read or heard, rather than based on what we've personally inferred from experience. For many people, belief in God or angels is similarly based on the testimony of others. And for some, political claims are accepted because they are the norm within their communities; they never receive serious scrutiny.

So while children may have something to learn from adults when it comes to Santa Claus or the Tooth Fairy, adults might similarly have something to learn from elementary school children: Most of us would do well to adopt an empirical stance more often than we do.

Tania Lombrozo is a psychology professor at the University of California, Berkeley. She writes about psychology, cognitive science and philosophy, with occasional forays into parenting and veganism. You can keep up with more of what she is thinking on Twitter: @TaniaLombrozo

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