If an adult presents a preschooler with an object that looks like a key but calls it a spoon, will the child believe the grownup?

In almost two of three cases the answer will be "No" -- even among kids as young as 3, researchers report.

"Even preschoolers can evaluate whether other people know what they are talking about," concluded lead researcher Vikram Jaswal, an assistant professor of psychology at the University of Virginia in Charlottesville.

He said the findings support the notion that "kids aren't just passive sponges, soaking up any information that comes their way. They actually try and understand the incoming information in light of what they already know."

Jaswal presented the results this weekend at the American Psychological Society annual meeting, in Los Angeles.

Psychologists have long known that children gradually move from a sense of their own self or "mind" toward the idea that others think differently than they do, are motivated by their own needs, and can be fallible.

"At about 2, most kids are still grappling with their own sense of themselves," explained child psychology expert Susanne Denham, a professor of psychology at George Mason University, in Fairfax, Va. "As they get a little older, however, they begin to understand that others have their own mind, and can make mistakes."

But how adept are youngsters at catching others in a mistake?

In his study, Jaswal had adults rummaging through a box of objects to present 4-year-olds with an item that fell into a familiar category, such as "keys."

However, in some cases, the adult referred to the object as a "spoon" -- an item of a vaguely similar shape, but with a quite different function.

"So that's the conflict -- the speaker, an unfamiliar adult, has just called this object a spoon, but obviously it looks like a key. Kids could interpret this as an error on the speaker's part -- perhaps this person is just ignorant, or they didn't see it correctly," Jaswal said.

"And, in fact, that's what we find 4-year-olds are apt to do," he added. "They were actually pretty skeptical of this anomalous information, and accepted the information from the speaker only about 40 percent of the time. Many times they actually say things like 'Hey, that's not a spoon, that's a key!' pointing out the speaker's error."

Body language and other cues seemed to tip kids off that the adult might be less than reliable when it comes to the facts at hand. For example, if the adult was talking as he was rummaging through the box and looking away from the child, appearing distracted, the kid was much less likely to accept the notion that the key was, in fact, a spoon.

On the other hand, certain methods seemed to help adults persuade children that the key-like object was a spoon.

"When the speaker acknowledged that what he was going to say was unusual, by saying 'Hey, you're not going to believe this, but,' then acceptance rates doubled to about 87 percent," Jaswal said.

"It implies that the speaker has some 'special knowledge' that the child doesn't have," he added.

"In that sense, 4-year-olds, just like adults, are much more willing to go along with someone when they express some kind of confidence," the researcher said.

He said similar findings arose when the researchers tested 3-year-olds. The rate at which children expressed skepticism of adults fell sharply in children at or under 3 years of age, however.

Denham said the findings are in line with what is already known about the developing mind. "I myself have clear memories of my early childhood," she said, "and remember my grandmother telling me at dinner, when I was 2 or 3, that what I was eating was roast beef -- when it was actually turkey gizzards. I believed her. I probably wouldn't, though, in another year."

She agreed with Jaswal that young kids are already becoming adept at picking up on facial cues, body language and other stimuli that help determine whether someone else is confident in what they are saying, fudging things, guessing or outright lying.

"I think it shows a really clear and early ability to use social intelligence, to use information that another person is providing in order to filter out anomalous things," Jaswal said. This learning process can vary between kids, he added: "You do see some children who seem a bit more willing to go along with what's being said, while others are more skeptical."

The findings should help parents and other adults relax when it comes to responding to inquisitive tots, he said.

"When adults don't know the answer to something, they should make it clear that they don't know," Jaswal said. "They can still provide the child with an educated guess, of course, because it's more likely they still know better than their child does. Their answer could be marked with a qualifier, however -- 'I'm not sure, that's a great question, but I think'"

Of course, not every question demands a truthful answer, either, Denham pointed out.

"Something like Santa Claus, for example -- most of us wouldn't want to give the absolute truth to kids that young. That's case of something we call 'shared pretending,' where you and a child agree to a shared fantasy," she said. "It's part of the fun."