10/10/2014 03:44 pm ET Updated Oct 10, 2014

5-Year-Olds Usually Know If You're Lying, Study Says


Your kindergartener may not know that the tooth fairy isn't real or that cats -- sadly -- only have one life, but a new study shows that 5-year-olds are armed with a pretty mature critical thinking skill: They can tell when a person's lying, even if that person sounds confident.

Researchers at Concordia University and the University of British Columbia gathered 96 4- and 5-year-olds to see if they were able to tell when a person was lying. To do this, they showed the kids a series of short video clips featuring two people: one who spoke confidently but always lied and one who spoke hesitantly but consistently told the truth.

"Children have a bit of a reputation to be gullible, to believe everything we tell them, but that's not quite true," Dr. Patricia É. Brosseau-Liard, a Postdoctoral Fellow at Concordia University and co-author of the study, told The Huffington Post. "They are able to pick up on some cues and distinctions to know what to learn and what not to learn, so I was interested in investigating that a little more."

In the first set of videos Brosseau-Liard and her colleagues showed the children, both characters stated information about animals the kids were familiar with -- this way, the children would know if a person was lying, regardless of their tone.

The confident person would say something like, "whales live in the ground," while the hesitant person would say something like, "I guess whales live in the water?" Then, the children were shown videos about animals they weren't familiar with -- like, a pygmy sloth -- and the two characters would share information about these animals. The lying one continued to speak in a confident tone, and the truth-telling one continued to speak in a hesitant tone.

After various tests, it was clear that children of both ages generally preferred to trust information from a confident person, rather than a hesitant one. But since the confident person had previously lied, the 5-year-olds opted to trust the hesitant person who they'd seen tell the truth earlier when they couldn't verify a statement (like in the case of the pygmy sloth). These kids were able to use critical thinking skills to remember that the confident person was not to be trusted and were thus able to ignore the influence of that person's assurance.

The 4-year-olds, however, weren't able to put two and two together as easily, so results showed that they relied on a 50/50 chance to decide between the individuals.

"Perhaps it is that younger children are more in the moment, so to speak, so they may be more influenced by the immediately-available cue of confidence," Brosseau-Liard said. "As children get older, they become better capable to think about all of these different things at the same time."

It's quite convenient that kids take this cognitive leap at 5 years old, the very age they're sent off into the school system to enter kindergarten, where they face increasingly complex problems. This could be a result of the schooling itself, different parenting styles or cultural influences, but it's hard to tell, according to Brosseau-Liard.

That said, if 5-year-olds have the ability to critically think and are "not just sponges absorbing every piece of information that comes their way" (as Brosseau-Liard put it), keeping that cognitive development pattern in mind can still inform the way parents and educators interact with young kids.

"If they wish to help children realize which sources of information they shouldn't learn from, maybe they can help point out that some sources are good or bad," Brosseau-Liard said. "That helps children with these abilities that they already have."



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