Parents can be surprised to discover that preschoolers start to tell lies between two and four years old. When my preschooler accidentally breaks his toys, he has been known to say that a mouse did it.

Do you have a “mouse” in your house who breaks things, too? Like me, you might wonder how to help your children cultivate honesty as they get older.

Researchers recently investigated this with over 200 mostly white children from Montreal, Canada, who were between five and eight years old. They found that while kids can be easily tempted to dishonesty, there are simple ways to help them tell the truth even when it’s hard.

The children played a trivia game that gave them an opportunity for cheating. The researcher told the children that they could earn a prize if they correctly answered four multiple-choice questions, the first three of which had obvious answers—like “What kind of sweet liquid do bees make? Milk, maple syrup, cream, or honey?”

The last question, “What is the capital city of Amaro?,” was a trick question; it is a made-up country. Before the children could choose their answer, the researcher said she had to leave the room because she forgot something from the office. She told the children not to peek at the cards (which had the answers on the back) while she was gone. Unbeknownst to the kids, the researchers video-recorded them while they were alone in the room. After a minute, the researcher came back, asked the children if they had peeked at the cards, and then asked for their answer.

Overall, the majority of kids—61 percent—cheated by peeking at the trivia cards and 85 percent of those who peeked lied about it when asked if they did. But the researchers found that they could influence children’s honesty in two different ways.

Before playing the game, the researchers covertly modeled either lying or truth telling (and their consequences) for the children. After a researcher brought the children to the study room, a second researcher brought in supplies and left her glasses behind before she exited. The child witnessed the first researcher accidentally break the second researcher’s glasses, and then one of four scenarios unfolded:

The first researcher confessed the truth and had a positive experience with the other researcher, who said, “Thank you for telling me. That’s OK; it looks like they can be repaired.” The researcher also confessed but had a negative experience with the other researcher, who replied, “How could you do this? They are my only pair, and I can’t see without them! You have to buy me a new pair.” The researcher fibbed about breaking the glasses by saying she didn’t know where they were and had a positive experience with the other researcher, who said, “OK, thank you. I’ll keep looking.” The researcher lied but had a negative experience with the other researcher, who replied, “Hey, I don’t believe you—I see them. They’re broken! They are my only pair, and I can’t see without them! You have to buy me a new pair.”

In a fifth scenario, the second researcher returned and found her glasses, unbroken, as she left them (the control group).

Children who had witnessed the researcher have a positive experience after she confessed the truth or a negative experience after she lied (#1 or #4) were more likely to tell the truth about peeking in the game, compared to kids in the control group. And kids who witnessed the researcher have a negative experience after telling the truth or a positive experience after lying (#2 or #3) were just as likely to lie about peeking as kids in the control group.

The researchers explain, “Children may have used that [social] information in their analysis of the costs versus benefits of lying or telling the truth about their own transgressions.”

Another way that the researchers could influence children’s peeking was having them read stories about honesty and spend some time reflecting on them before playing the game.

Some of the children read stories about characters who either broke rules or caused damage to objects. Then, the characters either lied or told the truth about what they had done, were believed or not believed by other characters, and were either punished or not punished. The researchers then asked the children whether the characters told the truth, lied, or something else (to test for understanding).

For children who had read the stories, only 52 percent went on to peek in the trivia game, while 73 percent of the kids who didn’t read those stories first peeked.

The researchers explain, “It is possible that hearing the vignettes made the consequences of rule-breaking more salient to the children and led them to consider the consequences of their actions and resist temptation when they subsequently had the opportunity to commit a transgression in the [trivia game].”

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What do these findings mean for parents? Most kids have a hard time telling the truth. But seeing what a grown-up chooses to do (and what follows) can have some influence on what kids decide to do when they’re faced with a choice about honesty.

To be sure, kids have plenty of opportunities to watch as others are punished for lying. But what stands out from this study is that it’s also powerful if they see something positive happen to people who tell the truth.

As a parent, I’m reminded that my preschooler needs to see that happen in our family, too. When we accidentally break something at home, we can start off by thanking each other for telling the truth about what happened. In our own everyday behaviors, we can remember the big picture of what we want to teach our children about the meaning of honesty.