Once upon a time, someone came up with the idea of a fable — a fictional story which aims to teach the youngest among us one of life’s key lessons. And since then, we’ve had more fables than we can count, and the number and variety of their lessons are similarly hard to enumerate. But one thing that Aesop and others never taught us was how to test our theories using research panels, control groups, and replicable processes. And for generations, while we’ve assumed that kids learn morals from these stories, it turns out that there hasn’t been all that many studies to see if that’s true.

In 2014, though, a team of researchers decided to put a few of our stories to the test. The abstract is here, and in the end, Pinocchio’s nose grew, because it turns out, the “fact” that he teaches us something is mostly a lie.

The research team, led by Dr. Kang Lee of the University of Toronto’s Institute of Child Study, decided to focus on fables that aim to teach kids to tell the truth. They picked four parables: the Tortoise and the Hare, as a control — it’s not about honesty; Pinocchio; the Boy Who Cried Wolf; and the story of George Washington and the Cherry Tree. Each story was abridged significantly and to roughly the same length as the other three.

But before reading the stories to kids, the researchers needed to set up a situation ripe for dishonesty. Two test groups — one made up of three-year-olds, the other of seven-year-olds — sat down with a grown-up to play a game. The grown-up would have a toy (shielded from view) make a sound and have the kid guess what the toy was. But between rounds, the grown-up said that he or she had forgotten a storybook in the other room — and told the child not to peek at what the next toy was. Of course, some of the kids peeked.

When the tester returned to the room, he or she began by reading one of the four stories. Afterward, the tester asked the children if they had anything to confess — by citing to the main character in the story, as appropriate. SciLogs explains:

If the child had heard “The Boy Who Cried Wolf” or “Pinocchio,” the experimenter said to the child, “I’m going to ask you a question, and I don’t want you to be like the boy who cried wolf. I want you to tell me the truth, OK?” or “I’m going to ask you a question, and I don’t want you to be like Pinocchio. I want you to tell me the truth, OK?” After the participant agreed to tell the truth, she asked, “Did you turn around and peek at the toy when I left the room?”

A similar procedure was repeated for children who heard “George Washington and the Cherry Tree,” but here the experimenter told the children, “I’m going to ask you a question, and I want you to be like George Washington in the story. I want you to tell me the truth, OK? Did you turn around and peek at the toy when I left the room?”

Children who heard “The Tortoise and the Hare” were asked, “I am going to ask you a question, and I want you to tell me the truth, OK? Did you turn around and peek at the toy when I left the room?”

The results? Of the children who peeked and were read the Tortoise and the Hare — again, this is the control group — about 30% copped to their crime. And sadly for Pinocchio and the Boy Who Cried Wolf, the results for the questions involving them were about the same — only about one out of three cheaters admitted to cheating. But George Washington? He fared much better. About half of the kids who broke the rules decided that they, like Washington, cannot tell a lie. As Pacific Standard noted, “while hearing that tale produced only a modest improvement in honesty,” at least it had some impact; “the other two stories,” Pacific Standard points out, “had no impact whatsoever.”

Why? Huffington Post continues:

The researchers wondered about why the George Washington story had been so effective. [Or, more correctly, they wondered why it was the only one which was even marginally so.] One possible explanation was that the story had a positive outcome, with George Washington being rewarded for truth-telling, whereas the other two stories (Pinocchio or wolf) focused on the bad outcomes of lying. So the researchers decided to conduct a second experiment in which they modified the George Washington story. In this “negative” version, George Washington lies to his father by telling him that he did not cut down the cherry tree, but his father later on finds out the truth. As punishment for his lying, George’s father takes away George’s ax and tells him that he is very disappointed in him because he told a lie.

And once again, the “positive” story won out — or, rather, children once again failed to put the lesson from the “negative” story into practice. Only about 30% of those who peeked admitted to their wrongdoing.

So if you want to teach your kids a lesson, as Lee told the Telegraph, “emphasizing the positive outcomes of honesty rather than the negative consequences of dishonesty is the key.” Using the story of George Washington and the cherry tree may be a good tool — even if the story itself is a lie. (Shhh…)