You know that old nursery rhyme that says that children are made of "sugar and spice and everything nice?"

Well, maybe not.

"People think kids are these wonderful creatures who are loving and kid and hugging everyone. And they are," said Harvard Business School professor Michael Norton, co-author of Happy Money: The Science of Smarter Spending. "But I have four older siblings, so I know kids are not always hugging and smiling and nice."

That's why Norton wanted to re-examine one theory of how children learn moral behavior, which says that morality comes with age. His hunch was that it might be a little bit more complicated than that. 

"We really wanted to study this idea that maybe as we get older, it's not like we learn to be a different type of  moral person. We learn that other people are watching us and that's what really changes whether we're nice or not," he said.

To do that, he launched a study of children between the ages of 5-12, and had them choose between either a flashy highlighter or a boring pencil. They could either make their choice immediately and get the prize, or go into a room and do a coin toss, and let the coin decide.

Naturally, a coin toss would give them a 50/50 chance of getting the highlighter. But what the study found was that the coin toss "chose" the highlighter 60 to 90 percent of the time, suggesting that the children were fudging the results to get the better prize.

"There's one view that we learn how to be moral over time, that people understand social norms and things," Norton explained.

"This suggests we don't know how to be moral, we learn how to appear to be normal, and every time we can get away with it we'll fudge things to get what we really want," he continued.  

Listen to the full Boston Public Radio segment with Michael Norton above.