Lying is a relatively common behavior in children. But it does take effort – and quick thinking! Children learn to lie as young as 2, but it’s not till they are older that they learn to lie well.

It is around 6 or 7 years when we begin to see a shift – not just in a better understanding of social rules and how to interpret them; but also in an important cognitive skill known as working memory. Working memory is the ability to remember and process information.

In my research, I wanted to explore whether how working memory is related to lying. This is an important issue as lying involves keeping multiple pieces of information in mind in order to tell a successful lie. You have to remember what you said – what you think the other person knows – and what you what to tell them (the lie). And remember what you said when you are asked about it later!

So we designed this study looking at 6 and 7 year old children. We first tested their Working Memory by asking them how many things they could remember, like the letters that were presented on a computer screen.

Then we measured lying behavior using something called the temptation resistance paradigm. The goal here was to present a situation to the children that would be tempting. We asked the children a series of questions, like “What does a dog make?” and gave them a reward for every correct answer.

The final question was about a fake cartoon – What is the name of the character in Spaceboy? But before they can answer, we leave the room and tell them not to peek at the card.

Our results revealed 2 things:

1)       Children can’t resist to temptation to peek and lie about it!

All of the children who peek lied about it when asked, as we discovered when we checked our hidden cameras.

2)       Children with good working memory tell good lies

These children were able to mask their lies by making their guesses seem plausible, like "Oh it’s is my favorite cartoon, I watch it every Saturday.” However, those with poor Working Memory would often mumble something like, “I don’t know, I just thought of it.”

What does it mean for a parent?

The good news is that lying behavior decreases, as children get older. There is less social reinforcement for lying – on the playground for example. So take heart that is your child does lie, at least they are smart