If you’ve ever had trouble telling the truth, that’s because lying may actually be impulsive. A study led by Ming Hsu at the University of California, Berkeley’s Haas School of Business found that the brain’s prefrontal cortex is linked to how we control self-interest in group settings.

"Obviously, the prefrontal cortex has many different functions. One of the functions is to allow us to inhibit self-interested motives, and to sort of function in a group setting where you can’t just satisfy your self-interest, but you have to trade off a very large set of norms that the society as a group has agreed upon, so whether it’s honesty, whether it’s fairness, whether it’s reciprocity."

Hsu says this explains why our impulses, especially in children, are often at odds with societal norms of honesty.

"We have to remember that the prefrontal cortex is the last of the brain regions to fully mature, so it has a lot of interesting implications about why do adolescents commit the most number of crime and what can we do about it?"