Is being selfish a character flaw, or is it programmed into some people's DNA? Scientists were curious about this so they decided to scan the brains of people who scored high in Machiavellianism while playing a basic trust game. They wanted to see if there were individuals who would exploit others' willingness to play fair and cooperate for individual gain.

The team of scientists found that an increase in Machiavellian scores happen when people are imagining ways to exploit the situation for their own benefit.


Participants were given a set amount of money and allowed to decide how much they wanted to invest in their anonymous partner participant. Their partners were actually a pre-programmed computer that decided how much of their investment to return to the participant. But when it came to their turn, they were allowed to either punish their partner's unfairness or reciprocate their cooperation from earlier by giving them more money.


Those with high Machiavellian scores wound up having the most money. They did not reciprocate cooperative exchanges. The study believes that Machiavellians constantly monitor the behavior of others in social situations in order to come out on top.