Are we all just puppets on a string? Most people would like to assume that they are free agents – their fate lies in their own hands. But they’d be wrong. Often, we are as helpless as a marionette, being jerked about by someone else’s subtle influence. Without even feeling the tug, we do their bidding – while believing that it was our idea all along.

“What we’re finding more and more in psychology is that lots of the decisions we make are influenced by things we are not aware of,” says Jay Olson at McGill University in Quebec, Canada – who recently created an ingenious experiment showing just how easily we are manipulated by the gentlest persuasion. The question is, can we learn to spot those tricks, and how can we use them to our own advantage?

Olson has spent a lifetime exploring the subtle ways of tricking people’s perception, and it all began with magic. “I started magic tricks when I was five and performing when I was seven,” he says.

As an undergraduate in psychology, he found the new understanding of the mind often chimed with the skills he had learnt with his hobby. “Lots of what they said about attention and memory were just what magicians had been saying in a different way,” he says.

One card trick, in particular, captured his imagination as he set about his research. It involved flicking through a deck in front of an audience member, who is asked to pick a card randomly. Unknown to the volunteer, he already worked out which card they would choose, allowing him to reach into his pocket and pluck the exact card they had named – much to the astonishment of the crowd.

You can see a video of Olson blowing his volunteers’ minds below: