McGill researchers show how magicians sway decision-making

Jay Olson, a psychology major at McGill University in Quebec, Canada uses magic tricks to study perception, memory, and influence.

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.

The secret, apparently, is to linger on your chosen card as you riffle through the deck. (In our conversation, Olson wouldn’t divulge how he engineers that to happen, but others claim that folding the card very slightly seems to cause it to stick in sight.) Those few extra milliseconds mean that it sticks in the mind, causing the volunteer to pick it when they are pushed for a choice.

As a scientist, Olson’s first task was to formally test his success rate. He already knew he was pretty effective, but the results were truly staggering – Olson managed to direct 103 out of 105 of the participants.

Unsurprisingly, that alone has attracted a fair amount of media attention – but it was the next part of the study that was most surprising to Olson, since it shows us just how easily our mind is manipulated.

For instance, when he questioned the volunteers afterwards, he was shocked to find that 92% of the volunteers had absolutely no idea that they’d been manipulated and felt that they had been in complete control of their decisions. Even more surprisingly, a large proportion went as far as to make up imaginary reasons for their choice. “One person said ‘I chose the 10 of hearts because 10 is high number and I was thinking of hearts before the experiment started’,” says Olson – despite the fact that it was really Olson who’d made the decision. What’s more, Olson found that things like personality type didn’t seem to have much influence on how likely someone was to be influenced – we all seem equally vulnerable. Nor did the specific properties of the cards – the colour or number – seem to make success any less likely.

The hidden tricks of powerful persuasion