This leads to an interesting idea -could some people be immune to some of the effects of magic? People who suffer from autism, for example, tend to have difficulties gauging facial cues, so their attention is less influenced by where somebody is looking. "You'd expect that somebody who suffered from autism would be more likely to spot the cigarette trick," agrees Kuhn.
The next step is to look at the brain directly. Working with psychologists Tim Hodson and Ben Parris at Exeter University's Centre for Cognitive Neuroscience, Kuhn plans to put people in functional magnetic resonance imaging machines to study which parts of the brain activate when they watch magic tricks.
"We're very interested in the part of the brain that detects cause and effect relations," says Parris.
In particular, the experiments will monitor the dorsal lateral pre-frontal cortex, which is known to be the bit of the brain that registers surprise, and the anterior cingulate, which is activated whenever something incongruous happens in our immediate environment.
Of course, magic is more than just surprise, so the researchers will be looking for something more. "When you're watching magic, there is just a split second when you're in disbelief and that's what we're looking for, that exact moment," he says. "The magic spot."
"No one's done this and it's unclear whether it'll be a single part of the brain or a network," says Parris.
But while psychologists slowly get to grips with the way magicians manage to trick our brains, is there not a risk that the magic will lose its power? That it will cease to be amazing? Wiseman thinks not. "What we get is a more informed audience," he says. "It's a little bit like juggling - you appreciate the juggler more once you've tried to juggle three balls and then you suddenly realise how hard it is to juggle seven."
The research will have benefits for the practitioners of magic, too. "What they will realise is that the human mind is a lot more fallible than we magicians expect," says Kuhn. "Maybe magicians are too careful in the way they conceal their secrets in front of an audience. They can probably get away with quite a bit more."