My worst nightmare

I used to work as a magician and occasionally performed in the US. On one trip I saw a gang of con artists performing the three-card trick on a New York street. I counted 13 members of the team, including people watching for police and stooges placing fake bets. Then I realised there were 14: my bag, containing my passport and money, had been stolen from between my feet. What did I learn? The three-card trick is like many areas of life - we all play a part.

Richard Wiseman is a psychologist at Hertfordshire University and carries out research into the psychology of deception.