Magicians can make cards appear and people disappear. But the greatest trick any magician pulls off may be acquiring the knowledge needed to perform such acts in the first place.

After all, magic tricks are largely secrets; they wouldn't entertain audiences half as much otherwise. Thus magicians closely guard their trade's knowledge. And yet the craft would die if the techniques of magic did not transfer to promising practitioners.

"The paradox of all secrets, including those in magic, is that they are produced through concealing information, but for them to have any value, they also have to be shared to some extent," says Graham Jones, an assistant professor of anthropology at MIT, who has extensively studied the social world of magicians. "So there is a balance between concealment and revelation in the circulation of these tricks." More