Many people are reluctant to accept psychic phenomena because they're convinced that stage magic and mentalist tricks can produce the same effects. The usual comeback is that psi phenomena have been tested under controlled conditions that preclude cheating. But there's another way of addressing this concern. Magicians and mentalists, as talented as they may be, are sometimes credited with greater powers than they possess.
Take the 1947 film noir Nightmare Alley. Based on a novel by William Lindsay Gresham, Nightmare Alley is the story of a carnival barker who becomes a mentalist's assistant. He rises rapidly into the big time, eventually acquiring a reputation as a medium and "miracle worker." His fall is equally rapid, though he is redeemed in a tacked-on happy ending reportedly added at the studio's insistence.
It's a strange film – a B-movie plot produced on an A-movie budget, and starring matinée idol Tyrone Power, who's surprisingly effective playing against type. If you have a Netflix account, you can watch it on your computer via their "Watch Instantly" feature.
Along the way, the film purports to show us the tricks used by fake psychics and mediums. Some of these scenes are pretty accurate. There's a good example of cold reading in a scene between Tyrone Power and a skeptical police officer, and a good illustration of a mentalist's "warm" reading spiel (in which generalities that could apply to anyone are passed off as spirit messages). But at other times, the mentalist's art is greatly exaggerated for dramatic effect.
Early in the film, we learn that a female mentalist and her assistant have developed an elaborate code that allows them to communicate during their act. The assistant holds up an item presented by someone in the audience, and the blindfolded mentalist identifies it. The secret of the trick lies in the assistant's choice of words and manner of inflection. Different combinations of words and emphases mean different things: pocket watch, locket, handkerchief, etc.
So far, so good. Such codes really are used by mentalists. Harry Houdini and his wife Bess used such a code in an early mind-reading act, and their code became the basis for Houdini's alleged message from beyond the grave.
But before long, the filmmakers get a little carried away with themselves, and the code miraculously becomes capable of communicating lengthy messages verbatim. In one scene, the blindfolded Tyrone Power (who by now has acquired the code) is asked about the contents of a note written by someone in the audience. Standing some yards from the audience member, with no possibility of reading the note even if he is peeking under his blindfold, he nevertheless manages to reel off the entire message. "Word for word!" the excited sitter confirms.
Needless to say, the brief utterances of Power's assistant could not possibly have encrypted the entire message "word for word."
In the same scene, a skeptical sitter tests Power by inquiring about the health of her mother. In actuality her mother is dead. Power realizes it's a trap, and surprises the skeptic by saying that her mother has passed on. Later, when she asks him in private how he knew, he says vaguely that it just seemed like a trick question. Realistically, there's no normal way he could have known this. Still blindfolded, he couldn't see her face, and she never spoke; the assistant did the talking.
Popular culture continues to showcase the abilities of phony mind-readers in shows like Psych and the upcoming series The Mentalist. For entertainment purposes, the hero's abilities are often expanded to unrealistic dimensions – as are the abilities of mediums in shows like Medium and Ghost Whisperer, for that matter.
It's all in good fun, but viewers beware: in real life, neither mentalists nor mediums are as impressive as their Hollywood incarnations.