When you hear the word hypnosis, you may picture the mysterious hypnotist figure popularized in movies, comic books and television. This ominous, goateed man waves a pocket watch back and forth, guiding his subject into a semi-sleep, zombi-like state. Once hypnotized, the subject is compelled to obey, no matter how strange or immoral the request. Muttering "Yes, master," the subject does the hypnotist's evil bidding.

Our understanding of hypnosis has advanced a great deal in the past century, but the phenomenon is still a mystery of sorts. In this article, we'll look at some popular theories of hypnosis and explore the various ways hypnotists put their art to work.

People have been pondering and arguing over hypnosis for more than 200 years, but science has yet to fully explain how it actually happens. We see what a person does under hypnosis, but it isn't clear why he or she does it. This puzzle is really a small piece in a much bigger puzzle: how the human mind works. It's unlikely that scientists will arrive at a definitive explanation of the mind in the foreseeable future, so it's a good bet hypnosis will remain something of a mystery as well.

But psychiatrists do understand the general characteristics of hypnosis, and they have some model of how it works. It is a trance state characterized by extreme suggestibility, relaxation and heightened imagination. It's not really like sleep, because the subject is alert the whole time. It is most often compared to daydreaming, or the feeling of "losing yourself" in a book or movie. You are fully conscious, but you tune out most of the stimuli around you. You focus intently on the subject at hand, to the near exclusion of any other thought.

Early Hypnohistory

People have been entering hypnotic-type trances for thousands and thousands of years; various forms of meditation play an important role in many cultures' religion.

In conventional hypnosis, you approach the suggestions of the hypnotist, or your own ideas, as if they were reality. If the hypnotist suggests that your tongue has swollen up to twice its size, you'll feel a sensation in your mouth and you may have trouble talking. If the hypnotist suggests that you are drinking a chocolate milkshake, you'll taste the milkshake and feel it cooling your mouth and throat. If the hypnotist suggests that you are afraid, you may feel panicky or start to sweat. But the entire time, you are aware that it's all imaginary. Essentially, you're "playing pretend" on an intense level, as kids do.

In this special mental state, people feel uninhibited and relaxed. Presumably, this is because they tune out the worries and doubts that normally keep their actions in check. You might experience the same feeling while watching a movie: As you get engrossed in the plot, worries about your job, family, etc. fade away, until all you're thinking about is what's up on the screen. A hypnotist can't get you to do anything you don't want to do.