The next major development came from behavioural psychology in American university research. Clark L. Hull (1884–1952), an eminent American psychologist, published the first major compilation of laboratory studies on hypnosis, Hypnosis & Suggestibility (1933), in which he proved that hypnosis and sleep had nothing in common. Hull published many quantitative findings from hypnosis and suggestion experiments and encouraged research by mainstream psychologists. Hull's behavioural psychology interpretation of hypnosis, emphasising conditioned reflexes, rivalled the Freudian psycho-dynamic interpretation which emphasised unconscious transference.
In as much as patients can throw themselves into the nervous sleep, and manifest all the usual phenomena of Mesmerism, through their own unaided efforts, as I have so repeatedly proved by causing them to maintain a steady fixed gaze at any point, concentrating their whole mental energies on the idea of the object looked at; or that the same may arise by the patient looking at the point of his own finger, or as the Magi of Persia and Yogi of India have practised for the last 2,400 years, for religious purposes, throwing themselves into their ecstatic trances by each maintaining a steady fixed gaze at the tip of his own nose; it is obvious that there is no need for an exoteric influence to produce the phenomena of Mesmerism. […] The great object in all these processes is to induce a habit of abstraction or concentration of attention, in which the subject is entirely absorbed with one idea, or train of ideas, whilst he is unconscious of, or indifferently conscious to, every other object, purpose, or action.
People have been entering into hypnotic-type trances for thousands of years. In many cultures and religions, it was regarded as a form of meditation. Modern day hypnosis, however, started in the late 18th century and was made popular by Franz Mesmer, a German physician who became known as the father of ‘modern hypnotism’. In fact, hypnosis used to be known as ‘Mesmerism’ as it was named after Mesmer.
In 1784, at the request of King Louis XVI, a Board of Inquiry started to investigate whether animal magnetism existed. Among the board members were founding father of modern chemistry Antoine Lavoisier, Benjamin Franklin, and an expert in pain control, Joseph-Ignace Guillotin. They investigated the practices of a disaffected student of Mesmer, one Charles d'Eslon (1750–1786), and though they concluded that Mesmer's results were valid, their placebo-controlled experiments using d'Eslon's methods convinced them that mesmerism was most likely due to belief and imagination rather than to an invisible energy ("animal magnetism") transmitted from the body of the mesmerist.
Stage hypnosis is a form of entertainment, traditionally employed in a club or theatre before an audience. Due to stage hypnotists' showmanship, many people believe that hypnosis is a form of mind control. Stage hypnotists typically attempt to hypnotise the entire audience and then select individuals who are "under" to come up on stage and perform embarrassing acts, while the audience watches. However, the effects of stage hypnosis are probably due to a combination of psychological factors, participant selection, suggestibility, physical manipulation, stagecraft, and trickery. The desire to be the centre of attention, having an excuse to violate their own fear suppressors, and the pressure to please are thought to convince subjects to "play along". Books by stage hypnotists sometimes explicitly describe the use of deception in their acts; for example, Ormond McGill's New Encyclopedia of Stage Hypnosis describes an entire "fake hypnosis" act that depends upon the use of private whispers throughout.
Changes in brain activity have been found in some studies of highly responsive hypnotic subjects. These changes vary depending upon the type of suggestions being given. The state of light to medium hypnosis, where the body undergoes physical and mental relaxation, is associated with a pattern mostly of alpha waves However, what these results indicate is unclear. They may indicate that suggestions genuinely produce changes in perception or experience that are not simply a result of imagination. However, in normal circumstances without hypnosis, the brain regions associated with motion detection are activated both when motion is seen and when motion is imagined, without any changes in the subjects' perception or experience. This may therefore indicate that highly suggestible hypnotic subjects are simply activating to a greater extent the areas of the brain used in imagination, without real perceptual changes. It is, however, premature to claim that hypnosis and meditation are mediated by similar brain systems and neural mechanisms.
We have, however, come a long way from the days of Mesmer’s animal magnetism. The increasing interest in mindfulness meditation suggests that mainstream acceptance of the mind-body connection is growing. This year, two well-received books by serious science journalists, Marchant’s Cure, out in January, and Erik Vance’s Suggestible You, out this month, explore this territory — the demonstrable results of hypnosis, faith, and even magic — long dismissed as pseudoscience or explained away as the placebo effect. Just last month, NPR reported that placebo pills work even when people know they’re taking a placebo. “Those are real, biological changes underlying those differences in your symptoms,” Marchant told Science of Us earlier this year. It’s all in your mind. But that doesn’t mean it’s not real.
In person, this looks strange enough. “There are a lot of ways to go into this state, but one way is to count to three,” Spiegel explains. “On one, you do one thing — look up. Two, two things — slowly close your eyes and take a deep breath. And three, three things — let the breath out, keep your eyes relaxed, and keep them closed. Let your body float. And then let one hand or the other float up in the air like a balloon.” When in this state, the hypnotized person’s hand will rise up into the air, as if on its own accord; Spiegel can reach over and gently pull the hand down, but it will float right back up again, as if it’s filled with helium.
Controversy surrounds the use of hypnotherapy to retrieve memories, especially those from early childhood or (supposed) past-lives. The American Medical Association and the American Psychological Association caution against recovered-memory therapy in cases of alleged childhood trauma, stating that "it is impossible, without corroborative evidence, to distinguish a true memory from a false one." Past life regression, meanwhile, is often viewed with skepticism.
Following the French committee's findings, Dugald Stewart, an influential academic philosopher of the "Scottish School of Common Sense", encouraged physicians in his Elements of the Philosophy of the Human Mind (1818) to salvage elements of Mesmerism by replacing the supernatural theory of "animal magnetism" with a new interpretation based upon "common sense" laws of physiology and psychology. Braid quotes the following passage from Stewart:
Since hypnotherapy is an adjunct form of therapy, used along with other forms of psychological or medical treatment, there are many applications. Hypnotherapy can be used to treat anxiety, phobias, substance abuse including tobacco, sexual dysfunction, undesirable spontaneous behaviors, and bad habits. It can be used to help improve sleep, learning disorders, communication, and relationship issues. Hypnotherapy can aid in pain management and help resolve medical conditions such as digestive disorders, skin issues, and gastrointestinal side effects of pregnancy and chemotherapy. It can also be used by dentists to help patients control their fears or to treat teeth grinding and other oral conditions.