So begins the 1951 British Pathé short film profiling the work of hypnotist Peter Casson. This question—whether hypnosis is genuinely harmful or some kind of fiction—has plagued the topic ever since the 18th century, when Franz Mesmer claimed he could affect cures by controlling the magnetic streams in the human body. By the mid-20th century, the claims of mesmeric magnetism had disappeared, but people in theaters across Britain were still falling into a trance, this time under the influence of stage hypnotists like Casson:

Casson was particularly famous because some years earlier, in 1946, the BBC had invited him to their studios at Alexandra Palace to be interviewed. They conducted a test of Casson’s powers by having him hypnotize 12 volunteers. Six people fell under his spell and into a trance. But only five of them were from the original 12. The sixth person was an engineer from the BBC, watching the session on a monitor, across the corridor, in another room.

This led to a second experiment in which Casson attempted to hypnotize six people while they watched him on a television screen. Four of them fell asleep. Quite shaken by what they’d seen, the BBC put out a press release saying that they considered hypnotism too dangerous to broadcast. Current broadcasting standards still ban the initial hypnotic induction, in case, like those Alexandra Palace tests, it leads to viewers being hypnotized.

Theaters had no such qualms about putting hypnotism before the public. It was good box office, especially for Russian-born American Ralph Slater, who quickly became the most famous hypnotist in the UK. Slater was a short, sharp-suited figure with slicked-back hair and fashionably thin mustache. He debuted in London in 1948 as the world’s fastest hypnotist. He only had to put his hand on your head, and you would fall instantly asleep. Once in a hypnotic state, volunteers would brush imaginary ants off their clothes, play nonexistent musical instruments, and cry like a baby.

Slater also conducted an experiment in self-hypnosis in which he persuaded volunteers to run a lit match below their own outstretched hand. Rendered impervious to pain, volunteers didn’t feel the heat on their sooty fingers. Slater believed self-hypnosis could be used by the military to better endure the rigors of war. It was a remarkable demonstration and one captured on film by British Movietone:

Slater toured widely with his hypnotic shows and helped embed stage hypnosis in the public consciousness as some kind of awesome mental power capable of controlling minds. But just a year after the recording of the Movietone newsreel above, it all went wrong.

In March 1952, newspapers revealed that Ralph Slater was being sued for damages by a young woman, 23-year-old Diana Rains-Bath. She had volunteered for one of Slater’s performances several years earlier at the Brighton Hippodrome. Slater, in the name of entertainment, had made her cry on stage, one of his signature stunts. Like Casson, he used posthypnotic commands, this time making Rains-Bath shout “Peanuts!” every time Slater stamped his foot. What seemed fun in the theater turned to misery at home when the woman became subject to fits of depression and weeping.

The case came to court. Dr. Van Pelt, president of the British Society of Medical Hypnotists and who had treated the woman for depression, acted as a prosecution witness, alleging that her participation in Slater’s show led directly to her illness. Perhaps to sow seeds of doubt in the minds of the jury, or genuinely fearful that the hypnotist’s presence would further affect their client’s well-being, the prosecution asked Slater not to look directly at the woman while in court.

Slater defended himself and spoke of the benefits of hypnosis. He was actually a staunch promoter of its therapeutic value. Slater claimed he had cured a cripple and had someone else throw away their spectacles after attending his shows. He said that none of the 25,000-plus people he had hypnotized over the years had ever displayed any adverse effects.

The trial lasted three days, but it took only an hour for the jury to decide that the young woman’s condition was a result of Slater’s performance. They awarded her $1,000 in damages. In an appeal, the damages—not the charge—were rescinded. But by this time, Slater’s bookings were drying up. His work permit wasn’t renewed, and he was forced to leave the country and return to the United States, where he tried to rebuild his career as a stage hypnotist.

Ralph Slater, stage hypnotist. Credit: Wellcome Library

Hypnosis has always been a tricky subject to define. Broadly speaking, there are two different scientific views on what hypnosis is. Some believe it is an altered state of mind in which people respond to suggestions, whether it’s to cry like a baby or become numb to pain. In this theory, hypnosis is a physiological process that scientists can attempt to measure using brain scans and other tools.

But there is another theory, explained to me many years ago by psychologist Graham Wagstaff at the University of Liverpool. I was making a documentary about hypnosis for Channel 4 at that time, and Wagstaff told me that back when he was a student in the 1970s, he had taken part in a hypnotic demonstration of sorts.

It took place on a Tyne Tees programme called The Amazing World of Kreskin. A mentalist by profession, Kreskin began his performance by openly declaring that he did not believe hypnosis existed. Instead, he talked about “suggestion,” which he explained, somewhat vaguely, as a misdirection of the mind and proceeded to give a demonstration using some volunteers from the audience.

One of those volunteers was Graham Wagstaff. Within seconds, Kreskin’s volunteers were doing all the crazy kind of antics you’d expect to see in a stage hypnosis show, including jumping from their chair whenever Kreskin clicked his fingers. After the show, one of Wagstaff’s friends asked him about the experience. Wagstaff revealed that the suggestion hadn’t really worked for him, so, not to upset Kreskin’s performance, he just played along. His friend turned to him and said something that shaped Wagstaff’s future: “How do you know everyone else wasn’t just playing along?”

Wagstaff is now one of the leading experts on the non-state theory of hypnosis, sometimes referred to as social compliance. This theory argues that there is no physiological state of hypnosis. No trance. And that hypnosis cannot in any direct way alter memory or the senses. Hypnosis works because people believe it works, and, in the case of stage hypnosis, volunteers enter an imaginative role-play with the performer. If true, where does that leave the Ralph Slater case?

Even among stage hypnotists, opinion is divided between believers in the state and non-state theories. One of the latter explained to me that stage hypnotism is a matter of finding the right volunteers. It’s a self-selecting process. You don’t go to a hypnotism show if don’t already think it’s possible. You don’t volunteer to go on stage if you don’t think it’s going to work. After that, it’s a matter of casting for the different roles the volunteers will take in the show and making sure the wrong kind of volunteers—the ones who will be immediately spotted by the audience as attention seekers—are sent back to their seats. He summed it up by saying, “There are two kinds of people in the world. People who watch soap operas like Coronation Street and the people who watch fantasy shows like Star Trek. I’m looking for the people who watch Star Trek.”

It wasn’t long after the Ralph Slater verdict that the British Parliament passed the 1952 Hypnotism Act. It began, some months before Slater came to trial, as an attempt to ban the public performance of hypnotism entirely while safeguarding the work of hypnotherapists. Dr. Van Belt was one of those consulted on the bill, and he sincerely believed that hypnosis should be left to the medical profession. However, the bill was amended on its passage through Parliament and ultimately did nothing except oblige stage hypnotists to avoid using anyone under the age of 21 in their performance and to obtain a license from the local authority whenever they wanted to put on a show.

The bill has subsequently been amended further to reduce the minimum age of the volunteer to 18. And government advice to local authorities is that stage hypnotists cannot include any demonstration that is likely to cause harm, anxiety, or stress. Cures and pain-blocking demonstrations, like those given by Ralph Slater, are also ruled out. Other than that, stage hypnotists are free to carry on making people cry, eat onions while believing they are apples, and flail their arms about while plagued by imaginary flies.

Regulations for stage hypnosis vary around the world. It is banned entirely in several countries — like Israel, Belgium, and Denmark — but hypnotists can work in most parts of the world if they follow local government or state regulations. Perhaps more surprisingly, hypnotherapy is largely self-regulated (or “unregulated,” as Wikipedia has it) through multiple competing organizations. Anyone can take a hypnotherapy course accredited by one of the organizations and set up a practice, sometimes in as little as a couple months.

Last year, Amnesty International in the Netherlands featured hypnotherapist Jos Claus in its “Through the Eyes of a Refugee” campaign. Claus hypnotized people into believing they were undergoing the traumatic journey of a refugee. Volunteers shook, cried, and screamed as they imagined shootings, bombs, suffocation, and finding the dismembered bodies of their loved ones. Finally, woken from hypnosis, the volunteers met the real refugee whose life they had just relived. It’s an emotional demonstration and one that a stage hypnotist would not be allowed to carry out in the UK.

Claus doesn’t confine his work to hypnotherapy, as shown by videos of his more entertaining work on YouTube. Here, you can see Claus working a party where his volunteers eat lemons, get drunk on water, and brush away imaginary insects—all similar to routines made famous in the UK by Casson and Slater nearly 70 years ago.

Hypnosis hit the headlines again in 2011, this time at North Port High School in Sarasota, Florida. Three students died within weeks of each other. Marcus Freeman, a promising football quarterback, died in a car crash. Wesley McKinley and Brittanny Palumbo both committed suicide. This unfortunate string of events might have been put down to bad luck or coincidence, but instead it was put down to hypnosis.

Freeman had been trying to use self-hypnosis to dull the pain from a dental visit on March 15, 2011. His girlfriend reported that he had a strange look in his eyes as he got into the car that day. His car, with both of them in it, later careered off the road before hitting a tree. She survived the crash; Freeman did not. He’d been taught self-hypnosis by high school principal George Kenney, who had also hypnotized McKinley and Palumbo, the two other pupils who died.

Kenney admitted to using hypnosis to help students deal with anxiety. He was charged with two misdemeanors, including practicing hypnotism without a license. A plea deal meant that he served a year on probation and exited the teaching profession. However, because the original case never went to trial, the position of therapeutic hypnosis was never dealt with. A year later, the three families of the deceased won a wrongful death suit against the school board and were awarded $200,000 each. Kenney is said to have hypnotized more than 70 pupils at the school.

Self-hypnosis is used to manage anxiety, sleep problems, pain, and many other common issues. But at the end of 2017, Samsung came up with another use for self-hypnosis. Why not use it to erase the memory of your favorite TV shows so you can enjoy them all over again? The company unveiled a website called Unspoil Me. I can’t promise it works, and you’ll have to accept the terms and conditions acknowledging that hypnosis has real effects and that you are over the age of 18 and have no known neurological conditions. After that, you’re free to listen to Swedish hypnotist Fredrik Praesto wipe your memory with soothing words and an endlessly spinning pattern.

Just two years after British Pathé asked if hypnosis was a menace or a myth, Stanley Milgram conducted some experiments in obedience that also shed light on hypnotic phenomena. In a groundbreaking psychological experiment at Yale University, Milgram asked ordinary people to electrocute human subjects in the name of science. And they did, seemingly subjecting them to enormous pain. What the people didn’t know is that the experiment was bogus. The electrocuted subjects were actors. There were no harmful shocks of electricity. Why did these ordinary people electrocute someone simply because they were asked? They did it simply because a man in a white lab coat asked them to.

Milgram was trying to find answers that explained the German people’s response to Hitler in the 1930s. Why were so many people drawn to such dark deeds? The conclusion of the experiment was that it doesn’t take much to persuade people to do out-of-the-ordinary things. All you need is the right context, the right motivation, and an authority figure. The people in this experiment thought they were taking part in a legitimate exercise. They simply followed the orders of a scientist, a man they chose to respect.

Milgram believed that, as individuals, we readily conform to group behavior, and in doing so we give up responsibility for our actions to the figure in authority. Given the sadistic nature of the task the people undertook, it was an unwelcome finding. At some level, most of us can be influenced to do things that seem out of character if the circumstances are right.

Time, I think, for a hypnotic experiment. Actually this is what professionals call a pseudo-hypnotic experiment. And it uses a hypnotic disc. The idea of a whirling pattern that can induce a self-hypnotic state goes back to the early 20th century and has since become something of a cliché. A magician named Jerry Andrus did, however, discover a whirling disc that has some surprising effects when you gaze at its centre. Assuming that you made it through Unspoil Me and the Milgram experiment unscathed, let me introduce you to Andrus’ remarkable trick. I promise you will experience something wonderful. The experience takes less than two minutes. Just click on the video, follow the instructions, and prepare to be amazed by this weird trick of the mind.