In the 1930s, Dr. Loyd W. Rowland hypnotized several people and convinced them to touch an angry rattlesnake. In another experiment, he had them throw sulphuric acid in his face. His findings warned of the dangers of hypnosis — that it could be used to persuade normal people into hurting themselves and others.

Hugh Davis, the curator of a local zoo, was the snake handler for the study.

The two experiments, which took place at the University of Tulsa, Oklahoma, appeared in the Journal of Abnormal and Social Psychology in January 1939. The report drew criticism and kicked off a controversial series of experiments testing the limits of what a person can and cannot be made to do under hypnosis.

Dr. Rowland borrowed a diamondback rattlesnake from a nearby zoo and placed it in a box with the help of Hugh Davis, a professional handler (learn more about Hugh Davis's extraordinary life here).

Dr. Loyd W. Rowland 

Dr. Rowland kept the box in a hot room for three days until the snake “became very lively.” The snake was also prodded with a wire to incite aggression.

 “The result was a most frightful scene,” Dr. Rowland noted. “The snake invariably wound himself into a coil with his head lifted ready to strike, his rattles singing loudly enough that they could be heard within a radius of 100 feet.”

Four people took part in the study. Each subject was hypnotized before they were brought to the laboratory.

He told the first two subjects that there was a “rubber coil” in the box and asked them to pick it up. In reality, an invisible sheet of glass prevented each subject from touching the snake.

The first subject, a junior student at the university, reached her hand in and touched the glass. In looking for an opening, she nearly pushed the glass in and had to be stopped by the experimenter. The second subject, the captain of the university football team, went to the box, saw the snake, and woke up. Dr. Rowland noted the subject did not seem deeply hypnotized from the beginning.

The next two subjects were told there was a dangerous rattlesnake in the box and were also asked to pick it up. A graduate student from the university went to the box and reached inside, touching the glass. The second subject did the same thing and, after touching the glass, became confused. She “took two steps back from the box and stood, apparently uncertain as to what next to do.”

Dr. Rowland tried the same procedure with 42 subjects not under hypnosis. He found that, “all the persons were not only frightened at the appearance of the snake, but would not come close to the box; only a few were persuaded finally to pick up a yard stick and touch the snake. They all seemed bewildered when they touched the glass which they could not see.”

There was one exception. A young woman thought the animal was fake. She reached inside and touched the glass. After learning the snake was real, she became very afraid and from that point on would not go near the box.

Dr. Rowland concluded that individuals under deep hypnosis can be convinced to perform actions that put them in serious danger. Does hypnosis also make them more willing to harm others? This was the topic of Dr. Rowland’s next study.

Dr. Rowland enlisted the help of two additional subjects to take part in a separate study, this one involving sulphuric acid. He hypnotized the first subject, a 16-year-old high school student, and brought her into the laboratory.

The subject watched as an assistant poured sulphuric acid into a glass. Next the assistant dipped some zinc in the acid. “The reaction was strong,” Dr. Rowland wrote, “with fumes steaming from the mouth of the glass.”

Dean Laurence S. McLeod served as Dr. Rowland's assistant.

The subject was warned that “sulphuric acid is very dangerous” and that it can “scar the skin and put out the eyes.” She was then instructed to throw the acid at Dr. Rowland’s face.

Not realizing there was invisible glass between her and Dr. Rowland, the subject hesitated. She grabbed the cup of acid but was reluctant to throw it. Urging her to continue, the assistant said, “I’m going to count to three and when I finish you will throw the acid. One, two, three.”

The subject threw the acid at Dr. Rowland. Immediately she was shaking and covering her face, as if she had made a terrible mistake. She was “very much disturbed.

The next subject, a male high school coach, was instructed to do the same. He hesitated a short while before throwing the acid “with such force that the acid spread all over the surface of the invisible glass.”

In both cases, Dr. Rowland would have been permanently marred, had there not been a glass shield. He concluded that hypnosis can make innocent people more easily persuaded to betray their better judgment and engage in dangerous behavior. For this reason, he warned hypnosis should be left to the professionals.

His findings challenged the widely held view at the time that hypnosis was safe and incapable of making subjects act against their will. It spurred a series of further experiments into the limits of hypnosis — some supporting and others contradicting Dr. Rowland’s alarming conclusion.

Several years after the publication of Dr. Rowland’s paper, psychologist Paul Young repeated the experiments with snakes and corrosive acid (nitric instead of sulphuric) and obtained a similar result. In another study, it was found that military personnel under hypnosis could be persuaded to give away government secrets and attack fellow soldiers.

Not all studies supported Dr. Rowland's conclusion. Milton Erickson from the University of Wisconsin reported failure in getting his hypnotized subjects to steal money. However, people under hypnosis will steal money, as long as they are first made to believe that the money belongs to them.

In 1965, Rowland’s snake and acid experiments were repeated for a third time, but with a markedly different conclusion. Two scientists at the University of Pennsylvania, Martin Orne and Frederick Evans, persuaded both hypnotized and unhypnotized subjects to touch the snake and throw the acid. They concluded that simply being part of the experiment made the subjects more trusting and willing to comply. Hypnosis had nothing to do with it.

So, where does that leave us? Can hypnosis really make you act against your will? Can it make you engage in dangerous or unethical behavior?

The position of most psychologists today is that hypnosis does not make someone more likely to engage in unethical or unlawful behavior, or do things against their will. Hypnosis increases a person’s openness to suggestion; however, if the hypnotist asks their subject to do something that goes against their values, the subject will likely refuse or, in a lot cases, they simply wake up (like subject #2 in the rattlesnake study).

There are exceptions. If the hypnotist changes the situation to make an unacceptable behavior seem acceptable, the subject will be more likely to comply. For instance, telling a hypnotized person that their money is in someone else’s pocket would allow them to take the money without realizing it's stealing.

Though rare, there have been reports of hypnosis being used for criminal activity. In 2016, an Ohio divorce attorney was sentenced to 12 years in prison after he used hypnosis to molest six of his clients. A similar case was brought against a physician assistant who hypnotized and sexually assaulted two of his patients in a Michigan clinic.

Cases like these suggest that hypnosis can lead people to act against their will — but these are exceptions, not the rule.

Read the original article here.