Thirty years ago, psychologist Steven Jay Lynn held the popular belief that hypnosis could improve memory.
“People thought that hypnosis was analogous to a truth pill that people swallowed and that whatever they re-called afterward would be accurate,” says Lynn, who this summer was named distinguished professor of psychology at Binghamton University. In fact, many state court systems permitted trial witnesses to testify after their memories were “refreshed” with hypnosis. Then Lynn and others began to test that theory.
Bit by bit they punctured it. Lynn’s lab was one of the first to investigate how hypnosis affects memory. In nearly two decades of work, the lab has repeatedly turned up evidence of hypnosis’ unreliability as a recall tool.
Lynn says that two findings stand out. “First, hypnosis increases inaccurate memories,” he says. It boosts the quantity of information reported by test subjects, but also causes more recall errors and more false memories. “Second, people who are hypnotized often report that they are more confident in their inaccurate memories than people who try to recall the same things but were not hypnotized in advance.”
Lynn and his colleagues construct ingenious tests to see how hypnosis impacts memories.
In one test, subjects were warned in advance that hypnosis could create false memories. Subjects were asked to remember a recent night they had slept through without interruption. They were then hypnotized and asked if they recalled hearing a loud noise at 4 a.m. on that night. Even though they were warned, and previously reported they slept through the night, more than a quarter of subjects reported that they were awakened by a loud noise.
The lab’s findings ultimately helped to convince most state courts, as well as Canada’s federal court system, to ban the testimony of witnesses who experienced hypnosis for memory enhancement. But Lynn notes that after a person has been hypnotized, some states even ban testimony of memories that have not been hypnotically refreshed. “This position implies that all memories of a hypnotized person are somehow necessarily tainted. We doubt this is the case,” Lynn says. His lab is starting a new study to investigate the question.
His lab is also investigating whether training can increase people’s response to hypnosis. His research indicates that it can.
“Why is this important? First, hypnotic suggestibility is widely regarded as a stable trait, yet we showed that it can be substantially modified.” In addition, Lynn says, people who are highly susceptible to hypnotic suggestion may benefit more from clinical hypnosis, which is used for such things as weight loss and dealing with depression.
Expectations play heavily into a subject’s hypnotic experience, Lynn says. “What’s important are their attitudes, beliefs and expectancies about hypnosis.” It’s also important for them to actively participate in the suggested response. “A highly suggestible subject might actually lift the hand a bit voluntarily, at first, in response to a (hypnotic) suggestion for the hand to rise as if it is being pulled upward by a balloon. A low suggestible subject might simply wait passively for this to happen,” Lynn says.
“In the future, we hope to use brain-imaging techniques to see whether similar areas in the brain are activated in response to suggestion in people who have undergone [suggestibility] training compared with people who are highly suggestible yet have never undergone the training.”
Lynn’s interest in hypnosis began in college when he attended a workshop on the subject. “My earliest experiences set the stage for my later conviction that the study of hypnosis could help unravel some of the mysteries of human consciousness — how people process information, how expectancies and the power of imagination influence behavior and how people come to perceive their actions as involuntary and automatic. Today, I am dedicated to placing hypnosis on a scientific footing and to seeing that it has a firm place in the mainstream of scientific psychology.”