New research provides evidence that the tendency to respond to hypnosis is linked to cognitive flexibility. The findings, recently published in Scientific Reports, indicate that people with higher levels of hypnotizability tend to be better at shifting between different mental sets.
Despite a growing interest in the clinical potential of hypnosis, little is known about its neurocognitive underpinnings. The authors of the new study were interested in how hypnotizability was related to executive functions and information processing.
“Throughout both my research and clinical work, I am particularly interested in understanding the cognitive and neural mechanisms that underlie therapeutic processes. Put differently, I work to investigate how, neurocognitively, interventions lead to improvement in symptoms,” explained study author Afik Faerman (@AfikFaerman), a PhD candidate at Palo Alto University.
“To do that, we need to explore how both the symptoms and the interventions manifest in the brain. Hypnosis is a good model of such interventions because it serves as a great nonpharmacological alternative to several psychological and medical symptoms; however, it seems not everyone benefits equally from hypnosis. In my research with Dr. David Spiegel at Stanford University, we are interested in understanding why some individuals benefit more than others, and what we can do to improve its effectiveness for those who benefit less.”
The researchers first had 545 prospective participants complete the Harvard Group Scale of Hypnotic Susceptibility. Of this initial sample, 72 participants were selected for having particularly high and particularly low scores on the test of hypnotizability.
The selected participants then completed two neuropsychological tests: the Wisconsin Card Sorting Test and Trails Making Test. Both tests were used to assess a cognitive phenomenon known as perseveration, meaning the tendency to apply previously learned (but incorrect) logical rules after being presented with new (correct) rules.
“We found an association between people’s ability to respond to suggestions in hypnosis (i.e., hypnotizability or hypnotic suggestibility) and how easy it is for them to shift between different cognitive sets (less perseveration). “This provides behavioral evidence for a potential shared mechanism between hypnotizability and executive functions,” Faerman told PsyPost.
“Practically, the more hypnotizable one is, the easier it was for them to drop an old rule system and transition to a new rule system. While there is a need for further evidence to substantiate this, some might interpret our findings as increased cognitive flexibility.”
The researchers had also predicted that hypnotizability would be associated with faster performance on simple attention tasks and with slower performance on more complex cognitive tasks. However, the results from the neuropsychological tests showed no evidence of this.
“There is no consensus in the literature yet about the neurocognitive mechanisms of hypnotizability, and there is still much to be done to better understand them. It is also possible that high hypnotizability and low hypnotizability are distinct in more aspects than just hypnotizability. Our sample was not appropriate to test that. Future research should recruit balanced representations of high, medium, and low hypnotizable participants,” Faerman said.
Previous research has used functional magnetic resonance imaging to identify several brain regions with altered activity and connectivity during the hypnotic state. In particular, scientists observed decrease in activity in the dorsal anterior cingulate, an increase in connectivity between the dorsolateral prefrontal cortex and the insula, and reduced connectivity between the dorsolateral prefrontal cortex and the default mode network.
But there is still much to learn about the brain mechanisms underlying hypnosis.
“Coupling behavioral performance with neuroimaging can shed more light on the neurocognitive mechanism at play in hypnotizability. When we have targets for neural mechanisms, we can try to modulate them to improve the effects of hypnosis,” Faerman said.
“In fact, we recently succeeded in doing that; we temporarily increased hypnotizability by using non-invasive brain stimulation of a neurocognitive mechanism we identified using neuroimaging. The behavioral results of the current study support our choice of the neural target. The manuscript describing how we modulated hypnotizability is currently being finalized and will be submitted soon.”
“We are currently working to make hypnosis more accessible and affordable to as many individuals as we can,” Faerman added. “We are doing this by running a pilot study on the ability to use smartphone-based hypnosis, and we are seeing really encouraging results so far! If anyone is interested in learning more about what hypnosis is and feels like, they can download the app (“Reveri”) at the App Store or Google Play, or go to www.Reveri.com to have a no-cost interactive digital hypnosis experience. To participate in our study, please reach out to us at: OnlineHypnosisStudy@stanford.
The study, “Shared cognitive mechanisms of hypnotizability with executive functioning and information salience“, was published March 11, 2021.