How does hypnosis work?

The power of suggestion during hypnosis is seen in many areas. Most notably in pain reduction when pain is reduced by suggestions of analgesia while people are hypnotised.

Hypnosis has helped people sleep better, stop smoking and even undergo dental treatment without pain.

But what is hypnosis and what goes on inside the brain of a hypnotised person?

As a result of the suggested obstruction the counting errors increased significantly but were the strongest in the group that were the easiest to hypnotise.

To answer these questions, researchers investigated the effects of suggestion on the processing of visual stimuli.

For this study, 60 participants with an average age of 23 years were divided into three groups: individuals who were very suggestible (susceptible to hypnosis), individuals of average suggestibility, and participants with low suggestibility.

Hypnosis was induced by a series of verbal instructions via an in-ear microphone by a trained hypnotist from outside the experimental chamber.

Under hypnosis the participants were shown a screen on which various symbols appeared such as triangles, circles and squares. At the same time they were also told that a wooden board was in front of their eyes obstructing their view. While they imagined the blockade they were asked to count the squares (which appeared at 10 per cent of the time along with circles).

As a result of the suggested obstruction the counting errors increased significantly but were the strongest in the group that were the easiest to hypnotise.

The participants were also linked to an electroencephalograph (EEG) to observe brain activity during hypnosis. At about 300-400 milliseconds after the presentation of the symbols to be counted, the neural processes that take place in the brain showed an extreme reduction.

However after approximately 100-200 milliseconds of the presentation there was no difference in the brain sensory processes which means that simple perception still takes place under hypnosis but deeper processing such as counting is greatly impaired.

The researchers were able to understand how hypnosis affects certain regions of the brain while it receives a visual stimulus.

This study shows that suggestion has a powerful impact on the brain and it responds by significantly modifying its sensory processes, especially during hypnosis.

Hypnosis is effective, as proven time and again through many studies and experiences, but now we are gaining a greater understanding of how it works in our brain.

Source: Scientific Reports