Using MRI technology, they discovered that people who cannot be hypnotized tend to have less activity in the parts of the brain related to attention and “executive control.” ... But those who could be hypnotized had more activity in the executive-control and salience networks.

Why is hypnosis not reliable?

Although there is a widespread belief that hypnosis produces accurate memories, researchers found that hypnosis does not work well as a memory-recovery method. In addition, people who have been hypnotized tend to feel confident that their memories are accurate, contributing to the persistence of false memories.

Does hypnotizing work on everyone?

Hypnosis isn't right for everyone, though. For example, you may not be able to enter a state of hypnosis fully enough to make it effective. Some therapists believe that the more likely you are to be hypnotized, the more likely it is that you'll benefit from hypnosis.