There’s a very British shaking of heads going on around the Katie Holmes/Tom Cruise divorce story. Who could fall in with that Scientology lot in the first place? Well, look down the list of famous Scientologists on Wikipedia [2] and one thing jumps out: actors. A bizarrely large proportion of high profile followers of the cult tread the boards. What’s so special about actors? Well, one answer is that they are highly suggestible to hypnosis. Especially American actors.

I learned this yesterday as I sat through a three-hour tutorial at the Association for the Scientific Study of Consciousness [3] meeting in Brighton. It’s worth pointing out, for legal reasons, that the Church of Scientology officially looks down its nose at the use of hypnosis. But it’s also worth mentioning that L Ron Hubbard, the founder of Scientology, was an accomplished hypnotist [4].

According to yesterday’s tutor, Devin Terhune of Oxford University [5], hypnosis is an under-used tool in science. The idea is simple: if you can get people to behave in strange ways using only the power of suggestion, you can do it in ways that allow you to explore the fault lines of the brain that lead to conditions such as schizophrenia and obsessive-compulsive disorder.

Do it right, and you can make people unable to recognise themselves in a mirror - even when they hold up an object and see the person in the mirror holding it too. Thanks to hypnosis, you can induce obsessive-compulsive washing of hands by blocking people’s ability to “know” their hands are clean. You can make them enter synaesthesia, where sounds or letters are experienced as colours.

It has to be said, this approach doesn’t do anything for Terhune’s standing amongst his Oxford colleagues.  “You’re already dealing with strange phenomena,” he told us. “This just weakens your credibility.”

Nonetheless, he was encouraging the scientists in the room to consider taking it up.

Anyone can be a hypnotist, he says. The skill lies in weeding out the 85 to 90 per cent of people who aren’t highly suggestible; here’s what you need to know:

1. Forget spiralling black and white patterns, or pendulums. Visual imagery doesn’t help.

2. Suggestibility does not depend on gender, gullibility, naivete or intelligence.

3. If people are interested, co-operative, think hypnosis will help them or simply believe in magic, they are much more likely to succumb to your suggestion. A bit of alcohol helps, as does a quick snort of oxytocin, the naturally-occuring bonding chemical that increases trust.

4. Telling people to relax is unnecessary: in fact, it produces a decrease in suggestibility.

5. Use of the word “hypnosis” seems to be vital.

6. You can’t hypnotise people against their will.

7. A distaste for critical thinking is important in your subject.

8. Actors and drama students tend to be highly suggestible.

9. Americans tend to be more easily hypnotisable than the British.

10. If your subject is an American actor who is not known for critical thinking, you’re golden.