...a mental state (state theory) or set of attitudes and beliefs (non-state theory) usually induced by a procedure known as a hypnotic induction, which is commonly composed of a series of preliminary instructions and suggestions....
Contrary to a popular misconception - that hypnosis is a form of unconsciousness resembling sleep - contemporary research suggests that it is actually a wakeful state of focused attention and heightened suggestibility, with diminished peripheral awareness.
They also note as "criticism" of hypnosis that:
Skeptics point out the difficulty distinguishing between hypnosis and the placebo effect, proposing that hypnosis is so heavily reliant upon the effects of suggestion and belief that it would be hard to imagine how a credible placebo control could ever be devised for a hypnotism study.
It could be said that hypnotic suggestion is explicitly intended to make use of the placebo effect. For example, Irving Kirsch has proposed a definition of hypnosis as a "non-deceptive mega-placebo," i. e., a method which openly makes use of suggestion and employs methods to amplify its effects...
On PBS last night (at least in the Portland OR area) there was a program called "The Human Spark," in which it was asserted that humans have their unique capabilities because their brains are wired more towards social organization, abstraction in time and in considering others, and in imagination. Our brains are profoundly developed in these areas compared to other species (though they didn't mention dolphins).
Clearly both mindfulness and Zen meditation meditation and hypnosis have the effect of attenuating those areas in the brain doing this advanced human species stuff. As Petteri notes in a comment on my last post, though, in the cases of mindfulness and Zen meditation you are directing your mind, without preconceived expectations (if done correctly) whereas in the other case somebody's telling you, giving you cues, in effect, what you will experience.
Oh, but that's pretty much the same thing as a "guided meditation," isn't it? That, of course, is not the same thing as being given directions in how to meditate, which is what's in the Buddhist sutras - i.e., focusing on the breathing, mindfulness, etc. No, we're talking about things like, oh, "Now speak with the voice of non-duality." Yes indeedy, behavior and brain people think things like that, i.e., hypnosis, are a lot like a big ol' placebo. I for one can't discern a difference. BTW, one other nice thing about koan practice as well, is there's not really any cues given - there's no logic to the words of the damned koan, and yes indeed, in sanzen logical explanations aren't given any positive feedback.
And so, "guided meditation" as hypnosis is critique #501893 of "Big Mind": if someone's giving you cues as to what to expect, what to see, it's their production, and not even yours.
I don't think I answered all the questions in my last post, but at least I think I've outlined a bit of the answers, which, yeah, I know, Zen practitioners already know.