Abduction is surely a strange phenomenon, and from what I've read (both Dr. Mack's books, and two from psychologist David Jacobs; each takes a different side of the "Aliens: good or evil" debate).. uh, where was I? Well from what I've read, the experiences are very real to the experiencers, many of whom have been able to remember details without hypnosis.
But, and this is where things get mighty fudgy, in several instances, it appears that something akin to "the spirit body" is what gets abducted.. there isn't a lot of attestation for that one, but it's something that makes you think, "this is even weirder than I thought!" People have been observed to be *in their rooms, in a catatonic like trance* during an abduction that they then describe in great detail.
But the opposite is true also, that people have been abducted and also reported *out* of their rooms during the time frame.
A famous case involves an abduction witnessed by a New York City policeman and several other witnesses, who saw the body of a man float *through* his wall and up into a waiting UFO..
Strange strange strange.. it seems the abduction phenomena asks us to believe several things at once that we aren't prepared to believe. As a society, I mean.
As to what the mechanism is, who knows.. that beam of light has been seen lifting cows and, get this, Bigfoots too!
But to the purpose, you have Mack's theory that "the awakening of consciousness" is what is at the root of it, and then you have Jacob's theory that the aliens are only using us as a "farm" for DNA, and have been for centuries.
Alternatively, perhaps they just *like* doing it..