Lucid dreaming verified by volitional communication during REM sleep

Lucid dreaming verified by volitional communication during REM sleep, by Stephen LaBerge, Lynne Nagel, William Dement and Vincent Zarcone, published in Perceptual and Motor Skills volume 52 in 1981, is the study that first established lucid dreaming as an objectively verifiable physiological state rather than only a reported subjective experience, by having a sleeping subject signal a predetermined eye movement pattern, detectable on polygraph, at the moment they became aware they were dreaming. Its strength is the method itself, a signal that could be timestamped against the sleep laboratory's own recordings, converting a first person report into evidence a third party could check. Its limit is that the study establishes the timing and physiological reality of the state, not any claim about what a dreamer can achieve or perceive while lucid, so a claim about lucid dreaming's further uses rests on separate and later research, not on this founding demonstration.