Aserinsky did a second nightlong sleep study of Armond with the same results—again the pens traced sharp jerky lines previously associated only with eye movements during wakefulness. As Aserinsky recruited other subjects, he was growing confident that his machine was not fabricating these phenomena, but could it be picking up activity from the nearby muscles of the inner ear? Was it possible the sleeping subjects were waking up but just not opening their eyes?
“In one of the earliest sleep sessions, I went into the sleep chamber and directly observed the eyes through the lids at the time that the sporadic eye movement deflections appeared on the polygraph record,” he would recall in 1996 in the Journal of the History of the Neurosciences. “The eyes were moving vigorously but the subject did not respond to my vocalization. There was no doubt whatsoever that the subject was asleep despite the EEG that suggested a waking state.”
By the spring of 1952, a “flabbergasted” Aserinsky was certain he had stumbled onto something new and unknown. “The question was, what was triggering these eye movements. What do they mean?” he recalled in a 1992 interview with the Journal of NIH Research. In the fall of 1952, he began a series of studies with a more reliable EEG machine, running more than 50 sleep sessions on some two dozen subjects. The charts confirmed his initial findings. He thought of calling the phenomena “jerky eye movements,” but decided against it. He didn’t want critics to ridicule his findings by playing off the word “jerk.”
Aserinsky went on to find that heart rates increased an average of 10 percent and respiration went up 20 percent during REM; the phase began a certain amount of time after the onset of sleep; and sleepers could have multiple periods of REM during the night. He linked REM interludes with increased body movement and particular brain waves that appear in waking. Most amazingly, by rousing people from sleep during REM periods, he found that rapid eye movements were correlated with the recall of dreams—with, as he noted in his dissertation, “remarkably vivid visual imagery.”
He later wrote, “The possibility that these eye movements might be associated with dreaming did not arise as a lightning stroke of insight. . . . An association of the eyes with dreaming is deeply ingrained in the unscientific literature and can be categorized as common knowledge. It was Edgar Allan Poe who anthropomorphized the raven, ‘and his eyes have all the seeming of a demon’s that is dreaming.’ ”