Eyes Behind the Lids

The Chicago Chamber

Eli: Late one December evening in 1951, an eight-year-old named Armond sat patiently on an Army cot in a lab at the University of Chicago. His father, Eugene Aserinsky, was a graduate student there under the sleep researcher Nathaniel Kleitman. As Smithsonian magazine tells it, he scrubbed the boy's scalp and the skin around his eyes with acetone, taped electrodes to his head and plugged the leads into a switch box over the bed. The recording machine was old. Aserinsky had restored it himself, and his son was its test run.

Mara: The question we were sent is short: why do we dream, and does it actually mean anything? Today's angle is tracking the science of dream meaning from sleeping eyes to waking emotions.

Eli: That boy on the cot is where the modern answer begins. From there it runs through a quarrel between the lab and the analyst's couch, a theory that dreams are static, and patients who simply stopped dreaming. One piece of it is still open.

Mara: The machine read two things. An electroencephalogram, sensors on the scalp tracing the brain's electrical rhythm. And leads by the eyes, catching every shift.

Eli: That night both traces pointed to wakefulness. The eye leads showed bursts, as if Armond's eyes were darting, and the brain trace looked like a boy wide awake. Aserinsky went in and found his son asleep, eyes closed. The worry was that an old machine was inventing signals, so he kept checking. Of one early session he later wrote: '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.'

Mara: Deaf to a voice, eyes busy, brain trace saying awake. Odd combination for sleep.

Eli: And the hunch hadn't come from nowhere. Before Armond, there were the babies.

Mara: Months of watching sleeping infants. Monotonous work. He saw their eyes move a lot, and each baby had a stretch of about twenty minutes with no eye movement at all, after which it usually woke. He used those stretches to nap, sure he'd miss nothing. And the pattern pushed him to measure eye motion with numbers. Those darting bursts are what we now call rapid eye movements, REM: quick, jerky shifts of both eyes together under closed lids.

Eli: So REM is the eyes sprinting while the sleeper stays out cold.

Mara: Sprinting, and the brain alongside. During those bursts the brain waves ran small, five to thirty microvolts, and irregular. He confirmed the eyes by peering at sleepers under a weak light he turned up gradually. He even brought in a blind undergraduate, who came with his guide dog. At one point in the night, the eye channels got a little more active.

Eli: Which leaves the real test: wake someone mid-burst and ask what was happening.

Mara: He and Kleitman did exactly that, and published in September 1953. Woken during the bursts, sleepers gave detailed dream recall twenty times out of twenty-seven. Woken while the eyes were still, nineteen out of twenty-three remembered nothing.

Eli: Something as private as a dream, turned into a tally on a chart.

Mara: And they read it big. The paper said the eyes, the brain waves, the body's automatic activity, 'and probably dreaming,' were very likely all one particular level of cortical activity, action in the brain's outer layer, in sleep. Aserinsky had gone looking for a mechanical record of moving eyes. The timing of those movements pushed science straight at what dreams contain. Whether eye movements could explain the experience of a dream, Eli, was a separate matter.

The Laboratory Versus the Couch

Eli: Aserinsky himself wasn't much interested in what dreams meant. His daughter put it plainly: 'He was a pure research scientist. It always irritated him when people wanted him to interpret their dreams.' He had little patience for Freud. Though he did wonder whether sleeping eyes were essentially watching a dream unfold.

Mara: Freud's big idea was wish fulfillment: hidden urges dressed up in symbols, so a dream disguises a secret want.

Eli: Freud called his dream theory his most valuable discovery. Dreams, to him, were symptoms of unconscious wishes, and reading them belonged in therapy.

Mara: And before REM, that was roughly the field. Scientific dream theories were mostly psychological. After it, the brain machinery came into view.

Eli: The machinery went further than theory. REM launched a branch of medicine for sleep disorders that afflict tens of millions of people. The eye readings from that Chicago lab ended up in clinics.

Mara: Freud's model had its own crack. The repeating nightmares of trauma don't look like disguised wishes. Even Freud recognized that.

Eli: So the dream moved from the couch to the chart. The chart couldn't say whether the story inside was a disguise, or just the noise of a busy brain.

Random Signals in the Brainstem

Mara: Here's the machinery the chart was picking up. In REM, brain waves run small and fast, the eyes dart and muscle tone drops away. That's muscle atonia: the body's movement largely switched off, so the sleeper doesn't act the dream out. Meanwhile the front of the brain, which helps check what's real, goes quiet while sensory and emotional regions stay active. That frontal shutdown may be why a dream's bizarre turns feel perfectly normal from inside.

Eli: That's the opening Allan Hobson and Robert McCarley took. In 1975 the two Harvard psychiatrists proposed that a dream's vivid imagery, its bizarre events, even how hard it is to remember, could come from REM chemistry: the ebb and flow of neurotransmitters like norepinephrine, serotonin and acetylcholine. In 1977 they published the model as activation-synthesis. The brainstem sends out random signals. The cortex, handed that static, synthesizes it into a story.

Mara: So the plot is the cortex making the best of noise. No hidden wish required.

Eli: Hobson called those signals a kind of physiological Rorschach test. G. William Domhoff explains dreams differently, through the brain's default network spinning out imaginations and simulations. But he agrees with Hobson on the point that matters: dreams have no adaptive biological function.

Mara: Back to Armond's chart, then. On this reading, the bursts Aserinsky caught belong to the machinery, and any dream riding on them is the cortex improvising.

Eli: What hadn't been measured was whether specific dream elements hold any significance beyond what the dreamer reads into them. If the brainstem writes the script, a dream has no author, and nothing in it to read.

The Forebrain Turn

Mara: The picture started to crack in the clinic. Mark Solms documented people with damage to the deep frontal pathways that carry dopamine. They stopped dreaming. Their REM sleep continued. Dreaming, as Solms's finding has been reported, turned out to depend 'not on the REM generator but on the motivational circuitry, the system that makes an animal seek and want.'

Eli: REM intact, dreams gone. The 1953 link between eyes and dreams, coming apart.

Mara: And it wasn't one patient. In 1973, nine people with schizophrenia who'd had a brain operation called leucotomy said they no longer dreamed. Researchers woke them from every REM period across two nights in the lab. Sixty-six awakenings. Two dream reports, both from the same person.

Eli: Two in sixty-six, from people whose sleep looked normal.

Mara: It runs the other way too. REM can happen without dreaming, and dreaming without REM. A 1962 study found mental activity after about three in four awakenings from non-REM sleep. Dreaming extends beyond REM, across a large share of the night. Some dissenters, psychoanalytic theorists among them, had long argued that different brain structures control the two. Most researchers, as of 2003, still said REM probably shapes dreaming and may help it along.

Eli: So the brainstem switch isn't the dream's engine. The forebrain's wanting system is.

Mara: That's what the lesion evidence shows: dreaming depends on forebrain dopamine pathways, not on an automatic output of the brainstem's REM switch. And what fills dreams has a pattern, with a name: the continuity hypothesis, the idea that the concerns people have in their dreams are the concerns they have awake. It's contested. Its backers, G. William Domhoff among them, say dream content reveals people's concerns rather than mapping neatly onto personality tests.

Eli: Robert Stickgold pushed that with Tetris. In 2000 he had healthy people play the game before sleep, and they reported dreaming about it. So did a group of people whose brain damage left them amnesic. They'd played too, and had no memory of playing. The falling blocks showed up anyway. The paper made the cover of Science. Stickgold's own line on it: 'I got a cover of Science magazine for the first published paper on dreaming in 40 years because I discovered that, and everybody already knew it!'

Mara: The amnesic players are the part that matters. The game got into their sleep without any memory of the game. Waking life reaches dreams by more than recollection, Eli, and what the dream does with it is the open part.

The Emotional Mirror

Eli: Stickgold's numbers say something about that. After playing during the day, about sixty percent of his players, woken as they drifted off, were seeing the game. One participant described 'seeing in my mind how the game pieces kind of float down and fit into the other pieces, and am also rotating them.' That's one strand of the adaptive reading Stickgold holds: dreaming does real work.

Mara: Which squares with the amnesic players: memory at work below conscious recall.

Eli: Revonsuo's version is threat simulation theory: dreams as nighttime rehearsals of danger, practice for survival responses. As the theory states it, dreaming about threatening events has a biological function. Another proposal is emotional. In REM, the brain may replay an event while weakening its original emotional charge, filing it with what it already knows. One review argues dreams can defuse traumatic memories when the brain's usual ways of regulating emotion and letting fear fade have been compromised by frightening events.

Mara: Here's where it gets stubborn. Whether dreaming itself has a vital function, separate from the sleep it happens in, is still unresolved. That same review found very little evidence that REM dreaming, as opposed to REM sleep, does memory work. The two are hard to pull apart.

Eli: So the adaptive case needs the dream, not just the sleep, to do the work.

Mara: That's where the other reading of the same evidence sits, Eli. Allan Hobson and G. William Domhoff see dreaming as a byproduct, with no survival value of its own. And on the strangeness, rivals agree. A researcher who disagrees with Hobson on much else reads bizarre dream twists as the limits of a sleeping mind. Hobson reads them as a kind of delirium, from the brain's chemistry in sleep. Neither finds hidden meaning there.

Eli: And the researchers who think content matters still won't hand anyone a dictionary. No one has established universal dream symbols. Antonio Zadra, who proposed a model of dream function with Stickgold, gave one interviewer this lesson, as she recalled it: 'we cannot interpret other people's dreams, only our own.' When he noticed water was a theme in two of her dreams, and one included flowing water, he suggested flowing water can be a metaphor for emotions.

Mara: Underneath it all, science still has no universal agreement on why people sleep, let alone why they dream.

Eli: So, why we dream: no one has proven that dreaming does a job the sleeping brain couldn't do without it. As for meaning, on the evidence so far it isn't a code. What fills a dream tracks the dreamer's own waking emotions and memories, built by the forebrain's wanting system rather than dealt out by brainstem static or a book of symbols.

Mara: Seventy-five years on, the darting eyes under Armond's lids mark a stage of sleep, not the dream's engine. The open part has signals to watch. Lucid dreamers, aware they're dreaming, steered in real time to test whether a conscious dream changes waking performance on its own. Lab work on whether recurring nightmares in people without PTSD trace to a specific chemical or nervous-system imbalance. Tracking how fear fades over one night of sleep versus several. And whether any dream symbol ever predicts the same thing across different people, without the dreamer's own account.

Eli: Listeners can look up rapid eye movement.

Mara: Follow science with us as researchers ask how the brain creates our dreams.

Eli: That's it for today. I'm Eli.

Mara: And I'm Mara. Thanks for listening, and until next time on Angle.