1957 was a year of dreams and dreamers. Elvis hit the charts like a hurricane with Jailhouse Rock, Jack Kerouac published his Beat classic On The Road and Joanne Woodward won an Oscar for her role[s] in The Three Faces of Eve (see Thigpen & Cleckley). Meanwhile, a young preacher in Georgia, USA founded the Southern Christian Leadership Conference. His name was Martin Luther King.
Meanwhile, at the University of Chicago, Professor Nathaniel Kleitman was making breakthroughs in sleep research. He had already identified Rapid Eye Movement as an important phase in the sleep cycle. Now he recruited one of his students, William Dement, for the first truly "objective" study of dreaming - creating a sleep laboratory where participants would sleep wired to computers that measured their brain waves and eye movements. This is in contrast to older more subjective research into dreaming, like that carried out by Freud. Despite the laboratory setting, this was mostly a natural experiment; after all, Kleitman couldn't control when the sleepers would enter or leave REM sleep. One variable the researchers did control was the length of time they allowed REM to go on for before waking the sleeper and getting him or her to describe the dream.
Visit Mark Holah's site for an excellent summary of Dement & Kleitman's study, with quizzes and links.
Or if you prefer, Gary Sturt's website has a short summary
Find out about EEGs and brainwaves here
All the time the brain is buzzing with electricity and sends out "brain waves" that can be picked up by sensistive equipment. One device is the electro-encephalogram or EEG for short. This has dozens of electrodes that are fitted to the scalp and your brainwaves can be seen on a computer screen. Nathaniel Kleitman was one of the first people to use EEGs to record how brain waves change as we sleep.The EEG was also used in another of your core studies: Thigpen & Cleckley's study on multiple personalities.
When you are awake your brain waves are quite lively and this pattern is called BETA WAVES. As you get drowsy the waves become slower and more regular: these are ALPHA WAVES. When you fall asleep your brain waves slow down even more and become THETA WAVES. Stage 1 and Stage 2 of sleep are both light sleep when you can be woken very easily. Stage 3 and Stage 4 are deep sleep, when people are harder to wake and tend to be confused if they are awoken. This is the time when sleepwalking and sleeptalking happen and the brain produces very slow DELTA WAVES with a very big amplitude.
During a night's sleep we cycle down to Stage 4 then back into light sleep again, but instead of returning to Stage 1 we go into a stage called REM sleep, named after the Rapid Eye Movements that happen at this time. Suddenly the brain waves become very fast, like when you're awake, but your muscles are paralysed.
We go through this cycle of light sleep to deep sleep, then back to REM, then back to deep sleep again, several times a night. Each time we do it the deep sleep stage gets shorter and the REM stage gets longer. By the end of the night there is hardly any delta slep at all. We usually wake up straight after REM sleep or a period of light theta sleep.
Professor Kleitman and his student Eugene Aserinsky were the first people to link REM to dreaming in 1955. This time Dement & Kleitman wanted to confirm that REM was in fact dream sleep and also answer some other puzzling questions:
This is a natural experiment because the Independent Variables were naturally occurring:
It's also a lab experiment because the researchers did manipulate one set of variables:
Dement & Kleitman recruited 9 participants - 7 men and 2 women. Five were studied intensively and four were used as backups and to make sure at least some of the participans were getting unbroken sleep on a regular basis. The participants reported to the sleep lab just before their normal bedtime and agreed not to drink alcohol or caffeine during the day.
In the sleep lab the participants went to sleep while wired up to three machines. The EEG measured their brain waves. A group of electrodes attached around the eyes connected to the EOG (electro oculogram) and measured eye movements. Electrodes attachd to the arm connected to the EMG (electro myogram) which measured muscle tension.
Five or six times a night the sleeper was woken up by an alarm next to the bed. There was a microphone beside the bed and the participant would describe any dream they had been having into the mic then go back to sleep. The sleepers didn't know if they'd been woken in REM sleep or normal (NREM) sleep.
Participants had to describe three things about their dreams:
All participants had REM every night. REM lasted between 3 and 50 minutes (mean 20 minutes) and tended to get longer as the night progressed. On average, sleepers experienced REM every 92 minutes. If awakened during REM, they often went back into REM when they fell back asleep. REM was characterised by irregular eye movements and relatively fast brain wave patterns.
For all participants, there was a high degree of dream recall during REM. This ranged from participant KC who recalled dreams 90% of the time to participant DN, recalling dreams just 65%. Most of the times when no dreams were recalled in REM came from the early part of the night.
However, there were times when participants recalled dreams during NREM sleep, ranging from 12½% for DN down to just 3% for KC. Most of these were reported when participants were woken within 8 minutes of REM ending.
Some of the participants were very accurate at estimating how long their dream had lasted. Participant KC was right 7/7 times about the 5 minute dreams and 12/13 times for the 15 minute dreams. Participant DN was often right about the 5 minute dreams (8/10 times) but no better than guessed the 15 minute dreams (right 5/10 times). In general there was a high level of accuracy.
There did seem to be a link between the direction of the eye movements and the visual contents of dreams, as if the eyes moved towards what the dreamer was "looking at". Three dreamers with mostly vertical up-and-down eye movements reported dreams about looking up cliffs, climbing ladders and shooting basketball hoops. One dreamer with mainly horizontal side-to-side eye movements reported watching two people throwing tomatoes at each other
It seems as if dreaming is accompanied by REM activity. There were some exceptions to this, but it might just be that the memory of a dream lingers on once REM is finished.
It appears that there is a link between how long REM lasts and the subjective time that passes in the dream for the dreamer, though there are great individual variations here.
It looks at though the eye movements in REM correspond to what the dreamer is "looking at" in the dream.
Recording REMs during sleep seems to be an objective way of measuring dreaming.