The Natural History of Dreaming; How Long Do Dreams Last?

The idea that time may be dramatically distorted when dreaming, or even reversed, was given support in 1861 in Maury's book Sleep and Dreams. Maury gave an account of a dream he had about the French Revolution, and the reign of terror that followed it. In the dream he was a participant, as a prisoner, of a revolutionary tribunal whose judges included Marat and Robespierre. After being tried and sentenced to death he was taken to be guillotined in front of a large crowd. He dreamt of the actual execution, including his head being separated from his body, and then abruptly woke to find that the headboard of his bed had fallen and struck him on the back of the neck in the same place as the guillotine in the dream. The only rational explanation was that the stimulus of being struck must have initiated the whole dream sequence, which although apparently very lengthy must have proceeded fast enough to fit in between the blow on the neck and waking up.

The notion that dreams are fleeting impressions formed immediately before waking is still fairly prevalent. In the Hull survey, one of the statements that respondents were invited to comment on was 'Dreams occur only in the few moments before you wake up'. Of the 149 respondents, 18 endorsed this statement and 23 thought it may be true. Some of those who thought the statement was true may have had very few experiences of extended dreams, and for them dreaming may actually have consisted of recollections of thoughts or images that had occurred immediately before waking up. Others may genuinely have believed that even lengthy dreams had been compressed into a brief period.

In the 1950s, William Dement conducted a number of experiments to establish the extent to which subjects lost track of time during REM sleep (Dement and Kleitman, 1957; Dement and Wolpert, 1958). In the first of these, reports of dreams were elicited from subjects woken from REM sleep on a total of 126 occasions. As a rough estimate of the amount of dreaming that had been going on, they counted the number of words used by subjects to describe their dream. The longer the REM sleep period before the awakening, the larger the number of words the subjects tended to use. In another experiment, the subjects were woken either five minutes or 15 minutes after REM sleep had started and asked to estimate which of the two periods applied in their case. They were correct 92 times out of 111, indicating very good awareness of the amount of time that had elapsed.

A third, and crucially important, experiment involved the use of external stimuli to influence the content of dreams. Dement and Wolpert (1958) used a pure tone stimulus, light flashes and a water spray on an exposed part of the body, and found that the water spray was most effective in influencing the content of dreams (although this stimulus also tended to wake the subjects up!) Here is one of their examples:

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S was sleeping on his back. It was a hot summer night, and he was completely uncovered. An eye-movement period started, and after 5min. cold water was sprayed on his feet and legs. One minute later he was awakened. The first part of the dream involved being in a room talking to some friends. Then, 'two children came into the room and came over to me asking for water. I had a glass of ice water and I tipped the glass to give it to them. I was sitting, and I spilled the water on myself. The children wanted the ice and tried to grab it, but it slipped away. I got mad, because they were so greedy, and tried to shove them away from the chair. Then I got out of the chair and was going to change my pants. As I left the room I seemed to be in a school and I saw many children in the hall and I seemed to be late for a class. I was starting to climb up some stairs when the bell rang'. (Ibid.)

They sprayed the subjects with cold water when they were undoubtedly in REM sleep, and then woke them after varying intervals of a few minutes. Ten of the subjects (like the one above) had unambiguous accounts of cold water in their dreams, and these subjects' dream reports showed a very good correlation (in terms of the time that the action in the dream would have taken since the cold water spray) with the actual time that had elapsed.

Despite Maury's odd experience with his French revolution dream, it seems that dreams proceed at a normal temporal pace. Perhaps Maury had not been completely woken up by the failing headboard, and had dreamt some of his dream with the headboard lying on him. It seems likely that our dreams are attempts to make sense of experiences that are vivid but inconsequential (as suggested by John Hughlings Jackson in his perceptual release theory, developed by J. L. West (1962) to account for the generation of hallucinations and dreams), and this will be dealt with later in the chapter. Maury's dream could be a good example of an attempt at comprehending a series of striking bat unconnected images and sensations, a form of the 'effort after meaning' that the Cambridge psychologist, Sir Frederick Bartlett, ascribed to normal Braking memory processes, in the first half of the twentieth century.