Excerpt from The Mind at Night by Andrea Rock, plus links to reviews, author biography & more

Nor was there any significant effect on dream content from presleep experiences, such as serving sleepers banana cream pie or pepperoni pizza right before bedtime, depriving them of fluids to see whether they had persistent dreams of being thirsty, or showing them violent or erotic films. Dreaming brains appeared to be fiercely independent directors, relying on some yet-to-be-deciphered criteria for selecting characters, setting, and plot in their nightly internal dramas.

Other experimenters proved that even those who claim not to dream do in fact concoct dream scenarios throughout the night. If awakened while REM is still in progress, subjects remember their dreams, but if they are awakened several minutes after REM has ended, the memory of the dream typically vanishes. Yet another study probed whether dreams are different at different points in the night and found that dreams early in the night revolved around current events in the dreamer’s life while, as the night progressed, dreams incorporated more events and characters from the past.

Did the jerky eye movements of REM sleep indicate sleepers were following the action in the dream as they would images on a movie screen? Early experiments by Dement suggested this was the case, but subsequent studies by other investigators found that eye movements did not in fact directly correspond to dream content.

One of the biggest preoccupations of the early researchers was understanding how visual imagery in dreams was produced, since the strongest sensory perception while dreaming is unquestionably visual. Investigations of dream content from the 1890s on consistently showed that nearly every dream contains visual imagery, while slightly more than half contain some auditory component. Among other sensations, touch or feelings of movement are present in less than 15 percent of dreams, while taste or smell rarely figure into dream experience at all.

One of the best-known experiments to test the source of visual imagery in dreams took place back where it had all begun, at the University of Chicago. After sleep research pioneer Nathaniel Kleitman retired, psychologist Allan Rechtschaffen used the lab before forming his own makeshift dream lab in an old gray-stone building around the corner from Abbott Hall. He ran cables from an EEG machine in his office to subjects who slept on foldout beds set up each night in other offices up and down the hallway after their occupants went home for the evening. Rechtschaffen created a lively atmosphere that encouraged rigorous but creative scientific thinking among the young researchers in his group. His wide-ranging curiosity and commitment to the highest scientific standards made him one of the most respected figures in the field. He was considered a tough reviewer for grant proposals or scientific papers, which made winning his approval all the more valuable. In the early days at his lab, young researchers often would come up with a new hypothesis about dreaming in the afternoon and test it that very night on the housewives and students who were paid to sleep while being recorded and periodically awakened--a process that went more smoothly with some than others.

"We once had a subject who was complaining about everything as we hooked him up to the EEG--he didn’t like the surroundings, the electrodes, the smell of the acetone," recalls Rechtschaffen. After the problematic student finally was prepped for the EEG and tucked into bed, Rechtschaffen and his assistant returned to the office where they monitored the EEG recordings. The assistant wryly speculated that after all the trouble the subject had put them through, he probably wouldn’t fall asleep. Unaware that the intercom to the sleeper’s room was switched on so that the young man in bed could hear every word they said, Rechtschaffen replied, "If he doesn’t fall asleep within two minutes, I’m going to electrocute him." With startling speed, the chronic complainer slid into stage I sleep.

From The Mind at Night, chapter 1, pages 1-16. Copyright 2004 by Andrea Rock. All rights reserved. No part of this book may be reproduced in any manner whatsoever, except for brief quotations embodied in critical articles with reviews, without written permission from the publisher, Basic Books.