Module 8. Sleep and Dreams

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8-1 What is sleep?

sleep periodic, natural loss of consciousness—as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation. (Adapted from Dement, 1999.)

Sleep—the irresistible tempter to whom we inevitably succumb. Sleep—the equalizer of presidents and peasants. Sleep—sweet, renewing, mysterious sleep. While sleeping, you may feel “dead to the world,” but you are not. Even when you are deeply asleep, your perceptual window is open a crack. You move around on your bed, but you manage not to fall out. The roar of my [ND] neighborhood garbage truck leaves my sleep undisturbed, but my baby’s cry interrupts it. The sound of your name can also cause your unconscious body to perk up. EEG recordings confirm that the brain’s auditory cortex responds to sound stimuli even during sleep (Kutas, 1990). And when you sleep, as when awake, you process most information outside your conscious awareness.

Now, by recording the brain waves and muscle movements of sleeping participants, and by observing and occasionally waking them, researchers are solving some of sleep’s deepest mysteries. Perhaps you can anticipate some of their discoveries. Are the following statements true or false?

  1. When people dream of performing some activity, their limbs often move in concert with the dream.

  2. Older adults sleep more than young adults.

  3. Sleepwalkers are acting out their dreams.

  4. Sleep experts recommend treating insomnia with an occasional sleeping pill.

  5. Some people dream every night; others seldom dream.

All these statements (adapted from Palladino & Carducci, 1983) are false. To see why, read on.

“I love to sleep. Do you? Isn’t it great? It really is the best of both worlds. You get to be alive and unconscious.”

Comedian Rita Rudner, 1993