Dreams and REM sleep

Much of the fascination with REM sleep is caused by its association with dreaming. Although people sometimes speak as if REM sleep is identical to dreaming, the reality is a bit more complicated than that. Even in the first observations by Aserinsky and Kieitman, the relationship was not perfect. In a review of 16 studies of this topic, Scientists found that dreaming was always reported more frequently after REM than after non-REM sleep. Typically, dreams were reported about 74% of the time after awakening from REM and 12% of the time after awakening from non-REM sleep. But precise estimates of the relationship varied.

Many of the differences in experimental opinion about the exact relationship can be attributed to the difficulty of deciding just what qualified as a dream. People usually will mumble something if you suddenly wake them up and ask what they were dreaming about. Most researchers specify some sort of coherent narrative as the critical characteristic of a dream, but differences in the application of this criterion have led to further differences of opinion about the precise relationship. In any case, it is clear that people are more likely to report a dream after being awakened from REM sleep than they are when awakened from any of the four non-REM stages.

There have been several studies of people who claim they rarely or never dreamed to see if they lack REM sleep. These self-proclaimed nondreamers not only showed the ordinary pattern of four to five REM periods per night, they also reported that they had been dreaming nearly half the times they were awakened from REM sleep. Thus, it seems clear that while some people have difficulty remembering their dreams, all people do dream.

Little is known about why everyone dreams or what dreams mean. Since earliest recorded history, people have tried to discover the meaning of their dreams. Babylonian records of dream interpretations date back to 5,000 years before Christ. Guides to the interpretations of dreams can be found in the Odyssey, The Talmud, the Old Testament-and at the checkout counter of your local supermarket.

Like the scholars and mystics who preceded them, psychologists have long been fascinated by this topic. In his first major book on psychoanalysis, Tbe Interpretation of Dreams, Sigmund Freud argued that dreams hold the key to understanding human motivation, because they express unconscious impulses that determine behavior. Unfortunately, however, the dreamer's desires are usually disguised and hidden in cryptic symbolism. Freud and his followers have devoted considerable effort to decoding dreams according to their psychoanalytic theory.

In one dream, which Freud analyzed in his book, a young doctor dreamed that tax officials questioned his return, even though he had reported his income honestly. Freud interpreted this as a sign that the doctor unconsciously wanted to make more money; thus, his dreaming mind had created tax collectors who refused to believe how modest his income was.

Researchers have found Freud's theory of dreams difficult to test scientifically, in part because the interpretation of each dream requires judgment by a trained psychoanalyst. In general, there is good evidence that Freud was correct when he argued that dreams can reveal important issues in a person's life. However, they seem to do so more directly than Freud believed. "There is no rationale for approaching a dream as if it were a container for a secret wish buried under layers of concealment." Thus, a person who is concerned with impotence is not more likely to dream about broken candles, but may well dream about impotence.