Dreams are one form of fantasy activity that apparently is universal, spanning all cultures and age groups. Indeed, they fit the characteristics of an instinctive behavior. Because of this universality, there has been much concern with the dream process. But psychology's interest in dreams is best ascribed to the influence of Freud. As previously indicated, Freud believed that the dream is the "royal road" to the unconscious. Through dream analysis, he contended, we can learn about unconscious wishes and desires and the symbolic manifestations of needs.
According to Freud, the purpose of dreams is to preserve sleep. By serving as a goal substitute, the dream allows the release of some of the internal tension that is associated with unfulfilled desires. Without this release the dreamer would be awakened by excessive internal stimulation. A simple illustration can clarify this idea. Assume that you go to bed without dinner. After some period of time, hunger cramps are felt that might cause awakening. During sleep, however, you dream about the ingestion of food. The content of the dream might be disguised, with the food appearing in symbolic form. The wish-fulfilling dream produces a diminution in subjective hunger, thereby reducing the stomach cramps and preserving sleep.
As the reader might anticipate, it is extremely difficult to gather scientific evidence that dreams are wish fulfillments and that they preserve sleep by reducing internal stimulation. But recent advances in dream research have generated data that are pertinent to some of Freud's presumptions.
For many years, useful scientific research on dreaming was not conducted. One reason for this shortcoming was that only the dreamer had direct access to the dream. Therefore, it was not possible to assess the reliability of dream reports. There was a need to have a witness to the dream in addition to the dreamer.
An objective technique for the detection of dreams was discovered in the early 1950's. During sleep, rapid eye movements (REM) under the lid were discovered. Individuals awakened during these REM periods reported dreams with a high frequency, while persons awakened at other times did not report having dreams. Some mental and cognitive activities do occur during the nonREM periods, but reports of visual-like experiences occur only during REM sleep.
Subsequent research also revealed that during the course of sleep there are cyclical patterns of brain activity. This activity can be monitored with an electroencephalogram (EEG) or polygraph. Four different patterns of brain waves have been detected during sleep. "Stage I sleep," in which there is a lack of
spindle activity and no "Delta" or large waves, is highly associated with REM periods and dream reports. It is now quite clear that the REM observations and particular patterns of brain waves provide reliable outward criteria for identifying the internal dream process.
During the course of an eight-hour sleep period, the individual has about five dream episodes, or an average of about one dream every 90 minutes. In general, the longer one sleeps, the greater the total dream activity. The average dream lasts approximately fourteen minutes, with the length of the dream increasing as the night progresses. In addition, the time between dream episodes decreases as the waking state is approached.
Given an objective dream index, one would expect that the "royal road" to the unconscious would become a superhighway and that the speculations of Freud would be either confirmed or discarded. This has not been the case. However, inferential data have been gathered that do bear upon some of the issues raised by Freud.
First, it appears that all individuals dream. The universality of the dream was anticipated by Freud and apparently lends support to his conception. But the universality even exceeds the boundaries suggested by Freud. Many species in addition to humans exhibit dream-state sleep. If it is inferred from REM observations that lower organisms also dream, then it is difficult to contend that the function of dreams is to drain internal stimulation. It is generally assumed that infrahumans have few social inhibitions and that their basic sexual and aggressive needs are satisfied. It seems, therefore, that dreams do not preserve sleep, but rather the presence of sleep ensures dreams.
Another finding that may be considered evidence in support of the Freudian conception of dreams is that there appears to be a "need" to dream. If the sleeper is awakened every time a REM period is entered, then the REM periods are more frequent on subsequent evenings, and it takes more vigor to awaken the sleeper. The organism appears to be making up a REM deficit.