Retrospect and Prospects

This chapter uses the research findings presented in the earlier chapters to assess traditional theories of dreaming and dream content from the pre-neuroimaging era. It presents evidence that no past clinical theory, such as Freudian or Jungian theory, can explain any of the neuroimaging, developmental, or quantitative dream content findings presented in the book. Nor can a neurophysiological theory from the 1970s, which emphasizes the brainstem and rapid eye movement (REM) sleep as the key to dreaming, explain any of the many new findings. Just as important, the several adaptive theories of dreaming—which purport to explain the evolutionary value of dreaming—are refuted by the available evidence. This is especially the case for theories claiming that dreams are a form of rehearsal for improving social skills or for dealing with threatening situations, which does not fit with the relative lack of dreaming until ages 9–11 or with the findings on the nature of social interactions in dreams. Theories claiming that dreaming is based on the process of memory consolidation do not fit with the complete lack of evidence for memory consolidation during REM sleep, nor with the fact that there is a relatively small amount of memory consolidation in NREM sleep.