WHEN BRAINS DREAM

Two sleep and dream researchers illuminate their specialty.

Zadra and Stickgold hit the ground running by insisting that Freud did not have the last word on dreams—or even the first. Earlier 19th-century scientists produced theories that Freud adopted or ignored, but his immense influence, especially the belief that he had discovered the source and meaning of dreams, discouraged research until decades after his death. Matters have improved since then, as psychological studies as well as neuroscience, aided by high-tech brain scanners, reveal a great deal about brain function. All animals sleep, but until perhaps 50 years ago, experts had no explanation except that it relieved sleepiness, and the popular explanation—to tidy up and rejuvenate the body—never acquired traction. The authors emphasize its essential role in learning and memory. In studies where subjects memorized a topic, a night’s sleep improved their ability to recall—but didn’t improve accuracy, as they also recalled errors better. Turning to their favorite subject, the authors agree with the “widely held view that dreams reflect the dreamer’s current thoughts and concerns as well as recent salient experiences,” but they doubt that dreams carry important messages and require interpretation. They explain dreaming as a form of “sleep-dependent memory processing” that “extracts new knowledge” from recent experiences but rarely offers “concrete solutions” to problems. Most readers will understand the authors’ theories, but they will especially relish the final chapters, which explore nightmares, lucid dreaming, narcolepsy, creativity via dreams, and even how to link a dream to waking-life events. Readers convinced that dreams reveal deep insights and those who dismiss them as meaningless will both enjoy a painless education on dreams and memory. Few will object to the authors’ preferred theory because, as good scientists, they present their evidence without claiming that it’s overwhelming.

An excellent update on the science behind dreams.