There are several scientifically grounded theories about how dreams arise and what they do in the human brain. One of the most renowned dream researchers is Antonio Zadra, Professor of Psychology at the University of Montreal. Together with psychiatrist Robert Stickgold of Harvard Medical School, he has published a new, widely discussed book about the mystery of sleep, as reported by the magazine Der Spiegel.

Nighttime networking

For their book, Zadra and Stickgold studied nightmares, examined sleepwalkers, collected 15,000 dream reports, and conducted experiments in sleep laboratories. Their new theory of dreaming suggests that dreams correspond to a kind of nighttime restructuring of the brain. What we experience, learn, and perceive during the day is linked at night with existing memories. This happens in a highly creative way, in which impressions and thoughts are connected in new contexts through dreaming.

A large brainstorming session

At night, the brain is cut off from the outside world. It then begins to sort all the impressions stored in memory throughout the day. During dreams, the brain explores, tests, and even experiments with seemingly unusual possibilities. It is like a vast brainstorming process that triggers wild fantasies and apparently unrelated images. Such theories are almost impossible to prove scientifically. Dreaming subjects cannot be directly questioned. Researchers therefore rely, among other things, on reports written by participants the following day. 

The dream of a dream recorder

The dream researchers Zadra and Stickgold themselves dream of a dream recorder that would allow nighttime brain journeys to be recorded from the outside. However, they are not very convinced of the idea. In their book, they raise doubts about whether such a device would even be desirable—and whether dreaming might be better left as a final realm of mystery.