Has science evolved to record dreams?

Brainwave recordings show very little difference between REM sleep and the awake state

Our understanding of human biology has taken large strides in the last century. However, progress in our understanding of dreams has been really slow. The biological function of dreams is a grey area; the only sure thing is that most human beings dream regularly.

The phase of sleep associated with vivid dreaming is called REM (rapid eye movement) sleep. People who have woken up in this phase of sleep often report that they were dreaming. The rapid eye movements are a puzzle to researchers because they are difficult to measure.

A recent report ( Science Vol. 377, 2022) addresses the question of whether eye movements are related to whatever is going on in the dream. Could the movements carry information about a dream that could be analysed and interpreted?

But first, some background on the interpretation of dreams. The early twentieth century was dominated by the theories of Sigmund Freud, focused on the symbolic meaning of images recollected from dreams. The discovery of REM sleep, in 1952, led to a shift away from psychoanalysis.

The brain was found to be as active in REM sleep as in the fully awake state. Yet the body was inactive, asleep. REM sleep was found in all mammals and birds. Michel Jouvet showed that inducing damage to the brain stem in a cat freed it from bodily immobility in the dream state. This cat would noisily fight with other cats, stopping when it woke up.

The recording of brainwaves (EEG) provided fresh insights. These recordings showed very little difference between REM sleep and the awake state. More surprisingly, the neuroscientist Matthew Wilson recorded brain activity in a rat while it was exploring a maze and, not much later, obtained identical brainwaves when the same rat was in REM sleep — was it solving the maze in the dream?

Another way of studying dreams was to compile vast databases of dreams. Analysing 50,000 dreams led the compiler, Calvin Hall, to conclude that most dreams did not resemble surrealist paintings, and were fairly predictable. Children may smile while dreaming, as children were more likely to dream of animals, but adult dreams were not very pleasant and were often filled with moments of anxiety.