For most of human history, dreaming has been seen as a second “reality” in which altered forms of perception provide insights into ourselves and others, our fears, fantasies and motivations or even the future.
What is dreaming? What does science say? And what mysteries remain?
In the developed world, the cultural importance of dreaming has diminished significantly over the last 100 years. In part, this reflects the increasing dominance of science in the way we understand human experience.
Ironically, the initial shift to a modernist interpretation of dreams started with Freud, their modern champion.
A spiritual vehicle
The dream was a vehicle on which they could access the animal “spirits” often associated with the totemic affiliations and custodianship required by tribe or family group.
In theist cultures, which believe in one or more gods, the dream was more likely to be viewed as a form of divination and a medium through which god(s) could, albeit symbolically, communicate their knowledge of culture, purpose or the future.
With the decline of psychoanalysis as a cultural trope, the dream was increasingly subject to the harsh light of science.
For the next 20 years there was an incredible flourishing of dreaming research.
Medical and psychological researchers were able to wake people while dreaming (or not) and ask them about the thoughts, feelings and ideas associated with the dream state.
Such studies confirmed many long-held beliefs about dreaming. Dreams were very similar to waking, at least in terms of the brain waves recorded on electroencephalogram (EEG) machines, which measure and record the electrical activity from different parts of the brain.
And yet dreaming consciousness was very different to waking. It was more visual; and ideation (the creation of ideas) was more bizarre and often illogically connected.
Dreaming consciousness often mixed mundane aspects of our previous waking life with strange and symbolic mental activity.
People woken from dreaming reported feelings and emotions that were quite different to those reported when in deep sleep.
People who were in deep sleep used fewer words, were less coherent in their speech patterns and were less “conscious” than those who were awakened from dreaming sleep.
From the late 70s until the early 2000s, dream research shrivelled to a small field populated by practitioners. It was regarded by many as a quaint anachronism marking the transition between psychoanalytic and neuroscientific conceptions of mind.
But in recent years the role of dreams in cognition has been reinvigorated by the discovery that the two basic modes of sleep - dream (REM) sleep and Slow Wave Sleep (SWS) – play quite different roles in how we recover from the trials and tribulations of wakefulness.
In simplistic terms, SWS regulates physical recovery and REM mental recovery.
Starting with rodent studies, depriving animals of REM sleep was associated with impaired learning. The way in which memories are laid down and learning consolidated is profoundly linked to brain activity during dreaming sleep.
More recently, the same phenomena have been observed in human studies – and these have spawned a whole new field of REM sleep research linking the quality and quantity of dream sleep to memory and learning.
Back to the start
Ironically, the story may yet come full circle. While the first generation of “scientific” dream research did not find a simple link between the reported content of the dream and psychological health, the next generation of dream research may well uncover a link, however subtle.
Many of the drugs we use to treat depression have profound effects on REM or dreaming sleep. We know the ways in which depressed patients learn and recall memories is very different to people who are not depressed.
Depressed people are more likely to recall negative events, experiences and emotions, and more likely to forget positive ones. We know that people who do not get enough sleep, especially REM sleep, do not learn as effectively.
The next 20 years promise a very new and exciting period for research into REM sleep.
But if we stand aside from the immediacy of the new technologies of sleep and the “science” of recent dream research we can see some broader patterns repeating in the human history of dreaming.
We are still looking at dreams as a different state of consciousness that merges aspects of sleep and wakefulness. We still see dreams as an aspect of mind and brain that can influence how we see and interpret the world.
We now have sufficient knowledge of genetics to see that our brains carry the seeds of the past and that the ways our brains operate do reflect the collective unconscious – an idea posited by Freud’s famous student, Carl Jung.
We still see dreams as a source of inspiration and a canvas upon which we can create new and different possibilities, new futures.
One can only wonder on how we might understand and use our dreams in another thousand years.
See more Explainer articles on The Conversation.