Maybe we should ask the duck-billed platypus.
Back in the 1950s, scientists working on humans identified a state marked by increased brain activation, accelerated breathing and heart rate, and muscular paralysis. But perhaps the most remarkable feature was a flickering of the eyes beneath closed eyelids – because all these physiological changes took place while the subjects were fast asleep.
What the researchers had discovered became known as the “rapid eye movement” (REM) phase. Under normal circumstances, it recurs every 90 minutes or so, and takes up around 25% of our total time spent sleeping. It quickly became clear that people woken during REM had much better recall of their dreams; in fact, they would often say they’d just that moment been dreaming. As a result, the scientific community began to think of REM as the outward manifestation of the dream state. For the first time in human history, the most extraordinary and fantastical part of our lives had been subject to experimental observation.
Not only that, but animals were found to experience REM as well – some of them more often and for longer than humans. We now know that the REM-iest mammal of them all is, bizarrely enough, Ornithorhynchus anatinus, known to you and me as the duck-billed platypus. Perhaps we shouldn’t be surprised, since, as Nature notes, “an account from as long ago as 1860, before REM sleep was discovered, reported that young platypus showed ‘swimming’ movements of their forepaws while asleep”.
Authors might conjure up androids that dream of electric sheep, but can we now say for sure that platypuses dream of juicy crayfish? Not quite. Oneirology, despite all we now know about the physiology of sleep, remains a puzzling and controversial field. During non-REM sleep DNA is repaired and the organism replenishes itself for the day ahead. But the question of why we – and probably most other mammals – dream, one that troubled our ancestors, is still pretty hard to answer today.
Until relatively recently, it was taken as a given that dreams were meaningful. These strange visions that came during the night, when the darkness all around spelt danger, must be messages from the gods, or glimpses of the future. The dreams of powerful men or women could become famous; a class of people emerged whose job was to decipher them, since they might foretell the fate of the clan or nation. The Old Testament tells the story of Joseph, called on to interpret the pharaoh’s dreams of seven “fatfleshed” cows and seven “leanfleshed” ones. He trusted in God, who gave him to understand that this meant years of plenty for the kingdom, followed by a terrible famine.
Premonitions aren’t just the stuff of ancient history, however. Ten days before he was shot by John Wilkes Booth, Abraham Lincoln dreamt this:
I heard subdued sobs, as if a number of people were weeping. I thought I left my bed and wandered downstairs. There the silence was broken by the same pitiful sobbing, but the mourners were invisible. I went from room to room; no living person was in sight, but the same mournful sounds of distress met me as I passed along ... I kept on until I arrived at the East Room, which I entered. There I met with a sickening surprise. Before me was a catafalque, on which rested a corpse wrapped in funeral vestments. Around it were stationed soldiers who were acting as guards; and there was a throng of people, some gazing mournfully upon the corpse, whose face was covered, others weeping pitifully. ‘Who is dead in the White House?’ I demanded of one of the soldiers. ‘The President’ was his answer; ‘he was killed by an assassin!’ Then came a loud burst of grief from the crowd, which awoke me from my dream.
Coincidence, of course. Lincoln was at constant risk of attack, on the brink of victory after a bitterly fought civil war. But we can all recognise the uncanny quality of his dream: that chilling, portentous atmosphere. Where does it come from?
For the psychologist Linda Blair, there are two types of dream. The first represents a sorting-through of the contents of the day, a settling of sediment that is of no great consequence. But there are others, “those dreams that are accompanied by an emotional reaction, whether that’s happy, sad, or angry. They do have meaning.”
These, she believes, are attempts to deal with issues in our lives that we have been unable to resolve consciously. “They travel down into our unconscious mind to be worked on, where they don’t distract us and distress us so much.” Does she believe in premonition? “Dreams are predictive in my opinion,” she says, adding that “they don’t really predict the future, because no one can do that. But what they predict is what you’re going to be solving soon in terms of problems.” As a result, her patient’s dreams are valuable tools, allowing her to take a shortcut to the heart of a problem that’s clinically important but may not have been articulated in any other way.
Though Blair’s work draws on a range of sources, it has its roots in the revolution begun by Sigmund Freud at the turn of the 20th century. He was the first to attempt dream interpretation within a scientific framework, and saw dreams as the disguised expression of unconscious sexual and aggressive drives. But what he regarded as scientific many now see as mere conjecture.
“Freud was incredibly important in giving people another way of thinking about dreams,” says John Aggleton, professor of cognitive neuroscience at Cardiff University. “But the problem has been converting those ideas into something that’s truly testable. And that’s where, from a neuroscientist’s viewpoint, there’s always been a stumbling block.” But, he concedes, “there are a number of common themes in dreams. A lot of people dream about sex. The couple of recurring dreams that I have, and I’m sure other people have the same dreams, one of them is about losing my teeth, and another – and this is the classic one lecturers have – is just going to talk and finding out I’ve got no clothes on, no trousers and no underwear and there’s nothing I can do about it.”
Surely these kind of dreams demand a psychological explanation? “Yes, but they could also point to a really boring thing which is the fact that you dreamed you’ve lost your teeth because you’ve put your hand across your mouth and made it feel uncomfortable. Likewise, it wouldn’t be terribly surprising if feedback from how your clothes or lack of clothes feel might be guiding the way in which some of these dreams recur.”
What else have those sceptical of psychological theories of dreaming come up with? In the 1960s, scientists found that when an evolutionarily ancient structure called the pons was removed in cats, all REM sleep stopped. Some concluded that, during the REM phase, chemical messaging from the pons activated higher areas of the brain, prodding them to produce images and sensations, completely randomly. Dreams, then, were the higher brain making “the best of a bad job in producing even partially coherent dream imagery from the relatively noisy signals sent up from the brain stem”.
For some, this provided a new basis for understanding dreams: they’re the sparks and effusions of a system in standby mode – like the crackles of an old TV set cooling down. For Patrick McNamara, director of the evolutionary neurobehaviour laboratory at Boston University, it’s a myth that still needs busting. “One of the main things that gets on my nerves is [the idea] that dreams are just random flux during the night, that they mean nothing.” Instead, he says, “there’s pretty good evidence now that dreams are functional”.
Recent research has eroded the idea that dreaming only occurs during REM sleep, and that it’s a “bottom-up’ process”, with older parts of the brain activating the more recently evolved ones. But the paradigm initially shifted as a result of hundreds of studies of the content of individual dreams. These showed that people across cultures dreamed about similar things: for McNamara, evidence of an adaptive mechanism at work.
But why are they adaptive – beneficial to our survival as a species? Is it the old psychotherapeutic idea that dreams are the keys to unlocking problems involving relationships? “I think there’s good data that suggests that some of the things dreams do is help facilitate better social interactions,” McNamara says. But for him the real advantage is somewhat less poetic.
“Most scientists who study dreams think that we dream in order to practise avoiding threatening situations during the day … Men tend to dream about aggressive interactions with other men, whereas women tend to dream about verbal interactions with both men and women. And another pattern that was found repeatedly was that whenever male strangers appear in dreams, they tend to signal physical aggression.”
He goes on: “For men, the primary competitors for sexual access to females were other men, so they dream of aggressive interactions with other men. The appearance of male strangers signalling physical aggression probably relates to the fact that the most severe threats in ancestral times came from them. Raiders from a different tribe coming around and trying to steal women and resources: those were major survival threats.”
It’s interesting that, more than a century after Freud, whose focus on sex and aggression was ridiculed as an obsession by his detractors, they can once again be deemed the reason we dream. For therapists like Linda Blair, working in a broader framework – and for whom evidence is what helps a patient in distress – this can never be enough.
“I think there’s too much richness in each person’s brain to reduce things so specifically. For me dreams can mean anything. I don’t know until the patient and I work it out together.” Blair sees dream interpretation – which can itself produce subsequent clearer, or more baffling, dreams – as like “kneading dough”, working with an issue that might at first be too frightening or repulsive to apprehend, until it’s in a state that you’re ready to deal with. This can mean gradually coming to understand metaphors that are the subconscious’s way of bringing difficult issues to our attention. She cautions against jumping to conclusions over the meaning of fatfleshed cows and catafalques, however. “There are no universal dream symbols. Each person has their own symbol system, their own special private language and one of the real fun things to do in therapy is to decipher that.”
One thing we’ll never be able to access, of course, is the private language of the platypus. And the likelihood that animals dream – as Aggleton says, “anybody’s who’s got a pet dog or cat will be sure of that” – is a good reminder of the fundamental mysteriousness of all this. For humans, dreams are bestial, instinctive and intellectual all at once. They are distorted versions of our desires and the taut thrillers we write every night. Why do we dream? Because we are alive.
