This article first appeared in Issue 16 of our free digital magazine CURIOUS. 

Dreaming is an almost ubiquitous human experience. When we drift off each night, imagery fills our sleeping minds – sometimes it’s vivid and realistic, other times nonsensical or nightmarish. Some dreams are consigned to memory, to be shared, laughed at, or perhaps even Googled, while others are quickly forgotten. Despite their universality, there are still many unanswered questions surrounding dreams. Maybe the most pressing of these, for anyone who’s had a particularly intriguing one, is: “What does it mean?”

These days, we know a fair bit about what is happening in our brains as we sleep – we even have some insight into what dreaming might look like in other species – but as for why we dream and what those dreams could mean, there remains a lot of mystery.

In light of this, we decided to dive into the science of decoding dreams and ask: Is there really any merit in it? 

If you’ve ever dreamt about snakes or your teeth falling out (as, apparently, lots of you have) and wondered what, if anything, it might be able to tell you about the inner workings of your brain, this one’s for you.

What are dreams?

“Dreams are sensory experiences we have while asleep,” David Billington, a psychotherapist and Director of the Dream Research Institute, told IFLScience. “They can range from feeling impressions or subtle colours to complex narratives to the consciously-willed lucid dream experiences, in which you are aware that you are dreaming even though you are physiologically asleep.”

Anything is possible in dreams, Joseph De Koninck, Emeritus Professor of Psychology at the University of Ottawa, who has been studying dreams for 50 years, added, which has led him to deem them “open season for the mind”.

We’re still learning what happens in our brains while we dream, but we do have some idea, Billington explained.

“We can see that there is almost as much activity in the brain during dreaming as during wakefulness, though of somewhat different types. The visual, memory, and motor areas of the brain are active (though sleep hormones block most people from acting out their dreams), but the logic areas of the cortex are less active, which might be one reason for the bizarreness of many dreams.” 

Dreaming can happen at any time while we’re snoozing, but our most vivid dreams happen in a stage of sleep known as rapid eye movement (REM), during which – surprise surprise – our eyes move about rapidly.

It’s thought we spend around two hours dreaming each night, although quite why we do is debated. 

“There is so far no scientific demonstration that [dreams] serve a biological function,” De Koninck told IFLScience.

It has been suggested that dreaming may help us to process emotions and memories, and aid us in solving problems in our waking lives. Other theories, posit that dreams may benefit our perception of reality, or, à la psychologist Sigmund Freud, that they serve to protect sleep from disruption or represent the fulfillment of unrealized wishes. Francis Crick, who dabbled in dream theory after his work identifying the structure of DNA, came up with an explanation deemed “reverse learning” in which “we dream in order to forget.”

Even with these numerous theories, some of which hold more water than others, the question of why we dream still doesn’t have a definite answer.

Do they really have meaning?

Our old friend Freud would say – perhaps unsurprisingly given that this is Freud – that they represent repressed, often sexual, desires.

If you thought the question of why we dream was convoluted, the question of what they may mean is even more so, complicated further by the fact that it largely depends on who you ask.

If you happened to have the ability to time travel and asked the ancient Greeks or Romans, they’d probably tell you that yes, dreams have meaning, and that they acted as omens or predictions of future events.

Our old friend Freud, as we touched on above, would say – perhaps unsurprisingly given that this is Freud – that they represent repressed, often sexual, desires.

Carl Jung, who founded the field of analytical psychology, meanwhile, might remark that “dreams are messages sent up from the unconscious” and as such can help us understand our inner psyche.

But what do modern psychologists and psychotherapists have to say on the subject? Do dreams really have meaning? 

“‘Meaning’ is a slippery term in the context of medicine,” Billington told us. There is no scientific consensus on what specific dreams mean, but that doesn’t mean they’re not useful.

“One can also say in a very broad sense that dreaming of specific things means that those things are related to your waking preoccupations – be that consciously, semi-consciously, or unconsciously,” Billington added.

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“But what a specific dream experience or image means to a specific person is highly subjective, just as what we make of waking experiences is highly subjective: a moment of conflict with a stranger might be highly disruptive for a librarian, but is just part of every day for a nightclub doorman.”

De Koninck agrees: “Dreaming of a train will not always mean death but will have different meaning depending [on] if you travel often by train, or if you are a train driver, or if you are afraid of taking trains, or if you have never been on one.” 

“In other words, the meaning depends on the waking experience of the dreamer [and] what the dream content resonates with you.”

Dreams can be a very useful source of self-knowledge, De Koninck believes, and can be used in various ways in psychotherapy.

“They have meaning in the sense that […] it's your brain, with your memory bank, and your emotions that are expressed, it's just that they're expressed in a different way.”

What can we learn from our dreams?

We might not be able to glean that dreaming about spiders universally means a fear of the unknown, as a quick Google might have you believe, but there’s still a lot that we, and particularly professional psychotherapists, could learn from them.

“Our dreams are part of our overall consciousness, but they happen in the absence of external stimulation, so they are in some ways a clearer picture of our ‘inner’ psychological selves,” Billington said.

As mentioned, dreams often reflect our waking lives, though they are not a replication of waking, just contiguous with it. They could therefore reveal things our minds have been ruminating on, with or without our knowledge. 

“[Dreams tend] to reflect your current concerns and amplify them. And that's where, in psychotherapy, it's interesting,” De Koninck said.

This is in keeping with the Continuity Theory of Dreaming, Billington explained. “Related theories are the Threat Simulation Theory and the Social Threat Simulation theory, which posit an evolutionary use for dreams: that they let us rehearse responses to threatening situations (be they physical or social) without actually putting ourselves at risk.”

In this sense, they could help us to adapt. “There could be a survival advantage to being able to ‘try out’ responses to situations before they happen,” Billington continued.

Dreams, or more specifically nightmares, can also be linked to trauma faced in our waking lives and “may be symptoms of broader disorders,” said Billington.

“Repeated dream recollections of frightening, damaging, or harmful memories, leading to disrupted sleep and physiological symptoms of stress (elevated heart rate, elevated levels of cortisol) are a sign of unresolved trauma.” Occasional or idiopathic nightmares can be normal, Billington added, but when “frequent and disruptive might be signs of other non-trauma psychological disruption, including Nightmare Disorder.”

Dreams are perhaps allegorical tales or myths about ourselves.

Persistent nightmares could be indicative of other conditions, such as PTSD or schizophrenia, according to De Koninck. They could also be a risk factor for suicide. “When someone has a lot of nightmares it has some meaning for us. Meaning towards saying: ‘Oh, you got to pay attention, there's something wrong there.’”

It’s also possible that suppressed thoughts and feelings, which we may not be aware of, could come back to us in our dreams. “It can therefore be useful to spend a little time reflecting on what comes up in our dreams,” Billington recommended, be that individually, with someone close to you, or, ideally, with a therapist.

“Is that dream of a colleague turning into a werewolf perhaps a dramatization of a side of them we are only peripherally aware of? Their volatile, changeable, aggressive side, perhaps? Or was it just that you watched An American Werewolf in London last weekend?”

It’s not just us who can learn from our dreams. When we share them with others we tell them things about ourselves that even we aren’t aware of, “because our vulnerability is shared via metaphor and symbol rather than directly,” Billington explained. “In this way, dreams are perhaps allegorical tales or myths about ourselves.”

All things considered, maybe we could all do to pay a little more mind to our nighttime imaginings, but best not to get too bogged down in unpicking them, particularly if you can’t remember them, De Koninck stressed.

“It can be important to pay attention to [dreams]. But if you don’t, no big deal. Sleep well – just get a good night's sleep.” 

CURIOUS magazine is a digital magazine from IFLScience featuring interviews, experts, deep dives, fun facts, news, book excerpts, and much more. Issue 19 is out now.