What goes on inside your brain when you’re dreaming? Well, as it happens, no one seems to know exactly. Not the mystics with the crystal balls, not the dream interpreters, and not even, as you might suspect, scientists. While several theories are floating about in both the scientific and nonscientific worlds about what dreams are, what causes them, and how the brain comes up with them, there’s no conclusive evidence about any of it.
The scientific theories come down to the following: Your dreams are expressing your repressed childhood longings; they’re sorting through the garbage of your day-to-day existence; or, finally — the one scientists are most recently exploring — they’re just random brain impulses and have very little significance whatsoever to your life choices as a whole.
Sigmund Freud was among the first to come up with dream theory, and, predictably, he suspected that dreams were based on desires that were either socially unacceptable or repressed for other reasons. For the most part, he believed that dreams were largely based in sexual desires and symbolism. Carl Jung, who studied under Freud, took the idea of psychological expression but went a bit further with it, disagreeing with Freud on the repressed nature of desires being expressed through dreams. He suggested instead the now popular view that dreams allow us to think through our problems and issues of the day, albeit subconsciously.
Then, in 1973, another theory started gaining ground. Harvard psychiatrists Drs. Allan Hobson and Robert McCarley carried out research that basically came down to this: Dreams are made of random electrical brain impulses. The brain is built up of billions of nerve cells, or neurons, and electrical impulses are sent from neuron to neuron, which enables “messages” to be transmitted in the brain. Every action we take — speaking, for instance — requires messages to go to and from the brain to the body, and these electrical impulses carry those messages through.
The Harvard psychiatrists believed that dreams were made of these random transmission impulses to and from the brain. Their theory, called the “activation-synthesis hypothesis,” was that the brain wants to make sense of what it has seen and experienced throughout the day, and so when you’re sleeping, it digs into that vat of information and starts the processing. According to Hobson and McCarley, the images are just leftovers of brain processing and our waking mind trying to process what it’s seen. They dismissed the idea that there are hidden meanings in dreams; Hobson called it “the mystique of fortune cookie dream interpretation.”
Their theories met with much opposition. Then, and even now, popular science has always had the opinion that our dream states and waking states were connected through our dreams, and this research went against the popular grain of thinking at the time.
This theory, however, is supported by other research. In a study of 1,000 people, researchers at Carnegie Mellon University and Harvard found that people attach more significance to dreams that feature familiar people or situations. More so, if the dream was about someone they liked, they attached more positive bias to it, and vice versa if it was about someone they disliked.
Other research suggests that very few dreams are actually about people or places the dreamer knows or has encountered. Most — that is, 80 percent — are actually random events or people the dreamer doesn’t know.
What Happens While You’re Dreaming?
So what goes on in the brain when you’re asleep? For that, you’d have to first understand the five stages of sleep:
- In the first stage, you’ve just closed your eyes and entered very light sleep that’s easy to wake up from.
- By the second stage you’re in much deeper sleep.
- By the third and fourth stage, you’re going to be very upset if woken up.
- The deeper we go into sleep, the slower our brain activity becomes; and by the fifth stage — which happens approximately 90 minutes after we’ve first dozed off — we begin rapid eye movement (REM) sleep, which is where dreams begin to take form.
- When we’re in the REM stage of sleep, the body is essentially paralyzed. Our heart rates go up, our blood pressure rises, and our brain activity is raised to the level it’s at when we’re awake. The body’s severed functions, scientists believe, are to make sure that you don’t actually act out your dreams as you’re having them. (Because otherwise you’d have some very upset bedmates.)
Very recently, however, after a 73-year-old stroke patient at the University Hospital of Zurich stopped dreaming, scientists reported that they may have located the part of the brain where dreams are created. The patient had lost several of her brain functions, including her vision, but while most functions returned after a few days of treatment, she was no longer able to dream. After monitoring the woman’s brainwaves for six weeks as she slept, scientists found that she slept fine and her REM sleep was perfectly normal, leading them to conclude that dreaming and REM sleep, while occurring simultaneously, are driven by separate brain systems.
Are Dreams Just Exercise for the Brain?
In a paper published in the journal Nature Reviews Neuroscience, Hobson wrote that the reason people forget so many dreams is because dreaming is nothing but a warm-up for the brain. It is exercising to remain fit so that it can be sharp during the day, he said, comparing it to jogging — where the body doesn’t remember every step, but it knows it has exercised. The research led to much controversy, arguments and further study in the scientific community. However, supporters say this could explain why 80 percent of dreams are often about people or places the dreamer has never come across, and research shows that most images that appear in dreams are often unique to that dream.
There’s still a long way to go before any of these theories can be proven beyond a reasonable doubt, but until they are, the speculation about how our brain functions and whether dreams hold any other significance remains to be seen. Until then, we’ll continue analyzing. Who knows — maybe sweet dreams may be the solution to our problems.