Theory #1
The Evolutionary Theory: We Dream to Practice Responses to Threatening Situations
Ever notice that most dreams have a blood-surging urgency to them? In dreams, we often find ourselves naked in public, or being chased, or fighting an enemy, or sinking in quicksand. Antti Revonsuo, a Finnish cognitive scientist, has shown that our amygdala (the fight-or-flight piece of the brain) fires more than normal when we’re in REM sleep (the time in sleep when we dream). In REM sleep, the brain fires in similar ways as it does when it’s specifically threatened for survival. In addition to that, the part of the brain that practices motor activity (running, punching) fires increasingly during REM sleep, even though the limbs are still. In other words, Revonsuo and other evolutionary theorists argue that in dreams, we are actually rehearsing fight-and-flight responses, even though the legs and arms are not actually moving. They say that dreams are an evolutionary adaptation: We dream in order to rehearse behaviors of self-defense in the safety of nighttime isolation. In turn, get better at fight-or-flight in the real world.
Theory #2
Dreams Create Wisdom
If we remembered every image of our waking lives, it would clog our brains. So, dreams sort through memories, to determine which ones to retain and which to lose. Matt Wilson, at MIT’s Center for Learning and Memory, largely defends this view. He put rats in mazes during the day, and recorded what neurons fired in what patterns as the rats negotiated the maze. When he watched the rats enter REM sleep, he saw that the same neuron patterns fired that had fired at choice turning points in the maze. In other words, he saw that the rats were dreaming of important junctures in their day. He argues that sleep is the process through which we separate the memories worth encoding in long-term memory from those worth losing. Sleep turns a flood of daily information into what we call wisdom: the stuff that makes us smart for when we come across future decisions.
Theory #3
Dreaming is Like Defragmenting Your Hard Drive
Francis Crick (who co-discovered the structure of DNA) and Graeme Mitchison put forth a famously controversial theory about dreams in 1983 when they wrote that “we dream in order to forget.” They meant that the brain is like a machine that gets in the groove of connecting its data in certain ways (obsessing or defending or retaining), and that those thinking pathways might not be the most useful for us. But, when we sleep, the brain fires much more randomly. And it is this random scouring for new connections that allows us to loosen certain pathways and create new, potentially useful, ones. Dreaming is a shuffling of old connections that allows us to keep the important connections and erase the inefficient links. A good analogy here is the defragmentation of a computer’s hard drive: Dreams are a reordering of connections to streamline the system.
Theory #4
Dreams Are Like Psychotherapy
But what about the emotion in dreams? Aren’t dreams principally the place to confront difficult and surprising emotions, and sit with those emotions in a new way? Ernest Hartmann, a doctor at Tufts, focuses on the emotional learning that happens in dreams. He has developed the theory that dreaming puts our difficult emotions into pictures. In dreams, we deal with emotional content in a safe place, making connections that we would not make if left to our more critical or defensive brains. In this sense, dreaming is like therapy on the couch: We think through emotional stuff in a less rational and defensive frame of mind. Through that process, we come to accept truths we might otherwise repress. Dreams are our nightly psychotherapy.
Theory #5
The Absence of Theory
Of course, others argue that dreams have no meaning at all—that they are the random firings of a brain that doesn’t happen to be conscious at that time. The mind is still “functioning” insofar as it’s producing images, but there’s no conscious sense behind the film. Perhaps it’s only consciousness itself that wants to see some deep meaning in our brains at all times.
What do you think? We are all authors, in a way, every night. Is there a mind behind what’s written in your dreams? Why are your dreams of use?
Thursday 12 November 2009
Modern Theories on Why Dreams Exist ☀
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