Jesse Bering

Friday, June 19, 2:12 a.m.: Loading up the trunk of my car with clothes hangers when approached by two transients… try to engage them in good-natured conversation about the benefits of wooden clothes hangers over metal ones, but they make me uneasy, say they want to go out to get a drink but I’ve got to go. In a city somewhere… looks like a post-apocalyptic Saint Louis.

Saturday, June 20, 4:47 a.m.: Was just now trying to return my dead grandmother’s cane to her. Took elevator to her apartment… meant to go to the 8th floor, but elevator lurched up to the 18th floor, swung around violently then shot back down. Could hear voices in the corridors outside elevator shaft…. a mother yelling at her child. Grandma then became my other grandma, also deceased, yet in a nursing home; doctors say she’s doing fine.

Sunday, June 21, 5:02 a.m.: On a floating barge in the sea trying to get to some other country, just made it, the dogs are running all over the place but seem more like rodents.

Monday, June 22, 3.31 a.m.: Just learned that one of my colleagues died suddenly, everyone’s in shock (they say it was “an accidental overdose of oxygen from a breathing tank; he fell asleep”). Can’t believe it, was just talking to him today about death. Also something about an airplane delay… need to get home but can’t find my test results to submit, searching all over, trash cans, pulling out drawers… people preoccupied.  

These are dreams, of course. Mine from the past few days, to be precise—and they are totally absurd. Why on earth do our minds conjure up such ridiculous imagery, such inane thoughts, such spectacularly vivid and surreal landscapes, intense emotions—such narrative trash?

Over the years, many psychologists have conjured up their own evolutionary explanations. And it’s a fair assessment of the literature to say that we still don’t know why we dream. After all, although it’s relatively easy to see why sleep itself would have conferred evolutionary advantages (avoiding nocturnal predators, recharging our neural batteries and so on), it’s not entirely clear why we don’t simply sleep without dreaming.

Harvard University psychologist Deirdre Barrett might have some answers for us. In a recent review of evolutionary theories concerning the possible adaptive function of dreaming, Barrett shrugs off the better-known psychoanalytic theories of dreams (for example, Freud’s “wish fulfillment” and Jungian archetypes) as being irreconcilable with a Darwinian framework and instead highlights the major contemporary, biologically informed theories. Remember, the key question for us to consider is why dreaming occurs at all, since it’s not immediately apparent why natural selection wouldn’t have simply engineered a dreamless, non-REM sleep.

So, without further ado, here’s a snapshot of the current evolutionary contenders in the field of dream studies:

Brain Conditioning
In the 1960s, sleep researchers began to notice that, in contrast to other stages of sleep, the brain was especially active during REM sleep. Several researchers, including the psychophysiologist Fred Snyder, argued that the adaptive purpose of dreaming may therefore be primarily to stimulate the brain or to keep it “in shape” during prolonged periods of inactivity. Later research offered support for this general idea. For example, specific categories of neurotransmitters were shown to be highly active during this period, while others seemingly “rested.” And specific anatomical regions of the brain, too, were especially busy during REM sleep (especially the amygdala), whereas others showed a pattern of reduced activity compared to waking (the prefrontal lobes, parietal cortex and posterior cingulate). Finally, thermoregulation is turned off during REM sleep.