“Our feelings are always in the past,” says John Sharp, a psychiatrist at Harvard Medical School. “This is something that’s really outlived its adaptive value.” As an adult I should have control over my current situation, but I don’t. Am I like those lab dogs, shocked into helplessness?
At first glance, sleep might seem like quintessential avoidance, like burying your head in the pillow is no better than burying your head in the sand.
But I don’t feel as though I am not helping myself. After all, going to sleep isn’t like turning the lights off; the truth is that there’s a lot still going on while your eyes are closed. While we might be able to temporarily stave the flow of conflict by falling asleep, we’re not really escaping anything. In fact, sleep in some ways forces us to not only relive the emotional experience but to process and concretize it—by going to sleep I may be making the fight with my wife more real.
If you’re like me, you probably imagine memories work pretty simply: you have an experience, it gets stored somewhere, and then you retrieve it when you need it. But that leaves out a key step, memory consolidation, and that’s where sleep comes into play.
Here’s how it really works, according to Dr. Edward Pace-Schott, professor at Harvard Medical School’s Division of Sleep Medicine: When an experience is initially encoded as a memory, it rests in the brain’s short term storage facilities, where it is fragile, easily forgotten if other experiences come along quickly. In order for the experience to last, it needs to go through a process of consolidation, where it becomes integrated into other memories that you have. That’s why when you think of, say the 1993 baseball game between the Yankees and Orioles, you also think of bright green grass, the smell of peanuts and beer, your dad, and Bobby Bonilla, and not thousands of random bits and pieces.
Of course, not every experience is worth remembering. Only the highly intense experiences—positive or negative—are prioritized for storage later on. “Emotions put a stamp on a memory to say ‘this is important,’” says Pace-Schott. It makes sense: the color of the grocery store clerk’s shirt is significantly less essential than, say, your mother’s birthday.
If we didn’t shelve our memories appropriately, everything would be a jumble, and without consolidation, we would forget it all. Life would have no meaning, and more importantly (at least from an evolutionary standpoint) we would never learn anything—we’d be helplessly amorphous, easy prey.
Here’s the conundrum, though: the same experiences that are stamped as emotionally important can overwhelm your brain’s short term storage facilities. Dr. Rebecca Spencer, a professor at the University of Massachusetts Department of Psychology, likens it to a desk where “whatever is stressing you out is this big pile of papers, but there are also other memories piling up on you.” With more and more papers landing in front of you all day, you’ll never effectively get to them all. And emotionally rich experiences are all high priority messages, screaming to be dealt with right away. So what happens next?
“You can be driven to sleep simply by having a lot of emotional memories to process,” says Spencer. It takes sleep to provide the space needed to sift through the days’ experiences, and make permanent those that matter.
Studies show that sleep enhances your memory of experiences, and the effect is multiplied for experiences with the stamp of emotion. In fact, the memory-consolidation process that occurs during sleep is so effective that some scientists, including Pace-Schott and Spencer, have suggested that it could be used to treat PTSD. Spencer posits that keeping someone from sleep following a traumatic event could be good in the long run. “If you force yourself to stay awake through a period of insomnia,” Spencer says, “the [traumatic] memory and emotional response will both decay.”
On the flip side, when it comes to the majority of the negative things we experience in life—the things that aren’t necessarily traumatizing like, say, a fight with your significant other—we want to go to sleep, because that protects the memory and emotional response.
And Pace-Schott points out that sleep disruption may prevent consolidation of potentially therapeutic memories, sometimes termed ‘fear extinction’ memories. These are memories that can dull the effect of a traumatic experience by creating more positive associations with specific triggers.] This means that improving sleep quality following traumatic events may be crucial to preventing PTSD.