You lay down to go to bed, ready to fall asleep quickly and get a good night's rest. Just as you're about to fall asleep, some thought pops into your head, you can't stop thinking about it, and then before you know it the clock reads three in the morning. It's annoying, but Scientific American sheds a little light on why this happens.


We all have ideas that pop into our heads throughout the day, but when you're laying down to go to bed it's one of the few times when you're not distracted by anything else. Speaking with Scientific American, Barry Gordon, professor of neurology and cognitive science at John Hopkins University School of Medicine, explains what's going on:

We are aware of a tiny fraction of the thinking that goes on in our minds, and we can control only a tiny part of our conscious thoughts. The vast majority of our thinking efforts goes on subconsciously. Only one or two of these thoughts are likely to breach into consciousness at a time. Slips of the tongue and accidental actions offer glimpses of our unfiltered subconscious mental life... Although thoughts appear to "pop" into awareness before bedtime, their cognitive precursors have probably been simmering for a while. Once those preconscious thoughts gather sufficient strength, the full spotlight of consciousness beams down on them. The mind's freewheeling friskiness is only partly under our control, so shutting our mind off before we sleep is not possible.

Essentially, when your brain is finally given a moment of a rest, those subconscious thoughts can bubble up to the surface and keep you awake. Unfortunately, you can't simply switch your brain off just so you can get some sleep. To really avoid those restless nights the best thing you can do is get better sleep and train yourself to fall asleep quicker. If all else fails, a little math might at least direct that consciousness spotlight onto something more mundane.

Can we control our thoughts? Why do thoughts pop into my head as I'm trying to fall asleep? | Scientific American


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