Your Brain Still Makes Decisions While You Sleep

Ever been told to ‘sleep on it’? Well, that isn’t bad advice, because even though your mind won’t begin new tasks while you’re asleep, it will continue working on open problems.

In a study published in Current Biology, researchers found that sleeping brains will continue responding to external stimuli and continue making decisions.

Researchers conducted two experiments. In both, subjects were told words, which they then had to sort into categories. In the first experiment, the categories were animals and objects—for example, ‘cat’ and ‘hat’. In the second, the categories were real words and fake words—for example, ‘truck’ and ‘ubuto’. Subjects sorted words by pressing corresponding buttons, and, importantly, buttons were placed at their left and right.

In both experiments, subjects had EEG electrodes placed on their heads so that researchers could monitor brain activity. Both experiments also took place in with subjects lying down in dark rooms, so that they could fall asleep—but new words kept coming. As you’d expect, subjects stopped pressing buttons once they fell asleep, but, thanks to the EEG electrodes, researchers could see that their subject’s brains continued to respond to the words. The motor area of brain’s right hemisphere lights up when it wants to press a button on the left, and the opposite is true of a button on the right, so researchers could see whether their subjects wanted to press the correct buttons.

Interestingly, once the subjects woke up, they remembered the words they heard while awake very well, but didn’t remember any of the words they heard while asleep, meaning that they processed those words subconsciously.

Hopefully, in the future, research like this will lead to a future where you can learn stuff while sleeping, like Homer Simpson in our favourite subplot ever. In the mean time, don’t be afraid to take your problems to bed—you might wake up with a solution.

Photo courtesy of Jill Justus.

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