When we sleep in a new place, our brains are actually in survival mode, only turning half off, with one hemisphere remaining more “Awake” than the other. Sleep scientists have regarded the First-Night-Effect in humans as a regular sleep disturbance for some time, but they’ve never fully grasped how it works. So sleep scientist Masako Tamaki and her colleagues took it upon themselves to find out why. Strangely, they found that the sleeping brains showed asymmetrical patterns of sleep activity, with one hemisphere humming along while the other slept. “We know that marine mammals and some birds show unihemispheric sleep, one awake and other asleep,” said co-author Yuka Sasaki, in a statement. Whales and dolphins drifting along in the ocean are highly vulnerable when sleeping so sleep with one half of the brain at a time to avoid getting caught unawares.
Armed with this knowledge, sleep scientists are hoping they can find a way to turn this mechanism off-mainly for people who travel often for work that may be perpetually sleeping in this state.