One part of our brain keeps a lookout when we sleep in a new environment. Duy Nguyen/Flickr April 21, 2016 How half our brain keeps watch when we sleep in unfamiliar places Masako Tamaki, Brown University and Yuka Sasaki, Brown University Have you ever arrived in a hotel room after a long flight and despite being exhausted, failed to fall asleep? This is called the first-night effect and we may have understood why it occurs.
