You’re not a monster if you don’t want to stay over after doing it with a new person the first time, especially on a weeknight. Research has confirmed a long-known phenomenon in which people sleep like utter crap their first night in a new place.
It’s called the first-night effect and experts have known about it for decades. Recently, a team from Brown University tested it out by having 11 people stay in their sleep lab for a few nights. The plucky subjects slept inside a medical scanner made bearable with blankets and pillows.
The participants took longer to fall asleep and got less deep sleep on the first night than on the second. Brain scans found that a specific part of the left hemisphere was more active than the right during a phase of deep sleep called slow-wave; there was no difference in activity during other sleep phases. During the second night, there were no significant differences between the hemispheres.
They tested the idea by having more people sleep in a normal bed wearing headphones. When irregular beeps were played in their right ear, which is associated with the left hemisphere, they were more likely to wake up and and also wake up faster than when beeps were played in their left ear (right hemisphere). Beeps in either ear were less likely to wake people up on the second night.
The authors think that these reactions could mean that when we’re away from home part of our brain is on night watch for new sounds, smells, or dangers. It’s like when animals sleep with one eye open. Some sleep experts are skeptical of the findings, but for now, feel free to use them as an excuse to go home and sleep in your own bed.