First-Night Effect: A Well-Known Nuisance for Humans Abroad

Holidays! Time to get away from school or work and leave the daily grind behind oneself when you part on a holiday trip. Sounds great, right?

Sure it doesâ€"but there is a catch for many people, including me. I seem to sleep less well when I’m not in my bed. For a couple of months now I've tracked my sleep using an app on my smartphone. It gives me a scoring per night, but it also analyzes trends. So for instance, when I’m not at home (checked via GPS), I sleep less well, especially on the first few nights. I travel for family and work reasons, which didn’t make a difference;I lost about 10% of sleep quality overall.

That's nice, of course, but what does science say about it? Awhile ago, Medical News Today reported on a study where this First-Night Effect was analyzed. (It even has its own acronym: FNE!)For instance, I learned that sleep researchers discard the first night from studies of other sleep-related phenomena, because it isn’t representative for the patient. An odd phenomenon indeed, but why does it happen?

This new research was led by Yuka Sasaki at Brown University,and found the following results. A first result showed that people were more sensitive to sound, and therefore woke up more quickly during the night. That seems understandable, but the second result was more surprising: there is a left and right brain imbalance. The left brain was less asleep than the right one, and the more there was an imbalance, the less well a person slept that night.

Having such an imbalanced brain seems a disadvantage, but the study cites birds and dolphins, both of which are able to let only their left or right side sleep and keep the other one active to guard against predators and other dangers. It’s not exactly the same (and why only the left brain?), but a third experiment showed that subjects were able to signal better and more quickly when they heard a sound in their first night than on subsequent nights.

The reasoning here is that when we're in a new, unfamiliar environment, sleeping less would have an evolutionary benefit, namely being on one’s guard and anticipating possible predators. It still would be nice to be on one’s guard on subsequent nights, but maybe sleeping somewhere unusualcalls back this prehistoric mechanism back into life? In any case, really fascinating research. As the article concludes, it’s new research and only in its infancy, but I sure hope there is some follow-up on this.