Does the Night Really Bring Advice? Here's What Science Says

Everyone knows the popular saying, "sleep on it," which suggests waiting until the next day before making a decision. But does it actually work? A recent scientific study provides some answers.

How often do we hesitate before making a big choice or decision? We mull over the situation from every angle, ask for advice from friends or colleagues, and yet remain undecided. Most of the time, taking a step back to weigh the pros and cons seems like sound advice. We've all heard the expression, "The night brings advice."

This saying implies that giving yourself a night to sleep on an issue allows for the necessary distance to evaluate it clearly. By morning, we're supposed to know the right course of action. But is this wisdom grounded in fact?

According to a new study published in September 2024 by researchers at Duke University, sleep indeed helps us make more rational and informed decisions, preventing us from being swayed by misleading first impressions.

To explore this, researchers designed an experiment resembling a garage sale game. Participants sifted through virtual boxes containing various objects and estimated their value. Some boxes had valuable items placed on top, making them easy to spot right away, while others required more careful consideration.

After exploring several boxes, participants were asked to choose their favorite one, with a cash reward equal to the total value of its contents. The majority chose boxes based on their initial impressions, focusing on the topmost items rather than assessing the full contents. In contrast, after a night of sleep, participants made more rational decisions, evaluating all the items without being biased by their position.

Why Does Sleep Help?

"When forming an overall opinion about something, we are often unduly influenced by the first piece of information we encounter, even when new facts emerge," the researchers explained. This is a psychological phenomenon known as primacy bias. However, allowing time—especially sleep—helps mitigate this effect, leading to better decision-making.

Previous studies have also shown that people are more adept at solving problems after sleeping, even those they were initially stuck on. Sleep helps uncover underlying structures, make subtle connections, and improve overall understanding. Conversely, lack of sleep significantly hinders our ability to make informed decisions.

Something to think about the next time you consider pulling an all-nighter!