Sunset

Maybe you’re bright and full of optimism when the sun has just come up, but you’re falling apart by the time you get home in the evening. Or maybe you can barely crawl out of bed in the morning, but you start to perk up as the sun is going down.

Whatever your individual time-of-day preferences, you’re probably aware that your brain isn’t the same at all times. Our alertness naturally fluctuates over the course of a day.

Psychologists know this too, which is why many studies have tackled the question of how people’s behavior changes hour-to-hour. Here are some trends researchers have found.

More Cautious Decisions in the Morning

A recent study analyzed the logs of chess servers. The researchers thought about each chess game as a sort of experiment where each participant had to make 40 or so decisions about what moves to make in a finite window of time.

It turned out that people tended to be more cautious in the morning, opting for slower but more accurate decisions. At night, people made decisions more quickly but with less accuracy.

So which one was better? Neither, in fact. The two styles had different advantages and disadvantages that tended to balance each other out.

The Best Time of Day for Math?

In 2008, researchers from University of Bologna had a group of college and graduate students complete arithmetic tasks at 9 AM and 1 PM, looking to see whether there were differences in how people performed on the task at different times of day.

Overall, the participants ended up doing better in the afternoon than in the morning.

The researchers found that part of the difference in performance came down to alertness. Perhaps not shockingly, people tended to be less alert right after they’d rolled out of bed.

That said, not all of the performance difference could be explained by alertness. The researchers suggested changes in working memory capacity as another possible cause although more research is needed to know for sure.

When Rewards Are More Rewarding

Here’s another point for Team Afternoon. Research done in 2014 revealed that the striatum, a region of the brain involved in processing rewards, seems to be more responsive to monetary rewards in the afternoon than in the morning.

The authors pointed out that this is in line with a more general idea that afternoon is the time when people are in their best moods on average. In other words, of course rewards are more rewarding in the afternoon because everything’s better in the afternoon! Or so the theory goes.

It’s worth keeping in mind that these results are all trends for groups of people. Not everyone is going to be better at arithmetic at 1 PM or more reckless in the evening!

Maybe the takeaway is that it’s best to find what our personal peak times of day are. We all have brains that work differently at different times of day, but our brains don’t all work differently in the same way! So find what works best for your circadian rhythm, and go with it.

Image: Flickr/Vince