Fascinating use of Tweets to understand human psychology:

Drawing on messages posted by more than two million people in 84 countries, researchers discovered that the emotional tone of people’s messages followed a similar pattern not only through the day but also through the week and the changing seasons. The new analysis suggests that our moods are driven in part by a shared underlying biological rhythm that transcends culture and environment.

The report, by sociologists at Cornell University and appearing in the journal Science, is the first cross-cultural study of daily mood rhythms in the average person using such text analysis. Previous studies have also mined the mountains of data pouring into social media sites, chat rooms, blogs and elsewhere on the Internet, but looked at collective moods over broader periods of time, in different time zones or during holidays.

“There’s just a torrent of new digital data coming into the field, and it’s transforming the social sciences, creating new lenses to look at all sorts of behaviors,” said Peter Sheridan Dodds, a researcher at the University of Vermont who was not involved in the new research. He called the new study “very exciting, because it complements previous findings” and expands on what is known about how mood fluctuates.

Unsurprinsigly, people hate mondays and love weekends:

To no one’s surprise, people’s overall moods were lowest at the beginning of the workweek, and rose later, peaking on the weekend. (The pattern of peak moods on days off held for countries where Saturday and Sunday are not the weekend.)

The pattern on weekend days was shifted about two hours later — the morning peak closer to 9 a.m. and the evening one past 9 p.m., most likely because people sleep in and stay up later — but the shape of the curve was the same.

“This is a significant finding because one explanation out there for the pattern was just that people hate going to work,” Mr. Golder said. “But if that were the case, the pattern should be different on the weekends, and it’s not. That suggests that something more fundamental is driving this — that it’s due to biological or circadian factors.”