Twitter: Mood Ring For The World?

If you start the day feeling positive but feel yourself growing increasingly glum as it slugs along, you're not alone. A new study using Twitter to track daily, global mood swings found that people tend to have two peaks, happiness-wise: early in the morning and then again around midnight.

Sociologists at Cornell University tracked more than half a billion tweets from more than 2 million Twitter users across the globe over two years. Relying on language-monitoring software, they found that people tend to be happiest relatively early in the morning, but that good mood deteriorates as the day continues. The world's tweeters are then most positive again sometime around midnight.

"Everybody we told about this has had the same reaction: 'That's obvious. People go to work, they get stressed -- of course their mood deteriorates,'" Michael Macy, Ph.D., a professor of sociology at Cornell and one of the study's authors, told HuffPost. "It turns out, that's not true."

The researchers found that the mood swing pattern remained largely the same on the weekends, when most people aren't heading into the office. This, they argue, emphasizes the important role of sleep and natural circadian rhythms on determining daily highs and lows -- not just work. As the Mayo Clinic explains, everyone has an internal clock that impacts body temperature, appetite, hormonal changes and sleep cycles.

Indeed, on weekends -- when more individuals are likely to awake according to their own internal clock and not just when their alarm clock fires off -- people were more positive overall and had what the researchers dub lower "negative affect," i.e. feelings of distress, fear, anger, guilt and disgust. The researchers also found that the observed morning happiness spike came about two hours later, presumably because people were sleeping in.

Macy said the findings suggest there are many factors, including biological circadian rhythms and work, that all interact to impact mood.

According to study co-author Scott Golder, Twitter provided them with a unique platform with which to look at these issues of mood swings across the globe.

"Previous studies done in lab or clinical settings have used small samples of people and they were typically very homogeneous," he said. "What was most surprising here was how consistent this pattern was across 84 countries."