Most of us use Twitter to a) self-promote, b) find out what Kim Kardashian is up to, or c) freak out over the news. But for social scientists, a 24/7 global stream of constantly updated status messages is a rich vein for research — as Michael Macy and Scott Golder of Cornell University learned when they combed through more than 500 million tweets as part of a study that is being published in the Sept. 29 Science.
Macy and Golder searched those half a billion tweets — published by users from 84 countries between February 2008 and January 2010 — for roughly 1,000 words associated with both positive and negative emotions. The researchers also looked for emoticons.
What they discovered is that Twitter can serve as a kind of global mood ring, reflecting the rise and fall of emotions around the world. On Twitter, the researchers discovered, emotions tend to run positively in the morning, peaking around breakfast time before falling and bottoming out in the late afternoon, then rebounding again in the evening. That pattern held up across cultures and countries.
Interestingly, the same mood cycle recurs on the weekends, except pushed back a couple of hours since people tend to sleep and wake up later, which seems to indicate that it’s not simply the annoyance of being at work — and the pleasure of being off the clock — that drives those cycles, as Golder told the New York Times:
This is a significant finding because one explanation out there for the pattern was just that people hate going to work. 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.
Of course, work probably does play a role in driving our mood. Global emotions tended to hit an overall low on Monday afternoons before steadily rising and peaking on the weekends — although you could have learned that by listening to Rebecca Black. The study found that seasons did not seem to overly influence the mood — no evidence of any uptick of negative emotions during the winter months. Positive emotions did trend upward around the spring equinox and fell with the approach of the fall equinox in late September, suggesting that people were dismayed at the thought of the approaching shorter days.
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Admittedly, it’s not exactly earth-shattering that people around the world are just working for the weekend. But the sheer wealth of data produced by Twitter — and by other popular social media formats — allows researchers to examine the dynamics of large human groups in far more ambitious ways. Another group of sociologists at the University of Vermont mapped how the world via Twitter, responds to major news events, with negative emotions increased in the wake of the March earthquake and tsunami in Japan.
Of course, Twitter is an imperfect representation of how actual human beings actually feel. The software used by researchers struggles with sarcasm, which does sort of feature prominently in social media. (Maybe they can take a lesson from @Humblebrag.) And while preening social media dons may pretend otherwise, not everyone is connected, which means you’re getting a (relatively well to-do, young and tech-savvy) slice of the whole human pie. But every day that slice gets a little bigger, so expect more sociological social media research to come.
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Bryan Walsh is a senior writer at TIME. Find him on Twitter at @bryanrwalsh. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME