I have to admit, I have been grossly underestimating Twitter. After all, who is interested in Sara Palin’s latest shopping trip, or in my announcement that I am going to take a… shower (to be polite about it)? And do I really have to get a blow by blow description of Amanda Knox’s court proceedings? I can wait 10 minutes and read it on the news flash. Ah, but here is what I was missing: I could not only get the facts about Amanda’s not guilty verdict- I could also get the feelings and attitudes of the people who followed the case. Or put in a wider context, I could witness the zeitgeist of the country, as it is being created. I could actually sense the mood of the country, even the whole world, and in real time. But for that I’d have to spend all my waking hours reading random tweets, seven days a week, 365 days a year, and end up brain dead. And what would I get for my troubles? Nothing; just a bunch of anecdotes. Alternatively, I could tap into a huge data base, like one maintained by Twitter, and employ some clever statistical methods of a branch of communications science called informatics. Sounds good, but I wouldn’t know how to begin –but other people do. And they did.

The 5-year-old social media Web site now claims that more than 100 million users post 230 million “tweets” (text messages up to 140 characters long) every day. In that torrent of data, some social scientists see an unprecedented opportunity to study human communication and social networks. In the 30 September issue of Science Cornell University Michael Macy and his graduate student Scott Golder report their effort to use Twitter to study the collective moods of millions of people in diverse cultures around the world in real time. Using a protocol provided by Twitter they downloaded more than 500 million tweets originating from 84 countries between February 2008 and January 2010. That’s how you get a representative sample! They searched these messages for roughly 1000 words on a list of words associated with positive (agree, fantastic, super) and negative (afraid, mad, panic) emotion. From this avalanche of data they could mine some fascinating observations.

On the micro level their findings paint a portrait of humanity’s daily and seasonal mood swings. Positive emotion runs high in the morning, throughout the day, and rebounds in the evening. The same pattern occurs on the weekends, suggesting it’s not just work bringing people down. People are happier overall on weekends, but the morning peak is delayed by a couple of hours, suggesting they sleep in. Across the seasons, positive emotion increased from late December to late June in the northern hemisphere (and from July to late December in the southern hemisphere) as the days got longer and decreased during the other half of the year, lending support to other research suggesting that it’s the change in day length rather than the absolute day length that determines seasonal mood swings. So just like the birds and the bees and the plants, we are controlled by light and by our biological clock.

Now look at the graph again. Do you notice the relentless downward bias to the mood slope? This is a macro level observation (not made by the authors). It looks like a long-term, secular trend of increasing world-wide pessimism. Surprise? All you need in order to understand this observation is to read your newspaper or watch the daily news. People are rising up in the Arab countries, in Israel, and in Europe. Even in the U.S. we are getting spontaneous protest movements against the status quo. The common denominator is dissatisfaction with the social order, and specifically –against an accelerating trend of inequality in income and opportunity.

The bigger lesson of this paper is that in this new world of massive-scale instant communication hitherto unimagined events are rapidly taking shape. From fueling political earthquakes to conducting social research that can determine public policy, the possibilities are dizzying.

Dov Michaeli, MD, PhD
Dov Michaeli, MD, PhD loves to write about the brain and human behavior as well as translate complicated basic science concepts into entertainment for the rest of us. He was a professor at the University of California San Francisco before leaving to enter the world of biotech. He served as the Chief Medical Officer of biotech companies, including Aphton Corporation. He also founded and served as the CEO of Madah Medica, an early stage biotech company developing products to improve post-surgical pain control. He is now retired and enjoys working out, following the stock market, travelling the world, and, of course, writing for TDWI.