This is an archived article that was published on sltrib.com in 2011, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.
Our overall happiness is apparently in decline.
How do we know? It's on Twitter.
A team of mathematicians from the University of Vermont analyzed 4.6 billion Twitter messages worldwide over 33 months. They assigned happiness grades to more than 10,000 of the most common words, crunched all the numbers and plotted them on a graph that shows a gradual downward slope during the past year and a half or so, through mid-September.
Their gloomy findings have just been published in PLoS ONE, an international, peer-reviewed online journal that publishes papers from various fields in science and medicine.
Not all the news is bad. The researchers say their measure of collective happiness tends to spike on Christmas — and on many other holidays, too, for that matter. Moreover, happiness tends to peak on weekends, and plummet, at least relatively, on Mondays and Tuesdays.
The study's data include 46 billion words written by 63 million Twitter users between Sept. 9, 2008, and Sept. 18, 2011. Each of the most commonly used words was assigned a number on a happiness scale of 1 to 9 — 9 being the happy extreme. "Laughter," for example, registered 8.50; "the," 4.98; and "terrorist," 1.30.
Twitter is the social networking service that restricts messages to 140 characters or fewer. Those messages can be seen as a reflection of an individual's mood of the moment — as opposed to "a longer-term reflective evaluation" of the person's life. Twitter users tend to be on the young side, but all age groups are represented in the sample, said Peter Dodds, an applied mathematician and the study's lead author.
"Twitter is a signal, just like looking at the words in The New York Times or Google Books. They're all a sample," Dodds said in a statement announcing the findings,
In a previous study, aided by aggregative websites and computer technology, Dodds and his UVM colleague and co-author Chris Danforth, a computer scientist, did a happiness analysis of 10 million blog sentences that began "I feel" or "I am feeling." They found, among other things, that overall happiness dropped on Sept. 11 anniversaries and on June 25, 2009, the day Michael Jackson died.
The Twitter study produced similar results from a much larger sample. Jackson's death produced the single-biggest drop in a single day. Other low points were registered on Sept. 29, 2008, when the U.S. government pledged to buy up banks' toxic assets; and various natural disasters in 2010 (Chilean earthquake in February, U.S. storms in October) and 2011 (earthquake and tsunami in Japan).
Seasonal cheer is apparently robust, however. Certain dates, on which happiness sharply deviates from nearby dates, are termed "outliers" — and Christmas is one of them.
"For the outlying happy dates, 2008, 2009 and 2010, Christmas Day returned the highest levels of happiness, followed by Christmas Eve," the article states. —
The numbers
4.6 billion
The number of Twitter messages analyzed
63 million
The number of Twitter users who tweeted those 4.6 billion messages
10,000
The number of words that were assigned happiness grades