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 of happiness during the past year and a half or so, through mid-September.
The results of the analysis were published in journal PLoS ONE. The authors however agree that collective happiness tends to spike on Christmas and on other holidays. 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.
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 non-annual event that was the most positive day was April 29, 2011, the day Prince William and Kate Middleton were married. Tweets on this day were full of positive words such as “wedding,” “beautiful” and “kiss.”
“Negative days typically arise from unexpected societal trauma due for example to a natural disaster or death of a celebrity,” wrote the study authors. The day the world learned of the death of Osama bin Laden ranked as the day of the lowest level of happiness, judging by the frequency of negative words like “dead,” “death” and “killed.” The Chilean earthquake in February 2010 also ranked low in happiness, as did the March 2011 earthquake and tsunami in Japan and the October 2010 slew of storms in the U.S. Declines in happiness were also evident after news of the U.S. economic bailout and the spread of the swine flu.
The researchers are quick to add that feelings change quickly and the nature of happiness is one of the most complex, profound issues of human experience. “There is an important psychological distinction between an individual’s current, experiential happiness and their longer term, reflective evaluation of their life,” they write in the study, “and in using Twitter, our approach is tuned to the former kind.” “By measuring happiness, we’re not saying that maximizing happiness is the goal of society,” Dodds concludes. “It might well be that we need to have some persistent degree of grumpiness for cultures to flourish.”