A U.S. research team has come up with a remote-sensing mechanism to record how millions of people around the world were feeling on any particular day, without their knowing.
Peter Dodds and Chris Danforth, a mathematician and computer scientist working in the Advanced Computing Center at the University of Vermont, say that their methods show that Election Day, November 4, 2008, was the happiest day in four years.
Revealing their results in the Journal of Happiness Studies, the researchers have also said that the day of King of Pop Michael Jackson's death was one of the unhappiest days.
"The proliferation of personal online writing such as blogs gives us the opportunity to measure emotional levels in real time," they write in their study.
The researchers have revealed that their mechanism begins with a website, www.wefeelfine.org4, which mines through some 2.3 million blogs, looking for sentences beginning with "I feel" or "I am feeling".
"We gathered nearly 10 million sentences from their site," Dodds says.
The researchers then drew on a standardized "psychological valence" of words established by the Affective Norms for English Words (ANEW) study, and gave each sentence a happiness score.
In the ANEW study, a large pool of participants graded their reaction to 1,034 words, forming a kind of "happy-unhappy" scale from 1 to 9. For example, "triumphant" averaged 8.87, "paradise" 8.72, "pancakes" 6.08, "vanity" 4.30, "hostage" 2.20, and "suicide" 1.25.
The sentence "I feel lazy" would receive a score of 4.38.
"Our method is only reasonable for large-scale texts, like what's available on the Web. Any one sentence might not show much. There's too much variability in individual expression," Dodds says.
However, that is the beauty of big data sets and statistics.
"It's like measuring the temperature. You don't care where the atoms are. You want to know the temperature of this room or this town. It's a coarser scale. We're interested in the collective story," Dodds says.
Given that many blogs are connected to demographic data, the researchers believe that their approach can let them measure the rise and fall of happiness of, say, people under 35 in California on Wednesdays, and compare to other places, age groups, and days.
"We were able to make observations of people in a fairly natural environment at several orders of magnitude higher than previous happiness studies. They think they are communicating with friends," Danforth says.
However, since blogs are public, he says, "we're just looking over their shoulders."
Though their method is generally focused on how writings are received rather than what an author may have intended to convey, it does allow them to estimate the emotional state of the blog authors.
"We are thus able to present results of what might be considered a very basic remote-sensing hedonometer," they write.
The researchers have also revealed that their findings run contrary to recent social science data that suggest that people basically feel the same at all ages of life.
They say that their method shows a more commonsensical result: young teenagers are unhappiest with a disproportionate use of "sick," "hate," "stupid," "sad," "depressed," "bored," "lonely," "mad," and, not surprisingly, "fat." Then people get happier until they are old, when happiness drops off.