BOSTON (ASRN.ORG) - People are the happiest during Sunday mornings and saddest during Thursday evenings. 

At least, that's what Twitter tweets indicate. 

Researchers Alan Mislove and Sune Lehmann and their team from Northeastern University in Boston studied more than 300 million tweets from September 2006 to August 2009. The group wanted to find out whether they could measure the moods of millions of people using the social networking site. 

Researchers evaluated tweets using an Affective Norms for English Words (ANEW) word list that scores words based on their connotations. For example, "wedding" is a happy word, but "bored" is a sad word. 

Findings revealed a pattern each day — happy tweets from 6 to 7 a.m., sad tweets from noon to 4 p.m. and positive tweets again in the evening. 

Moods also change based on the day. More research is needed to figure out why, Lehmann says, but one guess is that people write "sad" tweets during the workweek. 

In miserable tweets, "if they're all saying 'my boss' or 'I have to go to work tomorrow,' then we can start to answer some of these questions," Lehmann says. 

Though the study found people are happier on certain days of the week, technology entrepreneur Jeff Pulver is skeptical. Events in someone's life affect emotions more than a specific day of the week, says Pulver, founder of #140conf, a series of conferences for the Twitter community.

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