Study: Americans moodiest on Thursdays

A group of researchers from Northeastern University and Harvard University have found a way to measure the mood of Americans throughout the week.

According to the website Mashable.com, researchers analyzed 300 million tweets measuring mood based on emotionally-charged words.

The study which is called "The Pulse of the Nation", found that people are happiest on Sundays and most depressed on Thursday evening. The results also found that the west coast is more cheerful than the east.

The researchers then created a mood map that shows Americans' emotional state throughout the day. Green means positive mood, red a negative one.