What if selfies posted on Twitter can reveal our mood - whether people who live in "happier" cities tend to post more selfies and whether they smile more while taking self-portraits?
A team of researchers from University of California, San Diego and City University of New York have analysed one million photos tweeted over a period of one year to gauge various moods.
They are now in the process to measure the "moods" of cities. The idea is to correlate the Twitter data with other sources of happiness like Gallup Poll results.
The researchers would focus on images in tweets as they believe images may transcend the limitations of language, LiveScience reported.
The project is one of the six winners of the Twitter #DataGrants programme, which gives researchers access to Twitter datasets.
Images would give researchers more objective measures of happiness than words because words may be subject to interpretation to a greater extent than images, the report added.
Previous research based on the wording of tweets has measured happiness in different geographic locations.