Researchers said Shaquille O'Neal was the happiest tweeter
Researchers at the University of Edinburgh have been analysing celebrity Twitter messages in a bid to find out how happy the senders are.
They believe the study could provide insights into the emotional well-being of the general population.
The researchers looked at word patterns in the tweets of 13 celebrities.
Basketball player Shaquille O'Neale was said to be the happiest tweeter, followed by cyclist Lance Armstrong and television presenter Jonathan Ross.
The rapper Snoop Doggy Dogg was the least happy.
The study, which was carried out in partnership with a technology firm, found that the majority of celebrity messages were happy and positive.
They used computer analysis of messages posted on the Twitter social networking site to pinpoint the underlying emotions and determine the relative happiness of the celebrities writing them.
Ed Cochrane, from the University of Edinburgh Business School, said there was a "serious point to this research".
The researchers plan to use the technology to analyse links between emotion and important lifestyle issues.
For example, they hope to identify whether widespread social problems - such as obesity and alcoholism - have common emotional links that could be detected through the monitoring of online communications.
Mr Cochrane said: "We hope this type of analysis will shed light on the emotions involved in real social situations, helping to shape policy for the better."
The researchers will monitor the emotional content of social networking sites of participating residents from major cities.
One of the things they hope to look at is whether there are common emotional factors that determine why Glaswegians die younger, on average, than people from the rest of the UK.