Facebook is being investigated to assess whether an experiment in which it manipulated users' news feeds to study the effect it had on moods might have broken data protection laws, it has been reported.
The site faced a fierce backlash after it emerged it has been playing mind games on about 700,000 users - with no need to get experiment participants to sign any consent forms as they’ve already agreed to the site’s data use policy.
The Information Commissioner's Office (ICO) is said to be looking into the experiment carried out by the social network and two US universities in which users had their news feeds secretly altered to study the impact of "emotional contagion".
A spokesman from the ICO said it was too early to tell what part of the law Facebook might have infringed, the Financial Times reported.
The paper added that the Data Protection Commissioner in Ireland will also be contacted as the technology giant's European headquarters are in Dublin.
The experiment was carried out in one week during January 2012 in collaboration with Cornell University and the University of California.
The aim of the government-sponsored study was to see whether positive or negative words in messages would lead to positive or negative content in status updates.
Many users reacted angrily following online reports of the findings, which were published in the June 17 edition of the prestigious Proceedings of the National Academy of Sciences.
The Huffington Post UK spoke to a researcher specialising in Internet infrastructure and public policy about the creepy new Facebook revelations.
Christian Sandvig, an Associate Professor of Communication Studies and Information at the University of Michigan, told HuffPost UK that what Facebook is doing is "not an ethical research design."
"There is a big difference between our expectations for academic social science and our expectations for Facebook. And that difference is reasonable," he said.
"We are right to expect that psychologists are not secretly experimenting on us via our Facebook feed, but I certainly expect Facebook to experiment on its users for its own gain."
The experiment was perfectly legal according to Facebook's rules, despite questions being asked about whether it was at all ethical to make hundreds of thousands of unknowing users happier or more depressed than usual.
“*Probably* nobody was driven to suicide,” tweeted Mr Sandvig, adding a “#jokingnotjoking” hashtag.
Facebook’s data use policy says users' information will be used “for internal operations, including troubleshooting, data analysis, testing, research and service improvement,” making all users potential experiment subjects.
Even Susan Fiske, the Princeton University psychology professor who edited the study, felt uneasy about it.
She told The Atlantic: "I was concerned until I queried the authors and they said their local institutional review board had approved it -- and apparently on the grounds that Facebook apparently manipulates people's News Feeds all the time."
One of the Facebook researchers who conducted the secret study has since apologised - but defended the experiment.
Adam Kramer, who led the study, said: "The reason we did this research is because we care about the emotional impact of Facebook and the people that use our product," he said.
"We felt that it was important to investigate the common worry that seeing friends post positive content leads to people feeling negative or left out. At the same time, we were concerned that exposure to friends' negativity might lead people to avoid visiting Facebook. We didn't clearly state our motivations in the paper."