Facebook is being investigated to see if an experiment in which it manipulated users' news feeds to study the effect it had on moods breached data protection laws.
The Information Commissioner's Office (ICO), the UK’s data regulator, is probing the experiment but a spokesman said it was too early to tell what part of the law Facebook might have infringed, according to a report in the Financial Times.
The physiological study, carried out by the social network and two US universities, saw almost 700,000 unwitting users’ news feeds secretly altered in 2012 to study the impact of ''emotional contagion'' – a phenomenon whereby people are more likely to post negative messages to the site if their news feed contains more negative posts, and vice versa for positive posts.
"It's clear that people were upset by this study and we take responsibility for it,” a Facebook spokesman said in an email reply. “We want to do better in the future and are improving our process based on this feedback. The study was done with appropriate protections for people's information and we are happy to answer any questions regulators may have."
Representatives for ICO did not immediately respond to an email seeking comment. The regulator monitors how personal data is used and has the power to force organizations to change their policies and levy fines of up to £500,000.
The experiment was carried out in one week during January 2012 in collaboration with Cornell University and the University of California.
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, with some referring to it as ''creepy'', ''evil'', ''terrifying'' and ''super disturbing''.
The Financial Times added that the Data Protection Commissioner in Ireland will also be contacted as the technology giant's European headquarters are in Dublin.