Facebook is being investigated by the Information Commissioner's Office (ICO) in the UK after a study showed that a psychological experiment influenced what the users saw in their news feeds, raising fresh privacy concerns.
A company researcher apologised on Sunday for a test in January 2012 that altered the number of positive and negative comments that almost 700,000 users saw on their online feeds of articles and photos.
Disclosure of the experiment prompted some members to express outrage on Twitter about the research as a breach of privacy. The data regulator's probe of the social network was reported earlier by the Financial Times. A spokesman for the ICO said on Tuesday that the agency would be speaking with Facebook and working with the Irish Data Protection Commissioner to learn more about the circumstances.
The ICO is investigating whether the company broke the Euopean Union's data-protection laws.
The Irish Data Protection Commissioner's office had been in contact with Facebook on privacy issues, including consent in relation to the research, and was awaiting a full report from the company, said John O'Dwyer, a spokesman for the agency.
Facebook's compliance with European Union law is governed by Ireland, because its European headquarters are in Dublin.