Facebook exec: study communicated "terribly" [VIDEO], Facebook communicated "terribly" regarding a controversial study in which it covertly manipulated users' feelings, the social network's COO Sheryl Sandberg admitted Wednesday.

Facebook came under fire after the revelation that the social media giant manipulated users' News Feeds for an emotion study.

Facebook received backlash after participating in a study that saw the company clandestinely tweaking content seen by more than 700,000 users for a psychology experiment.

The research was an experiment as part of product testing, Sandberg told a women's business seminar in New Delhi when asked whether the study was ethical.

"This was communicated terribly and for that communication we have apologised," she said.

"We communicated really badly on this subject," she said, before adding: "We take privacy at Facebook really seriously."
 
Researchers did not tell users the News Feed manipulation would be taking place, however, the actions by Facebook is legal due to terms laid out in the user agreement when an individual signs up for the site.

The results indicate "emotions expressed by others on Facebook influence our own emotions, constituting experimental evidence for massive-scale contagion via social networks", researchers concluded, and noted emotion was relevant to human health.

The psychological experiment has ignited concerns of the mood-altering capacities of the site, which has 1.2 billion users.