Covert Facebook Study
It looks like thousands of people may have taken part in an experiment by Facebook without realizing it. For one week in 2012, Facebook put upbeat posts on some of user feeds and negative posts on others. It was part of a psychological study Facebook did with researchers at Cornell University and UC San Francisco. The study showed that people who received bad news in their timeline tended to post more negative messages and just the opposite happened for those who received more upbeat messages in their timeline. There is no indication that anyone was asked if they wanted to participate in the study.