Facebook has gotten plenty of flack for its privacy practices, but here's a new way to distrust the social media service: It may be playing with your emotions.
As reported by The A.V. Club, in January 2012, Facebook adjusted its newsfeed algorithm for several hundred thousand users to see how what you see in your newsfeed affects your emotional state as part of a scientific study.
The resulting paper, published to The Proceedings of the National Academy of Sciences (PNAS), found that people mirror the positive or negative emotions that their friends express in Facebook posts--all without the aid of nonverbal cues like body language or tone of voice.
To pull this off, Facebook engineers tweaked what 600,000 users saw in their newsfeeds so that some saw more posts that expressed positive emotions, while others saw more posts that conveyed negative feelings. The result? People actually responded in kind: Those who saw more "positive" posts responded more positively, while those who saw more "negative" posts responded with negative feelings of their own.
It's a fascinating study, if more than a little creepy in terms of methodology. No word on how people responded to increased exposure to selfies.