For one week in 2012, Facebook conducted a psychological experiment conducted on 700,000 unsuspecting users. Facebook manipulated content users saw on their feed to spread negative or positive emotions. Here are five other experiments Facebook conducted that you may not have heard about.


For 500,000 users this year, Facebook snuck in fake captions from your friends quietly doubting the existence of god.


In May of 2008, 20,000 Facebook users had Shrek subtly Photoshopped into all of their photos.


For one week in January of 2014,Facebook sneakily replaced every photo, post and ad with images of Guy Fieri. Can you spot the difference?


70,000 Facebook users in 2012 received chats from friends that were horrifying lines from True Detective.


In February of 2011, 28,000 users had a bunch of dicks drawn on their profile photo. Just a bunch of dicks.