Aviva Rutkin, reporting in New Scientist:

A team of researchers, led by Adam Kramer at Facebook in Menlo Park, California, was curious to see if this phenomenon [of contagious emotion] would occur online. To find out, they manipulated which posts showed up on the news feeds of more than 600,000 Facebook users. For one week, some users saw fewer posts with negative emotional words than usual, while others saw fewer posts with positive ones.

Forget about the filter bubble, Facebook is (and has been since at least 2009) a Petri dish.

Click through to find out the results.

Related: Even the Editor of Facebook’s Mood Study Thought It Was Creepy