Facebook’s Massive-Scale Emotional Contagion Experiment

Facebook researchers have published a paper documenting a huge social experiment carried out on 689,003 users without their knowledge. The experiment was to prove that emotional states can be transferred to others via emotional contagion. They proved this by manipulating different user’s newsfeed to be more positive or more negative and then measuring the emotional state of the user afterwards by analysing their subsequent status updates.

we test whether emotional contagion occurs outside of in-person interaction between individuals by reducing the amount of emotional content in the News Feed. When positive expressions were reduced, people produced fewer positive posts and more negative posts; when negative expressions were reduced, the opposite pattern occurred.

They demonstrate how influential the newsfeed algorithm can be in manipulating a person’s mood, and even test tweaking the algorithm to deliver more emotional content with hope that it would be more engaging.


Ref: Facebook’s massive-scale emotional contagion experiment – Algopop