Evidence of massive-scale emotional contagion in social networks (2014)

An important point about this result: the significance is high because they had a huge population to test on, but the effect size is very small. The effect size is 0.001 which means that if one of your friends posts something negative (or positive), you have a 1/1000 chance of also posting something negative (or positive) as a result that you wouldn't otherwise have posted.

Anyone want to do a power calculation for an effect size of 0.001 and a sample size of 700,000?

Eyeballing it, I’m not convinced that’s enough.

This needs "(2014)" added to the title.

This appears to be a repost of the famous Facebook study that manipulated people's news feeds: https://www.theatlantic.com/technology/archive/2014/06/every...

I agree. Although perhaps more infamous than famous.

Thanks, I thought this was new, and was kind of amazed that they were doing this again.

OP here, and I agree. I will keep that in mind for next time. :)

I thought it was common sense

Evidence is better than common sense.