Experimental evidence of massive-scale emotional contagion through social networks

Kramer, A. D. I., Guillory, J. E., & Hancock, J. T. (2014). Experimental evidence of massive-scale emotional contagion through social networks. Proceedings of the National Academy of Sciences, 111(24), 8788—8790

Summary

The authors of this article performed an experiment on over 689,000 Facebook users in which they biased their News feeds to either prefer positive or negative News. The study shows, that

1. user who have received the manipulated feed with less positive articles for one week tended to use fewer positive (-0.1%) and more negative (+0.04%) terms, compared to a control group.
2. Users which received more positive posts, in contrast, used more positive (+0.06%) and less negative (-0.07) emotional terms in their posts.

Although the measured effect is statistically small and it is not clear, whether only the way people expressed themselves, rather than their feelings, have been manipulated, this study raises many question in regard to the ethical issues regarding informed consent of users to participate in such experiments and/or to receive biased content at all.