Media and the Mind: Emotional Contagion- The Facebook Experiments

Social media has tremendous power to share ideas, information and emotions to almost anyone or any audience you choose to reach. In the past it was the high level of communication and trade that, in part, drove our evolution into more complex social and technological communities, although at a much smaller scale than we are faced with today (See Our Time With TED). It seems then that many of our most recent and most widely exulted technologies strive for increased communication between people, from the invention of the telephone in 1876 to the development of a global internet (1989 – onwards), and GPS in the years 2000 – 2004 (seems longer right? Whatever did we do…).  This concept of sharing wisdom and evolution was first introduced to me during a talk by evolutionary sexologist Matt Ridley and extended to encompass the fact that at this stage the collective knowledge of humanity exists in no single mind, but depends on essential communication commodities like the internet in order to continue to innovate as a species.

Of course, this is exactly what is happening, you’re all here reading my lovely blog, and enjoying (hopefully) the fascinating topic of evolutionary sexology and how the internet will likely continue to accelerate our species evolution. Unfortunately this is not the whole picture. Aside from the ongoing net neutrality debate in the US a recent study published in Proceedings of the National Academy of Sciences (PNAS) observed that large scale emotional contagion was possible through the manipulation of social networks, or more specifically the prevailing emotion of Facebook users could be influenced by altering the prevailing emotion of their own newsfeeds.

While this all sounds fairly radical, the notion of emotional contagion has been studied since the 50s, although under different names. The idea states that emotional states are transmissible between in contact individuals both physically and verbally, but do so unconsciously, differing them from the other evolutionarily advantageous group emotions of sympathy and empathy. What makes the results of the PNAS study into Facebook newsfeeds so controversial is that it is the first “demonstration” of emotional contagion via a digital text platform, and one with over 1.4 billion users.

The process of emotional contagion has been proven experimentally through many different means, but their remains much confusion as to the mechanism of this mimetic behaviour or the reason for large scale emotional homogeneity observed in many studies. It was originally postulated that emotional contagion proceeds via mimicry of facial expressions and vocal tone upon exposure to donor emotional contacts, however the new study proves that non-physical exposure via Facebook is sufficient to induce similar emotions in recipient individuals. This not only turns previous (although fairly disorganised) studies on their heads, but also challenges the concept of our own emotions coming from within ourselves.


To achieve this result, researchers employed by Facebook reduced either the positive or negative content on 689,003 user’s newsfeeds without their knowledge, in order to observe the unbiased response to an increased negative or positive media environment. Given the volume of selfies, relationship debacles and holiday pictures posted to Facebook, the programme utilises a ranking algorithm to select content that is most relevant and engaging to you, under normal conditions. In the experiment, candidate positive and negative words (5.8 million words total) across 3 million statuses were omitted to see if it affected subsequent statuses. Remarkably if negative statuses were decreased the level of negative posts produced thereafter decreased and the number of positive statuses increased, the reverse was also seen when positivity was declined within the system. This clearly demonstrates that collective human emotion is transmissible (somehow) using modern media technology, but also the apparent frightening simplicity with which crucial human behaviour can be manipulated to generate a prevailing emotion between two simple states (happy or sad).

Human intelligence is increasing (somewhat dramatically) with an average of 3 IQ points per decade and while it is impossible to empirically link our globalisation to our intelligence it is not unreasonable to assume it plays a role, as it has done throughout our evolutionary history.  Therefore the idea of “collective human intelligence” will to some degree depend on the ability to communicate. Interestingly previous studies have proven the emergence of a “general intelligence” factor from human groups that was independent of the individual intelligence of group members but correlates with the social sensitivity of group members, conversational turn taking and… the number of female members per group, all of which improved group intelligence. Of course this work was on smaller groups and cannot encompass the 600,000+ Facebook guinea pigs, but if the social sensitivity of Facebook users can be so readily steered, it raises questions over both Facebook’s power and scientific practices.

“a matter of concern that the collection of the data by Facebook may have involved practices that were not fully consistent with the principles of obtaining informed consent and allowing participants to opt out”. Inder M. Verma Editor-in-Chief, PNAS

I expect any attempts to abuse this power in the future will be much less subtle than altering a single fleeting emotion, already a simple google of “emotional contagion” will find you a “sneaky new technique” for first date sex, so while it may seem like the next subliminal messaging, I wouldn’t worry and focus instead on jumping down Facebook’s throat for invading your privacy.

I leave you with a quote on the effects of negative emotional contagion that many of us have probably experienced:

“Before you diagnose yourself with depression or low self-esteem, first make sure your are not, in fact, surrounded by assholes” – Unknown



Kramer, A., Guillory, J., & Hancock, J. (2014). Experimental evidence of massive-scale emotional contagion through social networks Proceedings of the National Academy of Sciences, 111 (24), 8788-8790 DOI: 10.1073/pnas.1320040111

Woolley, A., Chabris, C., Pentland, A., Hashmi, N., & Malone, T. (2010). Evidence for a Collective Intelligence Factor in the Performance of Human Groups Science, 330 (6004), 686-688 DOI: 10.1126/science.1193147


photo credit: <a href=””>n0r</a&gt; via <a href=””>photopin</a&gt; <a href=””>cc</a&gt;


4 responses to “Media and the Mind: Emotional Contagion- The Facebook Experiments

  1. I first heard of the study on a blog about 5 weeks ago. My initial reaction was that the study gave very little information in proportion to degree of concern it raised about Facebook reliability. I am glad to see that someone has taken the information gained by the study and is willing to take it to the next step. The interpretation of the study’s findings coincides with other social situations from the past. One in particular is the radio broadcast of War of the Worlds in 1938 directed by Orson Welles. The manner in which the story was delivered was convincing enough to deceive a large number of listeners and manipulate their emotions. Even though the story was purely fiction, the fact that it was presented as a news report swayed the listeners’ reasoning to accept the fiction as reality. It is quite possible that the “general intelligence” factor of the radio listeners dropped by a small amount that day.

  2. Its shocking how few people knew about the study (although many of them may get their news from facebook itself). It was somewhat sensationalised in the media as I think facebook could provide an excellent platform for large scale sociological/psychological studies, as long as it is done ethically – and some-one keeps tabs on facebook since it has so much power!

  3. This article is very interesting. The participants were all uninformed of the “study” they were involved in. Something that is mentioned in both the article, and our coursework. Our book mentions very specifically not to take any over the phone surveys pertaining to a study, as credentials are hard to prove. Something that bothers me is that Cambridge University, an allegedly credible source, broke a cardinal rule of psychology by not gaining permission of the 600,000 + Facebook users used as Guinea Pigs. Another piece from my coursework was the comment about “getting a woman into bed on the first date”. We studied sex and learned that it is ingrained into everything we do. We think about it often, so it is no surprise any company would sell sex appeal or “secrets” to sex into the public in order to pursued us into clicking.

  4. Thanks Lucas,
    It was fairly essential that they were uninformed, so that the results were not biased by the subjects own perception of “happy” or “sad”, for the same reason they also used a computer to both select participants and candidate words to be removed.
    And yh Freudian psychology is used everywhere in the media, but I just meant it as a joke – sounds like a fairly ambitious piece of coursework to me….. 🙂

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