HuffPost has published a story that claims:

A newly published paper reveals that scientists at Facebook conducted a massive psychological experiment on hundreds of thousands of users by tweaking their feeds and measuring how they felt afterward.

Is it true that Facebook permitted researchers to alter users' data feeds without the users' respective permissions?

  • The claim isn't altering of user data but showing different status updates in the newsfeed.
    – Christian
    Commented Jun 29, 2014 at 20:51
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    Who claims that data was "altered"? As far as I can tell the claim is that the way that data was selected for display was changed, but no post was altered.
    – user5582
    Commented Jun 30, 2014 at 0:35
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    @Articuno Yes, it sounds very different without that key word. Edited.
    – user20862
    Commented Jun 30, 2014 at 0:38
  • I would also change the wording of without the users' resepctive permissions, because they did give it in the blanket agreement they should've read (I suppose). Wouldn't something like "without their explicit / specific permission or knowledge" be better? Otherwise the answer is probably something in the lines of no they did not, because their license allows them to do this, even though the question is more if they actually did it ;)
    – Nanne
    Commented Jun 30, 2014 at 7:14
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    I would suggest something like without the users explicit knowledge, but I'm not sure what the best wording is :)
    – Nanne
    Commented Jun 30, 2014 at 7:22

1 Answer 1


The experiment is published in the article "Experimental evidence of massive-scale emotional contagion through social networks" in PNAS.

The authors state:

The experiment manipulated the extent to which people (N = 689,003) were exposed to emotional expressions in their News Feed.


Two parallel experiments were conducted for positive and negative emotion: One in which exposure to friends’ positive emotional content in their News Feed was reduced, and one in which exposure to negative emotional content in their News Feed was reduced. In these conditions, when a person loaded their News Feed, posts that contained emotional content of the relevant emotional valence, each emotional post had between a 10% and 90% chance (based on their User ID) of being omitted from their News Feed for that specific viewing.

This cleary shows that the authors claim that they manipulated the feeds of hundreds of thousands of users.

The authors explicitly thank the Facebook team in the acknowledgements, so we can safely assume that Facebook did help the researchers to manipulate the feeds:

We thank the Facebook News Feed team, especially Daniel Schafer, for encouragement and support; the Facebook Core Data Science team, especially Cameron Marlow, Moira Burke, and Eytan Bakshy; plus Michael Macy and Mathew Aldridge for their feedback.

About the issue of informed consent the authors write:

As such, it was consistent with Facebook’s Data Use Policy, to which all users agree prior to creating an account on Facebook, constituting informed consent for this research.

They claim that agreeing to the Facebook policy when signing up constitutes informed consent, they did not explicitly request permission nor inform the involved users afterwards. There is a blog post on Science Based Medicine from David Gorski exploring the ethical issues behind this and the question whether this actually constitutes informed consent.

  • 4
    The primary author works for the Facebook Core Data Science team; is that not enough of an admission?
    – Oddthinking
    Commented Jun 29, 2014 at 18:48
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    @Oddthinking I find that formulation in the paper to be highly problematic, a clause in the ToS can constitute consent, but declaring it "informed" is quite a stretch.
    – Mad Scientist
    Commented Jun 29, 2014 at 19:02
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    For instance, from FB Data Use Policy: we also put together data from the information we already have about you, your friends, and others, so we can offer and suggest a variety of services and features. For example, we may make friend suggestions, pick stories for your News Feed, or suggest people to tag in photos.
    – nico
    Commented Jun 29, 2014 at 20:09
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    @nico Let me reiterate "Informed consent" is a technical term that includes resonable assumptions about what how a person might interpret the actual wording of the agreement. So agreing that my data might be used to "pick stories for your News Feed" does not automatically imply informed consent for them making biased selections from my data.
    – Taemyr
    Commented Jun 30, 2014 at 8:46
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    @Nico We are not arguing wether legal consent have been given. We are arguing wether "informed consent" have been given. This is a piece of jargon meaning consent with a full understanding of future implication of this consent.
    – Taemyr
    Commented Jun 30, 2014 at 10:34

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