Facebook is the king of the social media sites, and it was apparently also trying to become the king of the Internet social experiments when it carried out an emotion study of its users. Unfortunately, the way the social media site carried out the emotion study has come under fire from many scientists in the field, citing among other things a lack of “informed consent.”

Facebook manipulated the newsfeeds of more than 700,000 users as a way to see if it would affect user emotions. The scientists who have weighed in on Facebook’s little study say the way they carried it out broke quite a few ethics rules. James Grimmelmann, a professor of law at the University of Maryland, posted a recent blog post that Facebook didn’t allow users to decide whether they would actually take part in the study.

Image via Shutterstock

Grimmelmann added the study actually harmed users by changing their mood. The scientists added that this particular move was even bad for Facebook. One of the social media sites’ researchers, Adam Kramer posted a rather lengthy defense of why the site did what it did. Kramer says the site carried out the study the way it did, "because we care about the emotional impact of Facebook and the people that use our product." He said that he and his colleagues "felt that it was important to investigate the common worry that seeing friends post positive content leads to people feeling negative or left out."

The experiment worked by hiding a small percentage of emotional words from people’s news feeds to see what the reactions to the posts would be and how many likes they would get from other users. This is hardly the first time that Facebook has messed with its users’ settings, but it is the first time the social media site has gone out of its way to trick its users—It is the manner in which the site did it that has researchers up in arms.