With the uproar continuing over Facebook's manipulation of some users' News Feeds to conduct an experiment on emotions, there are several things people need to understand.
News reports recently surfaced that Facebook made it possible for researchers to surreptitiously control the posts, comments and photos that about 700,000 users were seeing as part of a psychological experiment.
Users, analysts and bloggers have been voicing their outrage over what many are calling emotional manipulation and a breach of users' trust.
Here are seven things users need to know about the way the experiment was conducted, its legality, what Facebook had to say and what recourse users have.
1. What happened?
The Proceedings of the National Academy of Sciences (PNAS) published a study conducted by researchers from Facebook, the University of California and Cornell University on whether people's emotions can be influenced without face-to-face contact.
The study was conducted during the week of Jan. 11-18, 2012. It affected 689,003 English-speaking Facebook users.
In the experiment, Facebook temporarily influenced the kind of posts and photos users could see in their News Feeds, making it possible for researchers to show either mostly positive comments, posts and photos or mostly negative ones in order to see if the nature of the content influenced people's emotions.
As a consequence, users were not shown a regular cross-section of their friends' posts, but instead were given a manipulated feed.
Facebook noted that users could have seen their friends' content if they had gone directly to those Facebook pages, but much of that content was cut or emphasized on the News Feeds, which is where most users get their updates from Facebook friends.
2. What the experiment showed
The study found that people who saw more positive comments made more positive comments themselves, while those who saw more negative comments echoed the negativity of the posts they read.
The research is focused on what scientists call an "emotional contagion," or the ability to influence people to show the same emotions without direct personal contact or even their awareness.
3. Does Facebook normally manipulate your News Feed?
Yes, but it's not normally done to either cheer you up or depress you as part of a psychological study.
Facebook has been upfront in saying that it uses an algorithm that determines which stories appear first in users' News Feeds.
The social network has said it uses the algorithm to spare users from "spammy" content, duplicates and "like-baiting" -- attempts to boost circulation by trying to get users to like, comment on or share posts. Facebook contends that it's trying to provide the information users most want to see.
"Ideally, we want News Feed to show all the posts people want to see in the order they want to read them," the company wrote in a post. "This is no small technical feat: every time someone visits News Feed there are on average 1,500 potential stories from friends, people they follow and Pages for them to see, and most people don't have enough time to see them all."
4. What has Facebook said about the experiment?
In a post on his Facebook page, Adam Kramer, a Facebook data scientist who was involved in the study, apologized for upsetting users.
"Having written and designed this experiment myself, I can tell you that our goal was never to upset anyone," Kramer wrote. "I can understand why some people have concerns about it, and my coauthors and I are very sorry for the way the paper described the research and any anxiety it caused. In hindsight, the research benefits of the paper may not have justified all of this anxiety."