"There is a widespread belief that software and algorithms that rely on data are objective. But software is not free of human influence. Algorithms are written and maintained by people, and machine learning algorithms adjust what they do based on people’s behavior. As a result, say researchers in computer science, ethics and law, algorithms can reinforce human prejudices."

"To demonstrate how reality may differ for different Facebook users, The Wall Street Journal created two feeds, one “blue” and the other “red.” If a source appears in the red feed, a majority of the articles shared from the source were classified as “very conservatively aligned” in a large 2015 Facebook study. For the blue feed, a majority of each source’s articles aligned “very liberal.” These aren't intended to resemble actual individual news feeds. Instead, they are rare side-by-side looks at real conversations from different perspectives."