A new study was published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS). The study is titled “Experimental evidence of massive-scale emotional contagion through social networks”, and it analyzes an experiment on Facebook users conducted by Facebook, in collaboration with researchers from UCSF and Cornell, almost two years ago. The experiment was a success, as it showed that Facebook was able to alter the emotional state of its users by making subtle and deliberate changes to the content users were shown in their news feeds. The study was subsequently edited for publishing by a Princeton professor, and accepted for publication by the prestigious National Academies , which by the way include the Institute of Medicine (IOM). The experiment “manipulated” the News Feeds of 689,003 people, randomly selected, and then measured the effect on the subjects’ own Facebook postings, due to increased exposure to either positive or negative content fr...