For a small study that tweaked the newsfeeds of less than 1 percent of the Facebook population, the so-called “emotional contagion” experiment has triggered a wave of attention — most of it negative — aimed at the giant social network and how it may or may not be affecting its users. But if nothing else, the research has at least shone a spotlight on the potential risks of that kind of behavior. in one of the more recent developments, a former Facebook data scientist confirms what many users suspected all along: if you have ever used Facebook, then you have probably been experimented on. Whether that’s a bad thing is still up for debate. Andrew Ledvina was quoted in a Wall Street Journal followup on the emotional contagion study, which removed certain phrases from the newsfeeds of about 700,000 users to see if it changed their behavior.