Even if you have thousands of Facebook friends, you can probably only count on a handful in a pinch, according to a new study. The author, anthropologist Robin Dunbar, should know. He’s the guy who came up with Dunbar’s number, which shows that in the real world, people can only maintain about 150 stable relationships. For his latest research, Dunbar analyzed a UK study of 3,375 Facebook users between the ages of 18 and 65. On average, folks had 150 followers but said that they could only count on 4.1 of them during an “emotional crisis,” and only 13.6 ever express sympathy.