Spoiler alert: They're not your real friends.
Do you have a lot of Facebook friends? How many do you consider real friends? How many would take you to the emergency room if you cut your hand, or listen to you while you told them about your latest heartbreak?
A study published in The Royal Society Open Science Journal says that while you may have hundreds of Facebook friends, you can only really depend on four of them, on average.
The study's lead researcher and Oxford psychologist Robin Dunbar analyzed a survey of 3,375 Facebook users in the United Kingdom. He found that, despite having about 150 Facebook friends on average, the study's subjects would only turn to about four of those friends in a time of emotional crisis and could rely only on about 14 for sympathy. In addition, the average person said that only about 27 percent of their Facebook friends were genuine.
Instead of increasing people's real-time social circles, Dunbar suggests that Facebook and other social media can help to prevent friendships fading away over time.
"Friendships, in particular, have a natural decay rate in the absence of contact, and social media may well function to slow down the rate of decay," Dunbar wrote. "However, that alone may not be sufficient to prevent friendships eventually dying naturally if they are not occasionally reinforced by face-to-face interaction."
In other words, don't depend on your Facebook friends to bring you chicken soup when you've got the flu, but do use social media as a way to keep in touch and keep the flame of your real relationships burning.
Here's Professor Dunbar's TEDTalk about why Facebook won't garner you any more friends:
All relationships take an investment of time and attention, and social media doesn't change that. If all you're doing is reading someone's status or commenting on a picture they've posted, you're not really connecting with them on a real level.
"When you need that shoulder to cry on, you need a real shoulder — a virtual shoulder simply doesn't do the job," Dunbar said.