How many of your Facebook friends are real friends? In other words, how many of your online friends would help if you were in trouble? Professor of evolutionary psychology Robin Dunbar put that question to the test. Citing a "dramatic revolution in our social world," he wondered if the size of your social media network had any correlation to having more friends in real life.

The average number of Facebook friends possessed by people was around 150. But, out of those 150, only 28, on average, we recognized as low-level "friends." But when participants were asked how many of those friends would help out in a time of need, emotional distress, or other crisis, the average answer was four. Around 14 would at least express sympathy.

We might have 150 or even 5,000 Facebook friends, but our true relationship with the majority of these people is essentially insignificant.