Your Facebook page may boast a small army of friends, but to your brain it's the same as it ever was.
Back in the early 1990s, when the web and social media were still in their infancies, a psychologist named Robin Dunbar uncovered something intriguing about brain size and structure. He found that the size of the most recently evolved part of the brain, the neocortex, correlates closely with the relative size of social groups. First he identified the correlation in primates, then reasoned that the same should apply to humans. He was right. In humans throughout history, he observed, the sweet spot for social group size has consistently been between 100-200 relationships.
Thus, what we know as “Dunbar's Number” was born: the human brain seems calibrated to effectively handle around 150 relationships of varying depths (some shallow, some strong).
But our social media experience seems to contradict Dunbar’s findings. As tools for extending our relationship reach, Facebook and other sites theoretically allow us to leverage our limited resources to maintain more relationships in less time. Perhaps technology has enabled us to turn a corner, cognitively speaking, and go beyond the constraints that have kept human social groups relatively contained for centuries.
Well, who better to test that theory than Robin Dunbar himself? To do so he relied on a survey from an unlikely source, the Thomas J. Fudge biscuit company in Britain. The survey was well-structured, randomly sampling 2,000 regular social network users across the country and another 1,375 who weren’t necessarily regular social media users (the second group was more representative of the population overall). Survey questions delved into how many friends respondents had on Facebook and the relative closeness of those friendships.
Post analysis, the results showed that despite the numbers on our Facebook pages, we modern humans are much like humans of centuries past. The true numbers of friendships across the studied groups was still between about 150 and 180 people. Respondents in the most active social media group said that on average only about 28% of their Facebook friends could be considered “genuine." And drilling down further, respondents confirmed that really only about 15 of those people could be called “close friends."
The bottom line: no matter what social media numbers publicly portray, our brains still hue to a relatively constrained number of relationships, much as they always have.
Dunbar commented in the study: “The fact that people do not seem to use social media to increase the size of their social circles suggests that social media may function mainly to prevent friendships decaying over time in the absence of opportunities for face-to-face contact.”
The study was published in the journal Royal Society Open Science.