When it comes to your 'friends and followers' on Facebook and Twitter, the number may be gigantic. However, people still only have a handful of people they really consider good friends, a new University of Oxford study finds.
Despite the flurry of posts and photos on social media, the researchers found that people maintain the same number of close friends throughout their entire lives.
Each of us has what researchers call a unique "social signature," which we tend to keep throughout our lives by dropping old friends when new ones arrive, making the size of our inner circles mostly constant.
Findings were published this week in the journal Proceedings of the National Academy of Sciences.
Most people tend to have between about five and eight really close friends, says Felix Reed-Tsochas of the Said Business School at the University of Oxford.
"Although social communication is now easier than ever, it seems that our capacity for maintaining emotionally close relationships is finite."
"While this number varies from person to person, what holds true in all cases is that at any point individuals are able to keep up close relationships with only a small number of people, so that new friendships come at the expense of 'relegating' existing friends," he adds.
The study involved survey data and detailed data from mobile phone call records that were used to track changes in the communication networks of 24 students in the UK over 18 months as they made the transition from school or university to work.
At the beginning of the study, researchers "ranked" members of each participant's social network (friends and family) according to emotional closeness. They discovered that, in all cases, a small number of top-ranked, emotionally close people received a disproportionately large fraction of calls.
However, each subject had a characteristic social signature that depicted their particular way of allocating communication across the members of their social network, the researchers say.
Plus while each subject's relationships changed as they made new friends during the transition period between university and work, individual social signatures remained stable.
Participants continued to make the same number of calls to people according to how they ranked for emotional closeness, although the actual people in their social networks and/or their rankings changed over time.
"As new network members are added, some old network members are either replaced or receive fewer calls," adds researcher Robin Dunbar, professor of evolutionary psychology at Oxford. "This is probably due to a combination of limited time available for communication and the great cognitive and emotional effort required to sustain close relationships."