Your Brain Size Limits Your Number Of Friends

If you are envious of someone who seems to have hundreds of mates, don’t worry because they don’t really have a social network that big.

The truth is we all have a ‘happy hormone’ that limits the number of friends we can have at any one time.

Scientists have discovered that the chemical make-up in the brains of primates – humans, apes and monkeys – only allows us a close social circle of five to 15 people and a wider network of up to 150.

The number stops there because the size of our brains and the available time to maintain friendships limits a larger number of friends, says Professor Robin Dunbar, of Oxford University.

So anyone with the Facebook limit of 5,000 friends is probably kidding themselves and has 4,850 acquaintances rather than real mates.

Bonding mechanism

“Once you go beyond your close circle of friends of five to 15 people, it is less and less easy to use physical contact to trigger the endorphin system, not least because we just don’t have the time,” said Dunbar.

“But humans have found novel ways of doing this, including laughter, singing and feasting, that allow us in effect to ‘groom’ virtually with many people simultaneously, and this has allowed us to increase the size of our friendship circle up to 150.

“Primates have evolved a dual-process bonding mechanism partly dependent on advanced cognitive abilities – the social brain hypothesis, where we are making conscious, calculated decisions, often based on how much we can trust a person – and partly on the way we activate the endorphin system through social grooming.

“Our research shows that humans have extended these to allow us to form unusually large and structurally complex social groups.

Best number for groups

“This research shows how the conscious and subconscious parts of our brain work in tandem when it comes to making friends.

“It further demonstrates the best numbers for group sizes too; whether this be for measuring how many people to employ in a business, perhaps deciding on how many children you may want to have, or for military use when it comes down to deciding squadron numbers on the battlefield.

Looking beyond this it could be used to judge the effectiveness of large-scale society and how we manage to make mega communities such as the EU, and the United States of America, work.”