A team of scientists from the University of Sydney in Australia have found that while humans have the capacity to form complex layered societies, we face an upper limit to how many friends we can have in our inner circle.
They say this upper limit of five has likely gone unchanged for hundreds of thousands of years and probably governed social relationships when humans lived as groups of hunters.
The researchers built computer models to analyse human social networks and then compared them to hunter-gatherer societies.
They explain that from an evolutionary perspective, it was important to have small groups of close-knit social connections when humans were on hunting expeditions and other dangerous stations.
This would mean that we did not have to be as close with the rest of the wider group – as long as we had a strong bond with more or less five others.
Writing in the Journal of the Royal Society Interface, the researchers concluded that humans were probably egalitarian in hunter/gatherer-like societies, maintaining an average maximum of four or five social links connecting all members in a larger social network of around 132 people.
