In 1973, the sociologist Mark Granovetter published a paper called “The strength of weak ties” in which he put forward the idea that information largely spreads through society between individuals with weak connections rather than strong ties.

His evidence came from asking a few hundred people how they found their jobs. It turned out that the most common route was through vague acquaintances  rather than through strong friends.   Since then, Granovetter’s paper has become one of the most highly cited and influential in the field of social network theory.

But what of the role of strong ties? Today, Marton Karsai and pals at Northeastern University in Boston show that strong ties can actually hinder the spread of information through a network.

These guys looked at over 600 million time-stamped  mobile phone calls between 6 million people over six months in an unnamed European country. The analysis of these kinds of datasets has become common in recent years but Karsai and co have a new trick up their sleeves.