In 1998, Kingstone showed that people will automatically look where other people are looking. Other scientists have since found this gaze-copying behaviour among many other animals, from birds to goats to dolphins. It seems fairly obvious why we would do this—we get an easy clue about interesting information in the world around us. But what are we actually doing?

There are two competing answers. The obvious one is that we’re naturally drawn to people’s eyes, so we’ll automatically register where they’re looking. Indeed, one part of the brain – the superior temporal sulcus – is involved in processing the direction of gazes. The equally plausible alternative is that we’re focused more broadly on faces, and the eyes just happen