Because the human eye gaze is optimised for easy detection, it is often easy for us to work out whether someone is looking at us.... However, it turns out we can only reliably detect such gaze
within four degrees of our central fixation point.
However, we can use other cues to tell when someone is looking at us in our peripheral vision. Typically we also rely on the position or movement of their head (such as a turn towards you). We also rely on head or body cues when the potential watcher is in the dark or is wearing sunglasses. But, interestingly, you may not be right about being watched as often as you think. It turns out that in uncertain situations,
people systematically overestimate the likelihood that the other person is looking at them. This may be an adaptation to prepare us for interactions that are about to occur, particularly if the interaction may be threatening.
But what about the feeling that someone outside your field of vision, such as behind you, is watching? Is it really possible to “sense” that?... Sadly for those who wish we were X-men, it appears much of the body of research supporting the “psychic staring effect” appears to be suffering from
methodological issues, or
unexplained experimenter effects. For example, when certain experimenters act as the
watcher in these experiments, they seem to be more “successful” at getting people to detect their stares than other experimenters. It is almost certainly an unconscious bias, perhaps due to initial interactions with the experimenter.
Memory biases may also also come into play. If you feel like you are being watched, and turn around to check – another person in your field of view might notice you looking around and shift their gaze to you. When your eyes meet, you assume this individual has been looking all along. Situations where this happens are more memorable than when you look around to find no one looking at you.
