Feeling Like Someone Is Watching You? Here's What Your Brain Is Doing

You are walking home alone when an odd sensation suddenly takes over. Nothing obvious has changed, yet you feel certain someone is behind you. You turn around and there is nobody there. For a moment, the feeling can be remarkably convincing. The brain is not simply a camera recording the world around us. It constantly predicts what might happen, monitors possible threats and interprets incomplete sensory information. That means a vague sound, movement in the corner of your vision or an uneasy feeling can sometimes be assembled into the impression that someone is watching. Usually, it is a perfectly ordinary example of the brain's protective instincts.