You're in a long, boring meeting. You look up at the clock again, hoping time is passing by faster than it feels, but instead the clock's seconds hand doesn't seem to move at all. No, the clock didn't just pause to mock you, your brain is playing tricks on you.
Photo by Phalinn Ooi.
According to Amelia Hunt, a neuroscientist at the University of Aberdeen, the phenomenon is known as the "stopped-clock illusion". As Hunt explains to Popular Science, the pause happens when our brains anticipate what we'll see faster than we actually see it. That's right — your brain tries to predict what you're going to see before your gaze gets there. Why? When you move your eyes, everything you're seeing shifts position in your eyes, creating a different image in your brain. Your brain anticipates some of those adjustments as your eyes move and updates your mental map of where your brain thinks everything is positioned so you don't feel disoriented.
When it comes to looking away from a clock and back again, your brain is already thinking ahead almost half a second, predicting where the seconds hand is going to be based on what you've already seen. By the time your eyes line up with the clock again, the seconds hand will seem to hang there for an extra moment before continuing on normally because you've anticipated it to be there. So don't panic — what you're seeing is perfectly normal. If you start to see the clock running backwards, though, maybe worry a little.
When time seems to stop, blame your over-prepared brains [Popular Science]