Asked by: Matt Taylor, Horley

This is called the ‘broken escalator phenomenon’. Each time we walk or ride on a moving escalator, our brains are learning to expect that escalators move. We then progressively fine-tune the motor control of our legs and the balance mechanisms of the inner ear to account for the motion. Even when we know that an escalator isn’t moving, our conscious awareness of this isn’t enough to override the unconscious brain that recognises the grooved metal staircase as an escalator and therefore expects it to move.

Scientists at Imperial College London investigated the phenomenon in 2004 and found that walking on a moving platform just 20 times was enough to condition the brain to expect it to still be moving on the 21st attempt, even though subjects were told in advance that it would not be.

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luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.