Broken Escalator Phenomenon

The broken escalator phenomenon is the sensation of losing balance, confusion or dizziness that some people report when stepping onto an escalator that is not working, a brief and odd sense of imbalance despite full awareness that the escalator will not move. The effect causes people to step inappropriately fast onto the stationary platform even when its stillness is obvious to them: although they are fully aware the escalator is not moving, parts of the brain still act on the prior experience of it moving, misjudging how to step onto it, which demonstrates the separateness of the brain's declarative and procedural functions. The phenomenon is the result of a locomotor after-effect that replicates the posture adopted to stabilize oneself when walking onto a moving platform; it was studied experimentally by Adolfo Bronstein and Raymond Reynolds in a paper published in 2003 and explored further in later experiments by Bronstein and colleagues, after being originally discussed by Brian Simpson in 1992, who named it the escalator effect and regarded it as the perceptual consequence of a failed expectation.