Broken escalator phenomenon

The broken escalator phenomenon is the result of a locomotor after-effect which replicates the posture adopted when walking onto a moving platform to stabilise oneself.

The phenomenon was originally discussed by Brian Simpson (1992) who named it the "escalator effect" and regarded it as the perceptual consequence of a failed expectation.

When facing an external threat to our balance, our central nervous system will trigger neural processes in order to stabilise our posture.

[1] Thus, when we step onto a moving escalator, we alter our posture and gait in order to stabilise ourselves against this external threat to our balance.

This resulted in them walking inappropriately fast and excessively swaying their torso when stepping onto the sled, leading to a sensation of dizziness.

The broken escalator phenomenon is the result of the dissociation between the declarative and procedural functions of the central nervous system.

[5] The fact that we walk inappropriately fast onto an escalator we know to be broken is evidence of motor adaptation without declarative memory.

The person undertakes a 'worst-case scenario' which seems the most strategic option: preparing for the platform to move even though it won't is better than the opposite.

[7] However, another experiment demonstrated that the aftereffect was not as intense when subjects walked onto the stationary sled with the opposite leg of the one they'd stepped with in the MOVING trials.