Why is it so unnerving to walk up or down a broken escalator?

It can be disconcerting to walk on broken escalator — even though an escalator that is not working is simply a set of stairs. 

On this week's instalment of "Yes, It's a Thing," a Sunday Edition mini-series that explores some of the strange things we experience without knowing if they're all in our heads, Michael discovers that this feeling has a name — broken escalator phenomenon — and it has been studied by academics. 

Dr. Raymond Reynolds lectures on the subject of motor control at the University of Birmingham in England. He was inspired to study the phenomenon by all the anecdotal reports he heard about people's discomfort walking on broken escalators in the London Tube. 

We were in no doubt that they believed it could not move, and yet they walked on to it as if it would move.- Dr. Raymond Reynolds

Dr. Reynolds explains that the odd sensation many people feel walking on a broken escalator is more than simply perceptual. Escalators accelerate riders' bodies, so to compensate and avoid falling backwards, riders lean forward and walk slightly faster. In a study, Dr. Reynolds and his colleagues found that even when people knew the escalator they were about to step on to was broken, they still accelerated as if they were stepping on to a moving escalator. 

Click the button above to hear this week's instalment of "Yes, It's a Thing."