“This is really much harder than climbing stairs,” complain the teenage girls in the TikTok video as they trudge up a broken escalator. What makes this so difficult?
“A silent escalator certainly has more gravity,” someone comments under the video. Nah, it won’t be. Then google it again.
‘Broken escalator’ appears to be a frequently used term, also in scientific articles. But they are not about the difficult climbing, but about another phenomenon: that you often lose your balance for a moment when you step on a stationary escalator. Or off again.
The psychologist Brian Simpson wrote already in 1992 about what he called the “escalator effect.” According to him, it is due to wrong expectations: “We are so used to being thrown forward by a moving escalator that our brains automatically compensate for the expected sensation and cancel it out with a kind of conditioned mental reflex.”
Psychology and motor skills
A psychological effect, an illusion, that takes place purely in your brain. No, Oxford neurologists concluded in 2003 a few experiments. It is a combination of psychology and motor skills. Normally you unconsciously compensate for the forward movement of the escalator by stepping on it with a little extra speed. But now you step on a stationary escalator. You see that it is standing still, so you know that you are not going to be pulled forward, but you still automatically compensate for that anticipated movement. That’s why you still get on the escalator a little faster. Too fast for a stationary step. You are shocked and compensate with muscles in your upper body and legs. That feels strange.
Frank Zaal, sports scientist at the UMC Groningen, investigates the interaction between perception and movement. “What I find very interesting,” he says, “is how people control their movements based on incoming information, and vice versa, how your own movements also influence that incoming information.”
As an example he mentions catching a baseball while running. You and the ball both move, and as a result of both movements, the image on your retina changes. You automatically adjust your movements in such a way that you can catch the ball. “Very wonderful actually. After all, your brain does not have a theoretical model of ball trajectory and air resistance.”
Calibration is no longer correct
So there is a complex interplay between what you see, expect and physically feel – often unconsciously. “I suspect that something similar is also happening when stepping on a stationary escalator,” says Zaal. “That reminds me of a 1995 study in which people walked on a treadmill pulled by a tractor. After that, their calibration of speeds and distances was no longer correct.”
This also makes it plausible that walking up a stationary escalator seems more difficult: after all, you gain less height per step than you expect. “It may also have to do with the wrong step height,” says Zaal. “I think those steps are mainly designed to move around as best as possible in that turning mechanism. Not at the ideal step height.” And what is the ideal step height? “Nice studies have also been published about this. Your ideal step height is a function of your leg length, so it’s different for everyone, according to a 1984 study. Others saw a connection with eye level. People appeared to be unable to climb stairs properly with blocks under their feet. But after a while those people get used to it. That is the aforementioned calibration.”