ELi5: Why is it hard to tangle something on purpose but easily gets entangled by itself?


Like my chargers and earphones get tangled and hard to take apart in my pocket or backpack. But if I try to replicate it, it’s way harder.

In: 1

I feel like it’s issue with topography… Cables in pocket don’t usually tie knots 🪢. Wires just pass each other back and forth.

When you “untangle” them, you accidentally make it was worse by pulling in wrong direction

The answer is a bit of physics and a bit of psychology.

From a physics/math perspective, there’s a lot of ways for a rope, string, etc. to be tangled and few ways for it to be untangled. So given some agitation (effectively, letting the rope move around arbitrarily), the rope will more often end up in a tangled state than an untangled one. Making matters worse, there’s typically only one *path* back from a tangled state, and many paths that lead to more tangled states. So once the rope has wound up tangled, it’s very unlikely to untangle itself from arbitrary movement.

From a psychological perspective, there’s also the matter of where you’re directing your attention. If you sit there shaking your headphone cords for a minute, they might tangle or they might not, but it feels like you spent a while trying because you were focused on it. When you put your neatly coiled headphones in your pocket and go about your day for the next 6 hours, you’re not thinking about how you’re giving your headphones 6 hours to tangle up. You just notice they’re tangled 6 hours later when you pull them out. It’s similar to confirmation bias. If you sat there tossing your headphones around for 6 hours, they’d surely tangle at some point. But it would feel like a lot more effort than just sticking them in your pocket and coming back later.