Judging knots throws people for a loop

The researchers showed people pictures of two knots and asked them to point to the strongest one. They can’t.

They showed people videos of each knot in which the knot was slowly rotated so they could watch it for a long time. They still failed.

When researchers showed people each knot along with a diagram of the knot’s structure, people couldn’t even do that.

“People are terrible at this,” said Chaz Firestone, a co-author who studies perception. “Humans have been using knots for thousands of years. They’re not that complicated – they’re just ropes tangled together. However, you can show people real pictures of knots and ask them how they behave towards them. of any judgment, and they don’t know.

The work is newly published in the journal Cognitive Science open mindreveals a new blind spot in our physical reasoning.

The experiment is the brainchild of Sholei Croom, a doctoral student in Firestone Labs who happens to be an avid embroiderer. Klum was working on a project, turned it over to a complex and daunting tangle of embroidery thread, and couldn’t make sense of it—even though it was Klum’s own craft. Crum, who studies intuitive physics, or the knowledge people can gain about their environment simply by looking at it, suspected that knots might be a rare form of vulnerability.

“People have been predicting how the physics of the world will develop, but something about knots is not intuitive to me,” Croom said. “You don’t need to touch a stack of books to judge its stability. You don’t need to touch a bowling ball to guess how many pins it will knock over. But knots seem to strain our judgment mechanisms in interesting ways.”

The experiment was simple: Researchers showed participants four knots that were physically similar but ranked in strength. People were asked to look at the knots, two at a time, and point to the strongest one.

The participants are always wrong. What’s more, there were a few times where they guessed correctly, but they did so for the wrong reasons, pointing out aspects of the knot that had nothing to do with its strength.

These knots range from the Reef Knot, one of the strongest basic knots in existence, to one so weak that it can be untied with just a gentle push – the aptly named Sadness Knot. Even if the two stand side by side, people can’t tell who is the strongest.

“We tried to give people the best chance in the experiment, including showing them videos of the knots spinning, but that didn’t help at all — if anything, people responded even more confusingly,” Crum said. “The human mental system cannot determine any physical knowledge from the properties of knots.”

Crumb said nonrigid objects, such as ropes, can be more difficult for people to reason about than solid objects. Not even our extensive experience with tying shoelaces and untying rope knots can overcome this flaw, although Crum speculates that sailors or survivalists who rely on knot strength for a living might perform better in experiments than the non-Knots tested. Experts perform better.

“We just can’t look at the knot to extract the salient features of its internal structure,” Crum said. “This is a great case study of how many open questions remain in our ability to reason about environments.”