When you tie your shoes or you attempt to secure a rope to keep your boat in place, you know that the knot you are using should hold tight, at least for a while.

If you come across an existing knot, however, the chances are that you will have no idea how strong that knot will be. This has been proven in a new study published in the journal Open Mind.

The study was based on a project made by Sholei Croom. Croom is a PhD student at Johns Hopkins University and studies intuitive physics, which is an area of study that looks at how well humans are able to understand certain aspects of their environment just by looking at it.

While people are great at certain things, they are terrible at knowing which knots are the best. This was determined by showing participants of the study four knots that each had different strengths. They were asked to pick which one was the strongest.

They failed miserably. Even when they guessed right, they were right for the wrong reasons.

The test was done again only this time the participants were able to see a video of each knot. The video would rotate all around the knot so they could see every aspect of it.

They still failed.

Chaz Firestone is a co-author of the study. He also researches at Johns Hopkins University, studying perception. In a statement, he said:

“People are terrible at this. Humanity has been using knots for thousands of years. They’re not that complicated – they’re just some string tangled up. Yet you can show people real pictures of knots and ask them for any judgment about how the knot will behave and they have no clue.”

This wasn’t a trick study either. They really did everything that they could to ensure the participants had every opportunity to succeed. Croom commented on this, saying:

“We tried to give people the best chance we could in the experiment, including showing them videos of the knots rotating and it didn’t help at all – if anything people’s responses were even more all over the place. The human psychological system just fails to ascertain any physical knowledge from the properties of the knot.”

He went on to say:

“We’re just not able to extract a salient sense of a knot’s internal structure by looking at it. It’s a nice case study into how many open questions still remain in our ability to reason about the environment.”

So, the next time you see something secured with a knot, do not assume you know how safe it really is.

You better KNOT test that rope.

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