Whether it’s tying your shoelaces or doing up your tie, many of us use knots on a daily basis.
Despite this, research has shown that humans are ‘terrible’ at judging knots.
Scientists from Johns Hopkins University showed participants pictures of knots and asked them to point out the strongest one.
Amazingly, they found that most people struggled to tell a weak knot from a strong one.
‘People are terrible at this,’ said Chaz Firestone, co-author of the study.
‘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.’
So, can you tell which of these four knots is the strongest? Scroll down for the answer!
Can you tell which of these four knots is the strongest? Scroll down for the answer
The study was led by Sholei Croom, a PhD student who set out to investigate how humans perceive knots.
‘People make predictions all the time about how the physics of the world will play out but something about knots didn’t feel intuitive to me,’ Ms Croom said.
‘You don’t need to touch a stack of books to judge its stability.
‘You don’t have to feel a bowling ball to guess how many pins it will knock over.
‘But knots seem to strain our judgment mechanisms in interesting ways.’
The team enlisted 50 participants, who were shown four knots and asked to pick which was the strongest.
Physically, all four knots were similar, but where they differed was in their strength – the force needed to untie them.
For example, the reef knot is the strongest knot in existence, while the grief knot can be unravelled with a gentle nudge.
To simplify things, the researchers next showed the participants pitures of just two knots and asked them to point out the strongest one
The results revealed that the participants were consistently unable to correctly identify the strongest knot.
To simplify things, the researchers next showed the participants pictures of just two knots and asked them to point out the strongest one.
Again, they couldn’t.
Finally, they showed participants videos of each knot, where the knots were slowly rotated so they could get a proper look from every angle.
Once again, the participants were unable to pick the strongest knot.
‘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,’ Ms Croom said.
‘The human psychological system just fails to ascertain any physical knowledge from the properties of the knot.’
While the reason for the findings remains unclear, the researchers suggest that objects that aren’t rigid – such as rope or string – may be harder for people to reason about.
‘We’re just not able to extract a salient sense of a knot’s internal structure by looking at it,’ Ms Croom added.
‘It’s a nice case study into how many open questions still remain in our ability to reason about the environment.’
The answers
1. Knot A is the strongest
2. The reef knot (top) is substantially stronger than the grief knot (bottom)
