BY THE OPTIMIST DAILY EDITORIAL TEAM
Humans have long assumed we hold a monopoly on recognizing shapes with geometric regularity. But a new study challenges that belief, revealing that crows can distinguish symmetrical, four-sided figures from irregular ones, suggesting that the foundations of geometric thinking may extend far beyond our species.
“Claiming that it is specific to us humans, that only humans can detect geometric regularity, is now falsified,” says Andreas Nieder, a cognitive neurobiologist at the University of Tübingen in Germany. “Because we have at least the crow.”
This remarkable discovery, published in Science Advances, marks the first time that any non-human species has demonstrated this specific form of visual and mathematical insight. While other animals have been tested for various cognitive skills, this kind of geometric intuition has largely flown under the radar.
Testing the geometric minds of crows
The study focused on two carrion crows living in Nieder’s lab. These birds aren’t new to the spotlight—they’ve previously demonstrated counting abilities that rival those of toddlers.
In this experiment, the crows were shown sets of six shapes on a computer screen. Their task? Peck the shape that didn’t match the others to earn a mealworm treat.
“Initially, we presented some very obviously different figures,” explains Nieder. “For instance, five moons and one flower.”
But after the birds learned the basic rules of the game, the challenge increased. The researchers began showing the crows more subtle variations: sets of quadrilaterals, such as five perfect squares alongside one irregular four-sided shape.
Could the birds still spot the odd one out, even when the difference was minimal?
Yes, they could.
According to the researchers, the crows reliably identified shapes that lacked regular features like parallel lines, right angles, or symmetry. This means they weren’t just guessing or reacting to visual novelty—they had an abstract understanding of geometric consistency.
Why this discovery matters
Before this study, no animal had demonstrated the ability to recognize geometric regularity in this way. In fact, even baboons—primates far more closely related to humans than birds—have struggled with similar tasks.
Mathias Sablé-Meyer, a cognitive neuroscientist at University College London who previously worked on a study involving baboons, expressed his surprise at the findings. “After failing to train the baboons to do it, I wouldn’t have expected crows to do it,” he admits. Still, he finds the evidence compelling. “The evidence is actually quite convincing. I have to accept the result and think, you know, that’s pretty cool!”
The results suggest that crows possess a surprisingly abstract form of pattern recognition. If birds can understand symmetry and right angles, perhaps geometric thinking didn’t begin with humans after all.
Opening new doors in animal cognition
Nieder sees this study as just the beginning. “I would never dare to say that this is the only species,” he says. “It’s just now opening this field of investigation.”
He hopes other researchers will begin exploring geometric reasoning in different animals. If similar abilities are found in other intelligent species, it could reshape how scientists think about the evolution of mathematical and spatial cognition.
“I’m pretty sure they may find that other intelligent animals can also do this,” says Nieder.
For now, the crows have offered a stunning reminder: intelligence doesn’t always follow a straight line, but sometimes, it can recognize one.
Source study: Science Advances—Crows recognize geometric regularity
