Crows can recognize geometric regularity

A trio of animal physiologists at the University of Tübingen, in Germany, has found that at least one species of crow has the ability to recognize geometric regularity. In their study published in the journal Science Advances, Philipp Schmidbauer, Madita Hahn and Andreas Nieder conducted several experiments that involved testing crows on their ability to recognize geometric shapes.

Recognizing regularity in geometric shapes means being able to pick out one shape that is different from others in a group—picking out a plastic star, for example, when it is placed among several plastic moons. Testing for the ability to recognize geometric regularity has been done with many animals, including chimps and bonobos. Until now, this ability has never been observed in any creature except for humans.

Because of that, the team started with a bit of skepticism when they began testing carrion crows. In their work, the testing was done using computer screens—the birds were asked to peck the outlier in a group; if they chose correctly, they got a food treat. The team chose to test carrion crows because prior experiments have shown them to have exceptional intelligence and mathematical capabilities.

All the birds tested caught on right away. Each could pick out a star if it was placed within a group of rectangles, for example. To determine their level of skill, the researchers started showing them objects that were only slightly different: one box that was tilted slightly, for example, among others that were not. Their accuracy went down, but it was still much higher than chance.

Continued testing showed that the birds had some understanding of right angles, parallel lines and even some degree of symmetry.

The research team suggests their experiments were quite convincing—the crows were very obviously able to recognize geometric regularity. They note that the experiments also showed that the birds could do so with no prior learning. The findings strongly suggest that the ability exists in other animals as well.

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