Intruder detection task. Two pealed crows were trained to detect an intruder stimulus in a table of six stimuli presented simultaneously. The crows launched the test by moving their heads in front of the screen whenever a stimulus Go appeared. After a period of 200 ms prestimulus, a table of six stimuli was displayed. The crows responded by pricking the intruder. In 50% of the tests, the crows were tested with non -quadrilateral background stimuli (above); In this example, the croissant is the intruder among the stars. In the remaining 50% of the tests, the crows were tested with stimuli of quadrilateral probe (below); In this example, a non -symmetrical quadrilateral is the intruder among symmetrical quadrilaterals. Credit: Scientific advances (2025). DOI: 10.1126 / SCIADV.ADT3718
A trio of animal physiologists from the University of Tübingen, Germany, noted that at least one species of crow has the ability to recognize geometric regularity. In their study published in the journal Scientific advancesPhilipp Schmidbauer, Madita Hahn and Andreas Nieder conducted several experiences that consisted in testing the crows on their ability to recognize geometric forms.
Recognizing the regularity of geometric forms means being able to choose a different form of others in a group – select a plastic star, for example, when it is placed among several plastic moons. Testing the ability to recognize geometric regularity has been carried out with many animals, including chimpanzees and bonobos. So far, this capacity has never been observed in any creature, except for humans.
For this reason, the team started with a little skepticism when it started to test Carrion crows. In their work, the tests were carried out using computer screens – the birds were invited to peck the aberrant value in a group; If they chose properly, they obtained food treat. The team has chosen to test the Carrion Ravens because previous experiences showed them that they had exceptional intelligence and mathematical capacities.
All the birds tested immediately took. Everyone could choose a star if it was placed in a group of rectangles, for example. To determine their level of competence, the researchers began to show them objects that were only slightly different: a box that was slightly tilted, for example, among others. Their precision has dropped, but it was still much higher than chance.
Example of a provision of canonical probe stimulus. Here, a deviant shape (in the upper left position) was placed in the middle of five reference forms with a right hinge and had to be recognized as the intruder. Credit: Scientific advances (2025). DOI: 10.1126 / SCIADV.ADT3718
Continuous tests have shown that birds had a certain understanding of right angles, parallel lines and even a certain degree of symmetry.
The research team suggests that their experiences were quite convincing – the crows were very obviously able to recognize geometric regularity. They note that experiences have also shown that birds could do it without prior learning. The results strongly suggest that the capacity also exists in other animals.
(A) Test stimulus set. The crows were tested with a set of stimulus composed of five pairs of non -quadrilateral shapes used as a familiar background stimuli which had been used during training (left) and five pairs of quadrilateral shapes used as probe stimuli (right). (B) The five quadrilateral reference forms used to test the gap with respect to geometric regularity. From left to right, the quadrilaterals were more and more different in geometric properties (parallelism, symmetry, perpendicularity, equal and equal angles). Here, they are ordered from left to right by reducing regularity. Credit: Scientific advances (2025). DOI: 10.1126 / SCIADV.ADT3718
More information:
Philipp Schmidbauer et al, Crows recognize geometric regularity, Scientific advances (2025). DOI: 10.1126 / SCIADV.ADT3718
© 2025 Science X Network
Quote: Crows can recognize geometric regularity (2025, April 14) recovered on April 15, 2025 from
This document is subject to copyright. In addition to any fair program for private or research purposes, no part can be reproduced without written authorization. The content is provided only for information purposes.
