Researchers find birds can theorize about the minds of others, even those they cannot see |

The question of what sets humans apart from other animals is one of the oldest philosophical puzzles. A popular answer is that only humans can understand that others also have minds like their own.

But new research suggests that ravens - birds singled out by many cultures as a symbol of intelligence and wisdom - share at least some of the human ability to think abstractly about other minds, adapting their behavior by attributing their own perceptions to others.

The study, "Ravens Attribute Visual Access to Unseen Competitors," was published Feb. 2 in Nature Communications. It found that ravens guarded caches of food against discovery in response to the sounds of other ravens if a nearby peephole was open, even if they did not see another bird. They did not show the same concern when the peephole was closed, despite the auditory cues.

The findings shed new light on science's understanding of Theory of Mind, the ability to attribute mental states - including vision - to others, said Cameron Buckner, assistant professor of philosophy at the University of Houston. Buckner is an author of the paper, along with Thomas Bugnyar and Stephan A. Reber, cognitive biologists at the University of Vienna.