Study Finds Crows To Be Capable of Recursion — A Cognitive Ability Thought To Be Unique To Humans And Other Primates

OK, so what's recursion? It's the capacity to recognize paired elements in larger sequences – something that has been claimed as one of the key features of human symbolic competence. Consider this example: The rat the cat chased ran. Although the phrase is a bit confusing, adult humans easily get that it was the rat that ran and the cat that chased. Recursion is exactly this: pairing the elements rat to ran and cat to chased.