It pervades our thinking processes, from situations as simple as choosing which socks to wear in the morning to more nuanced scenarios like knowing to laugh during a wedding toast but not at a funeral.

The ability to make inferences from same and different, once thought to be unique to humans, is viewed as a cornerstone of abstract intelligent thought. A new study, however, has shown that what psychologists call same-different discrimination is present in creatures generally seen as unintelligent: newborn ducklings.

The study, published Thursday in Science, challenges our idea of what it means to have a birdbrain, said Edward Wasserman, an experimental psychologist at the University of Iowa who wrote an independent review of the study in the same issue.

“In fact, birds are extremely intelligent and our problem pretty much lies in figuring out how to get them to ‘talk’ to us, or tell us how smart they really are,” he said.