While the brain's ability to deal with abstract properties - including patterns of "same" and "different" - has been demonstrated in animals with advanced intelligence after extensive training, researchers now show that newly hatched ducklings can distinguish same and different, too, without any training at all. The ability to identify logical relationships between objects, retain this understanding, and apply it to novel objects is known as relational concept learning. To date, such learning - often mistakenly considered uniquely human - has only been demonstrated in a few animal species, and only after extensive reinforcement training. Here, working with ducklings, Antone Martinho III and Alex Kacelnik created a behavioral test involving the familiar social learning phenomenon of imprinting, one of the first things a naive brain learns to do (often in order to identify a parent). In the test, the first sight to which the newly hatched mallards were exposed was a pair of objects that were either the same or different in shape or color; later, when shown new pairs of objects, these ducklings preferred to follow pairs exhibiting the same relation on which they had originally imprinted. Thus, even imprinting, a most basic form of learning, appears to be shaped by higher level cognitive reasoning, the researchers say. In the wild, a young duckling being competent in relational thinking increases the likelihood that he will identify his mother and siblings, despite all variables the environment presents, the authors say. "This study is important for at least three reasons," Ed Wasserman notes in a related Perspective. "First... it indicates that animals not generally believed to be especially intelligent are capable of abstract thought. Second, even very young animals may be able to evidence behavioral signs of abstract thinking. And, third, reliable behavioral signs of abstract relational thinking can be obtained without deploying explicit reward-and-punishment procedures."