Dumb cluck. Birdbrain. Chickens aren't considered a very intelligent species, as epithets like these suggest. But Italian neuroscientist Giorgio Vallortigara is turning that conventional wisdom on its head. He says that newborn chicks are natural mathematicians and intuitive physicists.
Vallortigara's lab is in the cellar of a sixteenth-century convent in Rovereto, an Italian town in the foothills of the Alps. A dapper man in a light-blue shirt and silk tie, he was born here in the decade after World War II, when Italy was poor and flocks were critical to survival. "Not to have chickens was not to have eggs," he says, and that often meant going hungry. As a child, he grew curious about how animals like the common fowl perceived the world.
The idea that animals have mental abilities similar to those of humans has been controversial since the seventeenth-century French philosopher René Descartes declared that they lack minds, reason, and a soul. Animals communicate anger, fear, or hunger with sounds, he noted, but they don't speak and therefore lack the inner voice that is the very basis of human thought. His famous "I think therefore I am" might be better stated as "I speak therefore I am." Animals might feel pain or pleasure-"I deny sensation to no animal," he wrote-but they lack that human quality of greater awareness or cognition. Philosophers, scientists, religious figures, and animal activists have been arguing this point ever since.
Neuroscientists like Vallortigara are gathering hard data on animal perception to shed new light on the old debate. In a series of simple experiments, he showed that newborn chicks could track little plastic balls appearing and disappearing behind screens, even when he tried to fool them by moving some balls to another screen. Humans generally fail at the task until they are four years old.
Chicks also are capable of adding and subtracting. A young bird presented with an identical cylinder that disappears behind one screen and several that disappear behind the other screen will go to the screen with the larger number of cylinders. If the researchers move a cylinder from one screen to the other, so that the second screen holds more objects, the chick will go to the screen with the most objects. In another experiment, six identical containers are set up in an arc, all of which are the same distance away from the bird but only one of which has feed, and the chick is allowed to find which one has the food. Switch the food container to another position, and the chick will still choose the correct one.
He also is conducting experiments on filial imprinting, in which newly hatched birds attach themselves to the first moving object they see. The researchers show a chick a particular object such as a red cylinder, place the animal in a transparent pen, and hide the cylinder behind one of two opaque screens. The transparent pen then is covered with a screen, and after a delay of up to one minute, they let the chick go to the screen of its choice. The bird finds the imprinted object on the first try, demonstrating a well-developed memory. In another experiment, the cylinder is hidden behind a screen that covers the entire object, while the neighboring screen has a different height or width that would reveal a portion of the object. The bird invariably picks the one disguising the cylinder, a sign of what Vallortigara calls "an intuitive physics."
The birds can understand geometry, recognize faces, retain memories, and make logical deductions that Vallortigara insists exceed the capabilities of some of his graduate students. The chick recalls faces of humans and chickens, and can respond to that individual based on a previous experience. Seeing a favorite hen, for example, will cause a rooster's sperm production to suddenly increase.
Other neuroscientists are finding that chickens practice self-control, alter their message to fit the receiver, and, in some instances, can feel empathy. Some of these cognitive abilities equal or surpass those of assorted primates, and it is possible that the chicken possesses a primitive self-consciousness. So next time you are tempted to use the chicken as the epitome of cluelessness, consider the evidence.
Andrew Lawler is author of Why Did the Chicken Cross the World? The Epic Saga of the Bird that Powers Civilization published today by Atria division of Simon and Schuster. For more, see www.andrewlawler.com.