Pigeons can tell impressionism and cubism apart

A series of experiments with pigeons carried out in the 1970s piqued researcher Vokey's curiosity about tacit learning. In the experiments, pigeons were shown two photos, one of which contained a particular feature that the other did not -- for instance, a human, a tree or a body of water. The birds could choose between the photos by pecking at a button, which would reward them with food if they chose the picture that contained the feature of interest. It turned out that the animals were quickly able to distinguish between the photos, even when they were shown new sets of pictures.

Experiments with wild pigeons that had never been handled by humans demonstrated that wild birds could also learn to distinguish between sets of photos that were projected on to an office window. In a later experiment, pigeons were trained to discriminate between a set of paintings by Pablo Picasso and a set of paintings by Claude Monet. After a brief training period, the birds were shown entirely different paintings by the same artists, and they were still able to make the distinction between the artists' works. Further studies suggested that if other cubist or impressionist artists replaced the Picasso and Monet paintings, the birds were still able to choose the correct painting.

"The research suggests that they learned something about elements of style," says Vokey. "We like to think that this is an intellectually deep exercise, but the fact that pigeons can do it suggests that judgments of style may be much simpler."