Agrillo studies something called numerical competence. That's essentially the ability to distinguish a small quantity from a larger one. The test his lab uses is fairly simple. Researchers place three black dots over a desirable object (like a plate of food or a door that leads to friends) and two dots over an undesirable object (like an empty plate or a door that leads to nowhere interesting). Agrillo and colleagues then look to see if, over multiple trials, the animals can distinguish between the two quantities. Besides fish, his team has worked with monkeys and birds - all of which have been fairly cooperative. But when he tried the experiment with cats, he practically gave up.
To reduce the number of variables, Agrillo's team always conducts the studies in its laboratory. But when owners brought their cats over, most of the felines freaked out. Even the docile ones displayed little interest in the test. Ultimately, Agrillo wound up with just four cats - and even they were a pain to work with. "Very often, they didn't participate in the experiment or they walked in the wrong direction," he told me. "It was really difficult to have a good trial each day." Still, he was able to get some results. Unlike fish, which can distinguish three dots from two, the cats paid more attention to the size of the dots than to their number. That makes sense when you consider that, in the wild, cats (unlike fish) live solitary lives and that when they hunt prey, they're more concerned about size than quantity. Counting just isn't that important to them.
Agrillo's work didn't break open the mystery of the feline mind, but at least it was something. I hoped Ádám Miklósi could provide me with a bit more. He's half the reason there has been so much work on the canine mind. In 1998, he and Duke University biological anthropologist Brian Hare independently showed that dogs can understand human pointing. Both labs conducted experiments demonstrating that when a volunteer pointed at one of two cups containing a treat, dogs almost always went for the correct cup. Though it may seem a simple test, our closest relatives, chimpanzees, fail miserably; they ignore the volunteer, pick cups at random, and rarely score above chance. The ability to follow a pointed finger isn't just a neat trick; it shows that dogs may have a rudimentary "theory of mind" - an ability to understand what another animal is thinking (in this case, that the human volunteer was trying to show them something). The skill is so important to our species that without it, we would have trouble learning and interacting with the world around us. That's why so many labs have begun studying the canine mind; dogs, the thinking goes, may provide clues to the evolution of the human mind.