Animal talk

He bought Chaser as a puppy in 2004 from a local breeder and started to train her for four to five hours a day. He would show her an object,say its name up to 40 times,then hide it and ask her to find it,while repeating the name all the time. She was taught one or two new names a day,with monthly revisions and reinforcement for any names she had forgotten.

Border collies are working dogs. They have a reputation for smartness,and are highly motivated. They are bred to herd sheep indefatigably all day long. Absent that task,they must be given something else to do or they go stir crazy. Chaser proved to be a diligent student. Unlike human children,she seems to love her drills and tests and is always asking for more. She still demands four to five hours a day, Pilley said. Im 82,and I have to go to bed to get away from her.

One of Pilleys goals was to see if he could teach Chaser a larger vocabulary than Rico acquired. But that vocabulary is based on physical objects that must be given a name the dog can recognise. Pilley found himself visiting Salvation Army stores and buying up sackfuls of used childrens toys to serve as vocabulary items. It was hard to remember all the names Chaser had to learn,so he wrote the name on each toy with indelible marker. In three years,Chasers vocabulary included 800 cloth animals,116 balls,26 Frisbees and a medley of plastic items.

Children pick up about 10 new words a day until,by the time they leave high school,they know around 60,000 words. Chaser learned words slowly but faced a harder task: Each sound was new and she had nothing to relate it to,whereas children learn words in a context that makes them easier to remember. For example,knives,forks and spoons are found together.

Pilley does not know how large a vocabulary Chaser could have mastered. When she reached 1,000 items,he grew tired of teaching words and moved to interesting topics like grammar. He taught Chaser three different actions: pawing,nosing and taking an object. She was then presented with three of her toys and correctly pawed,nosed or fetched each one depending on the command given to her. That experiment demonstrates conclusively that Chaser understood that the verb had a meaning, Pilley said.

Haunting almost every interaction between people and animals is the ghost of Clever Hans,a German horse that in the early 1900s would tap out answers to arithmetic problems with his hoof. The psychologist Oskar Pfungst discovered that Hans would get the answer right only if the questioner also knew the answer. He then showed that the horse could detect minute movements of the questioners head and body. Since viewers would tense as Hans approached the right number of taps,and relax when he reached it,the horse knew exactly when to stop.

People project their expectations onto animals,particularly dogs,and can easily convince themselves the animal is achieving some humanlike feat when in fact it is simply reading cues unconsciously given by its master. Even though researchers are well aware of this pitfall,interpreting animal behavior is particularly tricky. In the current issue of Animal Behaviour,a leading journal,two previous experiments with dogs have been found wanting.

Juliane Kaminski,a member of the research team that tested Rico,was well aware of the Clever Hans effect. So she arranged for the dog to be given instructions in one room and to select toys from another,making it impossible for the experimenter to give Rico unwitting cues. Dr Kaminski works at the Max Planck Institute for Evolutionary Anthropology in Leipzig,Germany. Pilley took the same precaution in testing Chaser.

The learning of words by Rico and Chaser may have some bearing on how children acquire language,because children could be building on the same neural mechanisms. Pilley concludes that his experiments provide clear evidence that Chaser acquired referential understanding of nouns,an ability normally attributed to children.

But the experiments relevance to language is likely to be a matter of dispute. Chaser learns to link sounds to objects by brute repetition,which is not how children learn words. And she learns her words as proper nouns,which are specific labels for things,rather than as abstract concepts like the common nouns picked up by children. Kaminski said she would not go as far as saying that Chasers accomplishments are a step toward language. They show that the dog can combine words for different actions with words for objects. A step toward syntax,she said,would be to show that changing the order of words alters the meaning that Chaser ascribes to them.

Pilley says he is working on just that point. Were trying to teach some elementary grammar to our dog, he said. How far well be able to go we dont know,but we think we are on the frontier. His goal is to develop methods that will help increase communication between people and dogs. We are interested in teaching Chaser a receptive,rudimentary language, he said. NICHOLAS WADE