NYT: Chaser, a border collie who lives in Spartanburg, S.C., has the largest vocabulary of any known dog. She knows 1,022 nouns, a record that displays unexpected depths of the canine mind and may help explain how children acquire language. Chaser belongs to John W. Pilley, a psychologist who taught for 30 years at Wofford College, a liberal arts institution in Spartanburg. In 2004, after he had retired, he read a report in Science about Rico, a border collie whose German owners had taught him to recognize 200 items, mostly toys and balls. Dr. Pilley decided to repeat the experiment using a technique he had developed for teaching dogs, and he describes his findings in the current issue of the journal Behavioural Processes. 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 they 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,” Dr. Pilley said. “I’m 82, and I have to go to bed to get away from her.”