A border collie in Spartanburg, North Carolina, has been reported to have the largest vocabulary of any known dog. Chaser, owned by psychologist Dr John W. Pilley, knows over 1,000 different nouns taught to her by Dr Pilley over a period of three years.
After Dr Pilley retired in 2004, he read a report in ‘Science’ journal about Rico, a border collie from Germany whose owners had taught him to recognize 200 items. Dr. Pilley decided to repeat the experiment using his background in psychology and his own training methods.
Chaser was bought by Dr Pilley as a puppy in 2004 from a local breeder and started training her right away. The training sessions were 4 – 5 hours a day and he would show her an object and repeat the chosen name up to 40 times. Dr Pilley would then hide the object and ask her to find it, while repeating the name throughout the locating process. She was taught one or two new names a day on average, with monthly tests and he would retrain her for any of the names she had forgotten.
One of Dr. Pilley’s goals was to see if he could teach Chaser to respond appropriately to a larger vocabulary than Rico acquired. As the vocabulary taught to Chaser was noun-based, he found himself running out of items quickly to teach her new words, as every vocal cue or ‘name’ had to be different. Dr. Pilley found himself visiting Salvation Army stores and purchasing large quantities of used children’s toys to serve as vocabulary fodder. He found it hard to remember all the exact names Chaser had been taught for individual items, so he wrote the name on each toy with marker. In these three years, Chaser’s vocabulary included 800 plushie/cloth toys, 116 balls, 26 Frisbees and a medley of plastic items.
Studies show that children learn new words every day until, by the time they reach eighteen years of age, they know approximately 60,000 words. Chaser faced a harder task as each sound was new, completely separate and she had nothing to relate it to. Whereas children learn words within context that makes association and remembrance easier e.g. a cooker, refrigerator, microwave oven and kettle are found in the same place, meaning links of association are created.
One of the questions raised by the Rico study was that of what was the dog thinking as he located the item. Did the dog understand the cue “fetch” separately from its object, as a verb, as people do? Dr. Pilley took this into consideration by teaching Chaser three different verbs and the correct response to them: pawing, nosing and fetching an object. He then performed an experiment, asking Chaser to respond to each of the three cues on three different items. “That experiment demonstrates conclusively that Chaser understood that the verb had a meaning,” Dr. Pilley said.
Dr. Pilley is unsure as to how large a vocabulary Chaser could master. When she reached 1,000 items, he grew tired of teaching words and moved to teaching her to comprehend grammar. “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.”
Border collies are working dogs. They are reputed to be the most intelligent breed of dog, followed closely by Labrador retrievers and Poodles. A highly motivated and energetic dog, they are bred to herd sheep all day long with 100% precision without any fatigue. If these dogs are kept as companion animals, it is necessary that they are provided not only physical exercise but also require mental stimulation. If they are not kept occupied, like a bored child, they often start showing undesirable behaviours.
Dr. Pilley said that most border collies, with intensive training, could achieve such results. When he told Chaser’s breeder of her achievements, “he wasn’t surprised about the dog’s ability, just that I had had the patience to teach her,” Dr. Pilley said. One of Science’s advisers, Dr. Horowitz agreed: “It is not necessarily Chaser or Rico who is exceptional; it is the attention that is lavished on them,” she said.
‘Science’ journal rejected an article of the experiment as the experiment’s relevance to language is likely to be a matter of dispute. However an experiment of this calibre certainly has proved that a canine’s intelligence reach further depths than humans have anticipated previously.
Picture credit: Cass Sapir/Nova Science Now