Border collie Chaser's toy box became a long-running vocabulary experiment. Through years of structured play with psychologist John Pilley, she learned the proper names of 1,022 individual objects. When asked for a named toy, she could select it from a larger collection, demonstrating durable word-object associations rather than responding only to a familiar room or one repeated routine.

Chaser also learned that labels and actions could play different roles. A toy's name identified the object, while commands told her what to do with it. Combining a known action with different nouns tested whether she could apply an instruction across items instead of memorizing one inseparable phrase for each toy. That flexible pairing made the result more informative than a very large list of tricks.

The experiment did not show that Chaser possessed full human language, grammar, or open-ended conversation. It showed remarkable learned associations between spoken names and objects, plus the ability to combine those nouns with trained action commands. The precise accomplishment remains enormous. A dog, a patient training practice, and years of play built an organized vocabulary measured not in a handful of favorite objects, but in 1,022 distinct names.