Due to their long evolutionary history as domesticated animals, dogs have developed an ability to interpret human communication that far exceeds that of most other animals. And while some pet pooches may be more erudite than others, new research has revealed that the average dog is able to recognize 89 different words and phrases.
Presenting their findings in the journal Applied Animal Behaviour Science, the study authors explain how they set out to determine the extent of the canine vocabulary and to devise an inventory of the words and phrases to which dogs can respond. To do so, they asked 165 dog owners to assess their pets’ ability to recognize 172 different utterances.
These were chosen from an established vocabulary checklist that is commonly used to assess the language capacities of human infants, although the researchers also allowed participants to add some extra words and phrases that their pets had learned. Verbalizations were divided into seven categories, including names, commands, toys, food and drink, household items, outside places, and activities.
The most verbose dog in the study was able to recognize a total of 215 different expressions, while the least intelligent (but still very good dog) could only respond to 15. On average, dogs displayed a vocabulary stock that included 89 words and phrases, including 78 from the list provided by the researchers and 11 added by owners.
Perhaps unsurprisingly, the words that dogs were most likely to understand were their own names. Utterances such as “sit”, “come”, “down”, “good boy/girl”, “stay” and “no” were also recognized by more than 90 percent of pets.
In contrast, less than 10 percent were able to discern the meaning of difficult commands like “wipe your feet” or “whisper”, while very few dogs displayed an ability to recognize the names of other people or pets.
According to the authors, certain dog breeds were found to be more adept than others at responding to verbal cues. Purebred herding dogs and companion/toy dogs, for instance, had the largest vocabularies, while sports/gun dogs and terriers were the least wordy.
Further analysis revealed that dogs’ capacities to recognize speech were unaffected by their age or any of the characteristics of their owner. In addition to breed, the only factors that influenced their language skills were their professional working status and reported learning speed.
Professional canines such as military or police dogs, for instance, tended to recognize about 1.5 times as many words as those that lacked any career training. Based on this observation, the study authors suggest that “formal training might be required for dogs to learn to respond to many words.”
In addition to helping dog owners understand the limits of their pets’ vocabularies, the researchers say their findings could also “help predict early the potential of individual dogs for various professions.”