Dogs pick out words in continuous speech more easily when consonants define them than when vowels do. Until now, this consonant bias had only been seen in humans. The results appear in the journal Science.
The study comes from the Neuroethology of Communication Lab at the Department of Ethology at ELTE University in Budapest. It involved 20 dogs and 20 people, whose brain activity the team recorded with scalp electrodes (EEG).
"Consonants usually form the skeleton of words," says Attila Andics, the cognitive neuroscientist who heads the study.
The experiment
Everyone listened to an unbroken stream of syllables that alternated consonants and vowels. One stream was built from words defined by consonants, another from words defined by vowels, and a third had no pattern at all.
In both dogs and humans, brain activity synchronized best with the rhythm of the consonant-based words. About 400 milliseconds after such a word began, a distinct change appeared in the signal, and only for that stream.
Dogs that spent their first three months in shelters or on the street showed a bias as strong as family pets.
Where they differ
Dogs did not detect the vowel-defined words and treated the syllable as the smallest unit. Humans break speech down into individual sounds.
"This provides further evidence that consonant bias does not require prewired language-processing mechanisms," says Kinga G. Tóth, a psychologist and co-first author. Andics says regular exposure to speech may be enough to shape how the brain handles it.
