Dogs have the ability to discern the vocabulary and intonation of human speech, using brain regions similar to humans, a new study reports. Humans understand speech through both vocabulary and intonation. The researchers examined whether dogs also understand both mechanisms. Dogs were exposed to recordings of their trainers' voices, and these spoke using multiple combinations of words and intonation, in both laudatory and neutral ways.
Researchers used MRI to analyze the dogs' brain activity after the animals had listened to each combination. The results showed that regardless of intonation, dogs process vocabulary, they recognize each word as distinct, and they do so in a way similar to humans, using the left hemisphere.
The researchers also found that, like humans, dogs process intonation separately from vocabulary, in auditory regions in the right hemisphere. Finally, the team found that just like humans, dogs rely on both word meaning and intonation when processing the reward's value of utterances. Thus, dogs seem to understand human words as well as intonation.