A team of researchers has found that dogs pay attention to both the words and tone when listening to human speech. Like humans, they process word meanings in the brain’s left hemisphere and intonation in the right hemisphere. The details are in a paper just published in the journal Science.
Researchers analyzed the brain activity of thirteen dogs. The dogs had been trained to lie down in a functional magnetic resonance imaging scanner. The research team recorded brain scans as the dogs listened to their trainer’s speech. The dogs heard their trainers say praise words in a positive tone, praise words in a neutral tone, and meaningless words (conjunction words that the dogs wouldn’t associate with anything) in both tones.
The team found that the dogs used their left brain hemisphere when processing the meaning of words. The hemisphere was activated when the dogs heard meaningful words, regardless of tone, but not when they heard the meaningless conjunction words. When processing intonation, the dogs favored the right brain hemisphere. The team also noticed that the reward center, a part of the brain associated with pleasure, only activated when the dogs heard praise words in a positive, praising tone. In other words, the dogs combined meaning and intonation when processing their trainer’s speech.
The findings are helping researchers understand how dogs process and understand human speech. Previously, it was believed that dogs had very simple speech processing since they are not able to speak. This new study proves otherwise, showing that dogs use both brain hemispheres to determine what a phrase actually means. The dogs considered both meaning and intonation when processing their trainer’s speech. The authors speculate that this is because most dogs are raised in an environment where they constantly hear human language. The ability to understand the words used around them would enhance the dogs’ ability to communicate and cooperate with their families.
Andics et al. Neural mechanisms for lexical processing in dogs. Science (2016).