Many animals can pick out sounds in speech, but it turns out that dogs are better at it.
Dogs are very special when it comes to how interested they are in humans and how they interact with us. How much do they capture the nuances of our language? Do they see it as speech, instead of other sounds reaching their ears? Is it different from other sounds reaching their ears that they perceive it as speech? A new study suggests they are.
Four years ago, Laura Cuaya and Ral Hernndez-Pérez moved from Mexico to Hungary with their two border collies and one cat. They wondered if their canine companions had noticed that it was different to be surrounded by people speaking Hungarian instead of Spanish.
The evolution of speech perception in mammals, including dogs, is studied by Cuaya and Hernndez-Pérez in a research group at Etvs Lrand University in Hungary. More blood flowing to a specific region of the brain means more activity in the brain.
The group at the university showed that dogs use different neural pathways to recognize meaning than they do to sense emotional change. No one knew if the animals could distinguish between different sounds that were not a long string of words. No one knew if a dog could pick up on a person speaking a different language.
The border collies, Kun-Kun and Odn, were recruited by the researchers. The dogs were trained to lie still in an fMRI machine, but they were not familiar with either Spanish or Hungarian. The dogs heard passages from The Little Prince in both Spanish and Hungarian, thanks to a pair of noise-canceling headphones.
The researchers saw the same areas of the brain light up but with different activation patterns depending on whether the dogs were hearing the story in their native language or a new one.
The researchers tried to find out if the dogs were responding to specific characteristics. Is it possible that the animals were reacting to Hungarian words that put stress on the first syllable, or that they were reacting to basic differences in the sound of the two languages? They tested this by playing recordings in which the speech from the story had been garbled, resulting in gibberish that sounded like Hungarian or Spanish. The team can't say if this is proof that dogs can hear human speech, or if it's proof that dogs can hear speech in a meaningful way. The canines brain was not responding to the different tones of Spanish and Hungarian gibberish.
The study shows that the brain of a dog can distinguish between speech and speechlike sounds, and can even tell apart different human languages. Cuaya says that the dogs were able to hear a difference between human languages without being trained, which is the first time that a nonhuman brain can distinguish language. Holly Root-Gutteridge, an animal behavior scientist at the University of Lincoln in England, was not involved with the study.
A lot of people assume that dogs are only listening to the sound of a language, but they are actually picking up on our speech rhythms and how we sound when we speak a language.
The results have evolutionary implications. The evolutionarily speaking, dogs and humans are very different. There is a point in the evolution of humans and dogs when they were exposed to complex social environments. Even though there are differences in brain structure, both species have evolved different ways to detect changes in human speech.
Cuaya says that dogs are unique in their interest in humans. She says that dogs want to cooperate. They want to understand us.
