The learning of vocabulary does not seem to be a distinctive human capacity derived from the appearance of language, but rather an ancestral function that can be trained to learn to relate arbitrary sequences of sounds with meanings . Words are the basic building blocks of human languages , and they are hardly found in other types of non-human vocal communications. Intonation is another of the tools to send information in speech. For example, praise is usually higher in pitch, with higher notes and variations in rhythm. People understand speech through these two elements: vocabulary and intonation .
Biologist Attila Andics, a learning expert at the University of Budapest, has explored in an experiment the mechanisms dogs use to communicate and understand sounds . To do this, they played several dogs with audio recordings with the voices of their trainers as they spoke to them using multiple combinations of words and intonations, and mixing praiseworthy messages with other neutrals. For example, they spoke flattering words with enthusiastic intonation, flattering words with neutral intonation, neutral words with praising intonation, and neutral words with neutral intonation.
The researchers involved in the experiment used MRI to analyze the dogs’ brain activity as they listened to all possible combinations. The results showed that, regardless of intonation, the animals were able to process vocabulary and recognize each word as different from the others in a similar way to people, using the left hemisphere of the brain .
They also found that, like humans, dogs processed intonation separately from vocabulary in auditory regions of the right hemisphere of the brain. Finally, and also like us, they relied on both tools, the meaning of the words and the intonation, when they processed the praiseworthy message of the sentences. So it seems that our best friends seem to understand both human words and the tone in which they are spoken. For Andics and his colleagues it is likely that the mechanisms of natural selection during the domestication of dogs supported the appearance of brain structures that allow them to understand. Of course, humans are still unique in terms of the ability to invent words.
Photo caption: dogs trained next to the MRI machine
Credit: Enik Kubinyi
