Despite their excellent hearing, dogs don’t care about differences between words that differ in only one sound of speech (e.g. dog versus dig). This emerges from a new study by Hungarian researchers from the research group Neuroethology of Communication MTA-ELTE ‘Lendület’ at the Eötvös Loránd University, Budapest (ELTE), which measures brain activity with non-invasive electroencephalography (EEG) in conscious dogs. This could be one reason why the number of words dogs learn to recognize tends to remain very low throughout their lives. The study was published in Royal Society Open Science. Photo credit: Vivien Reicher
According to a new study by Hungarian researchers from the MTA-ELTE research group “Lendület” for neuroethology of communication at Eötvös Loránd University, Budapest (ELTE), which measures brain activity with non-invasive electroencephalography (EEG) in conscious dogs. This could be one reason why the number of words dogs learn to recognize tends to remain very low throughout their lives. The study is published in Royal Society Open Science.
Dogs can distinguish between human speech sounds (e.g., “d”, “o”, and “g”), and there are similarities in the neuronal processing of words between dogs and humans. However, most dogs can only learn a few words during their lifetime, even if they live in a human family and are surrounded by human language. Magyari and her colleagues hypothesized that, despite the dog’s human-like hearing ability to analyze speech sounds, dogs may be less willing to consider all the differences between speech sounds when hearing words.
Electroencephalography (EEG) is a commonly used technique in human clinical trials and research studies, and has also been successfully used in dogs that are calm, asleep, or awake but trained. In this study, however, the researchers measured the EEG on conscious dogs without specific training. Photo credit: Elodie Ferrando
To test this idea, the researchers developed a method for the non-invasive measurement of electrical activity in the brain in conscious, untrained family dogs. Electroencephalography (EEG) is a commonly used technique in human clinical trials and research studies, and has also been used successfully in dogs that are calm, asleep, or awake but trained. In this study, however, the researchers measured the EEG on conscious dogs without specific training.
The researchers invited dogs and their owners to the laboratory. After the dog became familiar with the room and the experimenters, the experimenters asked the owner to sit on a mattress with her dog, as this would be a time to relax. Then the experimenters placed electrodes on the dog’s head and secured it with tape. When the electrodes were switched on, dogs heard taped instruction words they knew (e.g. “sit”), similar but nonsensical words (e.g. “sut”), and very different nonsensical words (e.g. “bep”) ).
“Electroencephalography is a sensitive method not only for brain activity, but also for muscle movements. So we had to make sure that dogs tense their muscles as little as possible during the measurement. We also wanted to include any type of family dog in our study, not just specially trained animals. We have therefore decided that we will not train our dog participants, but only ask them to relax. Of course, some of the dogs that came to the experiment couldn’t settle down and didn’t let us take the measurement. However, the drop-out rate from the study was similar to the drop-out rate in EEG studies with infants. It was also an exciting process for us to learn how to create a relaxed and safe atmosphere for the dogs and their owners in the laboratory, ”says lead author Lilla Magyari, postdoc at the Institute of Ethology at Eötvös Loránd University in Hungary.
Analysis of the recorded electrical brain activity showed that a dog’s brain clearly and quickly distinguished the familiar words from the very different nonsense words from 200 ms after the start of the words. This effect is in line with similar studies on humans, which show that the human brain reacts differently to meaningful and nonsensical words within a few hundred milliseconds. But the dog’s brain made no distinction between familiar words and those nonsense words that differed only in a single sound. This pattern is more similar to the results of experiments with infants around 14 months of age. Infants can efficiently process phonetic details of words, which is an important requirement for developing a large vocabulary between 14 and 20 months. However, younger infants do not process phonetic details of words in certain experimental and word-learning situations, even though infants are able to perceptually distinguish speech sounds within weeks of birth.
“Similar to infants, we speculate that the similarity of the brain activity of dogs for instruction words familiar to them and for similar nonsense words does not reflect restrictions of perception, but rather distortions of attention and processing. Dogs may not care about all the details of the sound of speech when hearing words. Further research could show whether this could be a reason why dogs are unable to acquire a large vocabulary, ”concludes Attila Andics, principal researcher of the MTA-ELTE research group for neuroethology of communication“ Lendület ”.
Reference: “Event-related potentials show a limited willingness to access phonetic details during word processing in dogs” by Lilla Magyari, Zsófia Huszár, Andrea Turzó and Attila Andics, December 9, 2020, Royal Society Open Science.
DOI: 10.1098 / rsos.200851
This study was published in December 9th Royal Society Open Science entitled “Event-related potentials show a restricted willingness to access phonetic details during word processing in dogs”, written by Lilla Magyari, Zsófia Huszár, Andrea Turzó and Attila Andics. This research was funded by the Hungarian Academy of Sciences (Lendület program), the National Bureau for Research, Development and Innovation and the Eötvös Loránd University (ELTE).
