Just as people recognize the song of a bird or the bark of a dog, the latter not only differentiate canine vocalizations from humans, but also recognize the emotional content of each sound. This is revealed by a study that analyzed the neural processing of their auditory information with non-invasive electroencephalograms.
When we listen to the vocalizations of two different known animal species, we humans are able to differentiate the sounds based on who or what is doing it. But does the same thing happen with dogs who hear the voices of their owners and the barking of their peers on a daily basis?
A team of researchers from Eötvös Loránd University (ELTE, Budapest, Hungary) asked this question and studied how dogs process different auditory signals. The results, published in the journal Royal Society Open Sciencereveal for the first time differences in pet responses to human and canine sounds.
Hungarian scientists performed non-invasive electroencephalogram (EEG) neurophysiological examinations on 17 dogs that participated in the study. In this way, they were able to record brain bioelectric activity under basal resting conditions and during various activations. Thus, they were able to understand the neural processing of auditory information in dogs.
“We played various human and canine vocalizations to lying, alert dogs while we recorded their brain activity using noninvasive electroencephalograms.says Anna Bálint, a member of the comparative ethology research group ELTE and first author of the research.
“This new EEG methodology was recently developed by Hungarian researchers based on human procedures and is completely painless for subjects, unlike many other EEG paradigms used in animal studies.», reiterates the researcher.
Differences between species and between sounds
To conduct the study, the dogs received positive reinforcement (food rewards), while the scientists applied electrodes to specific points on their heads and presented them with non-verbal human and canine vocalizations.
In the case of human sounds, the team had them listen to everything from (positive) laughter to (neutral) yawns and coughs. Canine sounds ranged from playful barks (positive) to gasps and sniffles (neutral).
“Analysis of the recorded EEG signals showed that the dog’s brain processes the vocalizations of the two species differently. This is the first time it has been detected in this way in dogs.confirms Huba Eleőd, a doctoral student in the Department of Ethology at ELTE.
Moreover, this differentiation effect occurs very early, at 250 milliseconds, “thus the neural processing of human and canine sounds diverges already a quarter of a second after the start of the sound“, continues the scientist.
Another important finding observed in the brain responses of dogs is that they are able to differentiate between positive and neutral vocalizations according to species. “We were thus able to show experimentally that the brain of dogs also reacts to the emotional content of the sounds they hear.“, emphasizes Márta Gácsi, principal researcher of the ELTE Comparative Ethology Research Group.
“The main merit of these findings is that by using this methodology, we can learn new details about the neural functions of our four-legged friends and how they process acoustic signals from the world around them.Balint concluded.
Anna Balint et al. “Differences in event-related potentials of dogs in response to human and canine vocal stimuli; a non-invasive study”