When we hear the vocalizations of two different known animal species, humans are able to differentiate sounds based on who or what makes them. But the same thing happens with dogs who hear daily the voices of their owners and the barking of their peers?
A team of researchers from Eotvos Lorand University (ELTE, from BudapestHungary) asked this question and studied how dogs process different auditory cues. The results, published in the journal Royal Society Open Sciencereveal differences in pets’ responses to human and canine sounds for the first time.
Hungarian scientists did neurophysiological tests through non-invasive electroencephalograms (EEG) to 17 dogs that participated in the study. In this way, they were able to record the brain bioelectric activity under basal resting conditions and during several activations. So that they could understand neural processing of auditory information in dogs.
“We played various human and canine vocalizations to dogs that were lying down and alert while recording their brain activity using non-invasive electroencephalograms,” he explains. Anna Balintmember of Research Group on Comparative Ethology from the 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 to the subjects, unlike many other EEG paradigms used in animal studies,” reiterates the researcher.
Differences between species and between sounds
For the accomplishment of the study, the dogs were positive reinforcements (food awards), while scientists electrodes at specific points on the head and presented them with non-verbal human and canine vocalizations.
In the case of human sounds, the team made them hear laughs (positive) up yawns s cough (neutral). Canine sounds ranged from Barks game (positive) until sighs s sniff (neutral).
“The analysis of the recorded EEG signals showed that the dog’s brain processes the vocalizations of the two species differently. It is the first time that this has been detected in this way in dogs”, confirms Huba ElendPhD student at the Department of Ethology at ELTE.
Furthermore, this differentiation effect occurs very early, at 250 milliseconds, “so that the neural processing of human and canine sounds diverges already a quarter of a second after the onset 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 depending on the species. “Thus, we were able to show experimentally that the brain of dogs also responds to emotional content of the sounds they hear”, highlights Marta Gácsiprincipal investigator of the ELTE Comparative Ethology Research Group.
“The main merit of these discoveries is that, using this methodology, we can discover new details of the neural functions of our four-legged friends and how they process the acoustic signals of the world around them”, concluded Bálint.
Anna Balint et al. “Differences in event-related potentials of dogs in response to human and canine vocal stimuli; a non-invasive study” Royal Society Open Science