Dogs can tell if a person is familiar: the key is in the human voice

A new research published in Animal Behavior has provided the first evidence that dogs are capable of recognizing humans at an individual level based on voice.

“Previous studies have shown that dogs are sensitive to certain acoustic cues in the human voice, can recognize the sex of the speaker and distinguish between familiar and unfamiliar voices. Whether dogs are able to recognize humans at an individual level based on voice had not been demonstrated before this experiment,” explains Kinga Surányi, doctoral student at the Department of Ethology at ELTE (Eötvös Loránd University) in a statement. Hungary.

LOOK: Kia E-Ground, an experience center in the middle of the world where automotive electrification and environmental sustainability are promoted

In individual-level recognition, animals can identify certain individuals even within the same social category (e.g., siblings), which may be crucial for their communication. However, distinguishing between equally familiar voices presents a difficult task. Demonstrating this ability in animals is challenging, especially when they hear voices from another species (e.g., humans).

It must be demonstrated that the animal can differentiate the voices of other individuals, while ensuring that all vocalizers are equally familiar with it. Although this ability appears to be beneficial for vocal species, individual-level voice-based recognition of humans has so far only been demonstrated in rhesus macaques and horses.

To find out whether dogs are capable of recognizing humans on an individual level, researchers from the ELTE Department of Ethology invited three people from the same dog-owning family to participate in a special experiment. Each dog attended with its three owners, all equally familiar to the dog.

The owners’ voices were recorded, then they sat next to each other and speakers were placed behind them. The researchers played one of the three voices and the dog had to approach the person to whom the voice belonged. The 31 participating dogs did this 18 times.

While the pre-recorded speech played over the speakers, the owners did not speak or make any gestures, so the dogs had to choose based solely on the voice they heard. Using a questionnaire and acoustic analysis of the owners’ voices, the researchers investigated possible demographic and acoustic variables that could influence the dogs’ voice recognition abilities.

“The dogs performed well: they chose more often and looked longer at the person whose voice they heard. The dogs’ performance was above chance for all family members, indicating that they could recognize all of them based on voice. Additionally, the dogs’ performance was better when they heard their primary owner’s voice. This could be because the dogs had more frequent vocal interactions with the main owner and were more likely to need to react to his voice,” adds Anna Gábor, postdoctoral researcher at the Laboratory of Communication Neuroethology.

This study provides the first evidence of individual-level recognition of humans in dogs. “Dogs can discriminate between familiar human voices and match the voices to those of the corresponding person. This ability also seems to be beneficial for communication between different species,” says Surányi.

“The study shows that dogs know a lot about human voices: not only whether they have heard them before or not, but also who that voice belongs to. Future research should clarify whether this is a general ability among mammals or the result of specific evolutionary adaptations in certain species for which humans are especially important,” explains Gábor.