Our understanding of how dogs interpret the world continues to grow, revealing surprising insights. While it was long believed that their primary tool for recognition was smell, recent studies challenge this notion. A 2016 study published in PLoS ONE showed that dogs can discriminate human faces based solely on facial features, suggesting that the ability to recognize human faces may have been an adaptive advantage developed over thousands of years of domestication, facilitating communication and strengthening the bond between humans and dogs.
The authors of that study noted that this capacity for recognizing human faces is unique among canids and could be key to forming attachment bonds. It is possible that humans, unconsciously, selected dogs with brains predisposed to process human facial expressions, promoting smoother interaction. However, this is not the only way dogs seem to have a special predisposition for bonding with us.
A recent study from the Department of Ethology at Eötvös Loránd University (ELTE) in Hungary has taken a step further by demonstrating that dogs can recognize their caregivers solely through their voice. Published in the journal Animal Behaviour, this research is the first to provide evidence that dogs not only differentiate between familiar and unfamiliar voices but also identify a specific individual within a family group.
The experiment involved 31 dogs and their human families. In each case, three people who regularly lived with the dog were invited, ensuring that all three were familiar to the animal.
For the test, researchers recorded the voices of these three individuals reading a text. Then, the participants sat together in a room while the recordings of their voices were played through speakers positioned behind them. Throughout the process, the humans remained silent and still, so the dogs could only rely on the sound of the voice to identify who it belonged to.
The results were clear: dogs more frequently approached the person whose voice they had heard in the recording and also gazed longer at them. Accuracy was nearly absolute when the played voice belonged to the primary caregiver, suggesting that frequent interactions enhance this recognition ability.
While the exact mechanisms remain unclear, researchers analyzed potential demographic and acoustic variables to understand what influences this ability. According to Kinga Surányi, the study's lead author, "Dogs showed superior performance to chance for all family members, but their accuracy was even higher with their primary caregiver, likely due to the frequency of vocal interactions with that person."
The study also revealed that dogs not only distinguish between familiar and unfamiliar voices but recognize each family member individually.
This discovery has significant implications for understanding canine cognition and the evolutionary adaptations dogs have developed to coexist with humans. It also raises new questions about whether this ability is common among other mammals or specific to species that have evolved closely with humans.
"Dogs know much more about our voices than we imagine. They not only recognize if they have heard it before but also to whom that voice belongs," explained Anna Gábor, co-author of the study and researcher at the Communication Neuroethology Laboratory at ELTE. Future studies will seek to identify the specific acoustic mechanisms that enable this recognition and explore whether this behavior can be observed in other species.