It could be said that the sense of smell of dogs is their most precious weapon. To give several examples, dogs can recognize blood samples from people with cancer with an accuracy of almost 97% , according to a study carried out in 2021 by the American Society for Biochemistry and Molecular Biology. Dogs are also capable of identifying positive COVID-19 samples with 96% accuracy, according to a study by the University of Pennsylvania and published in the journal PLOS ONE . It is no coincidence, therefore, that their sense of smell exceeds 10,000 to 100,000 times that of humans. However, according to a study published February 10, 2022 in Animal Cognition , “man’s best friend” may recognize its owner more by voice than by smell .
The experiment was carried out with 28 dogs: 19 purebred and 9 mongrels and their owners. It took place in a laboratory room of the Department of Ethology of the Eötvös Loránd University, in Budapest. The animals’ task was to find their owners, based solely on their voice. The lab room had two doors, two opaque screens placed in two corners of the room, and a plastic wall placed between the screens. The purpose of the wall was to ensure that the dogs had to make a decision regarding their owner’s location immediately after leaving the starting point.
The dog’s owner and the researcher each hid behind a screen. Loudspeakers were also placed behind the screens. A second investigator entered the room with the dog. Now the dog had to identify its owner and approach the corresponding screen. The voice of the owner was played from his hiding place and the voice of a stranger from the other. Both voices read recipes in a neutral tone. The game had multiple rounds and the owner’s voice was paired with 14 different stranger voices, some more similar to the owner’s voice and some different. The starting point was 3.64m from the screens, given previous findings that dogs are barely able to find their hidden owners based on olfactory cues at 3m. Both the screens and the wall were blue. In all the tests, the sex of the owner and the stranger who was hiding behind the screen was the same, that is, if it was an owner, the stranger was a woman and vice versa.
In addition, to further ensure that the odors had nothing to do with identification, in the last two rounds of the test the researchers played the voice of the owner from the hiding place where the stranger was. The dogs continued to search for their owners’ voices, proof that they were not using their sense of smell in this task.
The result of the experiments was that the dogs found their owner in 82% of the cases . The researchers also wanted to know what helped the dogs choose voices.
“Overall, our results demonstrate that dogs can identify their owner based on vocal identity cues . We also reveal perceptually important acoustic parameters that dogs use to discriminate their owner’s voice from unfamiliar voices. This is the first study to reveal perceptually important markers of vocal identity that are used to discriminate between the voices of heterospecific individuals. Our results indicate that dogs use some of the acoustic cues that humans use to identify familiar speakers, but not all. Although dogs can detect fine changes in speech, their perceptual system may not be fully attuned to the identity diagnostic cues of the human voice.
Reference: Gábor, A., Kaszás, N., Faragó, T. et al. The acoustic bases of human voice identity processing in dogs. Anim Cogn (2022). https://doi.org/10.1007/s10071-022-01601-z
