In a new comparative fMRI study, Hungarian researchers at the Department of Ethology at Eötvös Loránd University have found that both dogs’ and humans’ brain show a general tuning to voicelikeness, that is, to sounds characterized by the complex acoustic properties of natural vocalizations. The paper that was published in Neuroimage suggests that a general sensitivity to voice-like stimuli is an ancient trait of the auditory system of the mammalian brain.
Voice sensitivity in a range of mammals has been proposed to be determined primarily by tuning to conspecific vocalizations. However, recent human findings indicate a role for a more general tuning to the voicelikeness of sounds. Additionally, vocal emotional valence has been linked to the same basic acoustic parameters across species: fundamental frequency (the frequency at which the vocal folds vibrate when voiced sounds are made; f0) and call length. To explore the role of voicelikeness in auditory processing, the authors used two categories of artificially generated emotional sounds: voice-like (similar to vocalisations) vs. sine-wave (simple periodical) sounds to investigate and compare the brain responses of dogs and humans in a non-invasive functional MRI experiment.
„We have found auditory cortical areas in both species that responded stronger to voice-like than to sine-wave stimuli, while there were no regions responding stronger to sine-wave sounds in either species.” – describes the results lead author Anna Bálint, postdoctoral researcher at the ELKH-ELTE Comparative Ethology Research Group. „Our results provide the first comparative evidence for a general voicelikeness-sensitivity in a non-primate mammal, since it has so far mostly been reported in primates, including humans.” – adds Bálint.
„In both species, we have found that the processing of voice-like and sine-wave sounds are modulated by f0 in opposite ways. These results reveal functional similarities between evolutionarily distant mammals for processing voicelikeness and its effect on processing basic acoustic cues of vocal emotions.” – says last author Attila Andics,, group leader of the MTA-ELTE ‘Lendület’ Neuroethology of Communication Research Group.
„Importantly, this indicates that the same auditory region’s sensitivity to the same basic acoustic parameter may be different depending on the acoustical structure of the processed sound, providing the first evidence of such differential sensitivity in a non-human mammal, the dog.” – adds last author Márta Gácsi, senior researcher of the ELKH-ELTE Comparative Ethology Research Group.
This research was published on the 9th December 2022 in Neuroimage, titled Dog and human neural sensitivity to voicelikeness: a comparative fMRI study