Voice and speech perception across mammals: a comparative study of humans, dogs and pigs
Vocalizations of any mammal carry prominent cues about the inner states and identity of the vocalizer. Voice is also a prevalent channel for humans’ recently emerged communication system, speech. Recent evidence suggests that certain human auditory brain specializations and mechanisms, relevant for voice and speech perception, reflect abrupt shifts in human capacities compared to other primates.
Main questions
Do these brain specializations for voice and speech perception reflect human-specific predispositions and are thus human-unique, or are they the consequence of rapid evolutionary adaptations or developmental accommodations of the ancient voice perception system to recent demands imposed by the presence of speech? We hypothesize that in general voice perception mechanisms are conserved across mammals, and provide a neuronal niche in which specializations for human voice and speech perception may arise also in non-humans.
The comparative neuroscientific approach
The case of companion animals provides an unparalleled model system to study the possible evolutionary and experiential effects of the presence of speech on the mammalian voice perception system. Dogs and pigs are phylogenetically distant, highly vocal species that live, when kept as companions, with humans. Our research combines ethology and brain imaging (EEG/fMRI/HD-DOT) to compare voice and speech processing in humans, dogs, and pigs. Specifically, (1) we seek evidence for selective processing of conspecific voices, human voice, and speech. (2) Our research explores the mechanisms and specific sensitivities for inner state coding, voice identity recognition, and vocalizer normalization, from con- and heterospecific voices. (3) We test how sensitivities to human voice and speech emerge across dog breed types, in neonate dogs, pigs, wolves and wild boars, and in input-manipulated developing dogs. Revealing how adaptation to the human social niche shapes domestic mammals’ voice perception, this project provides new insights on how speech shaped human voice perception.
Funding:
