Lead author Nicolas Mathevon, from the University of Lyon at Saint-Étienne in France, said pet-directed speech, or “puppy-talk”, is extremely common and strikingly similar to human infant-directed speech, or “baby-talk”, employing a higher vocal pitch and slower tempo to engage an infant’s attention.
The authors recorded adult participants speaking in front of of 30 pictures of puppies (younger than one year), 30 adult dogs (1 to 8 years old) and 30 old dogs (more than 8 years old) and analysed the quality of their speech. Each of the 30 female participants spoke the same phrases in puppy-talk and normal speech.
Scientists then performed playback experiments to assess dogs’ reaction to dog-directed speech compared with normal speech.
They found human speakers used dog-directed speech with dogs of all ages and the acoustic structure was mostly independent of dog age, except for sound pitch, which was relatively higher when communicating with puppies.
Playback demonstrated, in the absence of other non-auditory cues, puppies were highly reactive to dog-directed speech and pitch was a key factor modulating their behaviour, suggesting this speech register has a functional value in young dogs.
Conversely, older dogs did not react differentially to dog-directed speech compared with normal speech. The fact speakers continue to use dog-directed with older dogs suggests it may mainly be a spontaneous attempt to facilitate interactions with non-verbal listeners.