The voice people use to address their dogs isn't just because of their big puppy eyes. Humans slow their own speech when talking to their dogs, and this slower tempo matches their pets' receptive abilities, allowing the dogs to better understand their commands, according to a study published October 1st in the open-access journal PLOS Biology by Eloïse Déaux of the University of Geneva in Switzerland and colleagues.
Dogs respond to human speech, even though they themselves cannot produce human sounds. To better understand how people and pups communicate, the scientists analyzed the vocal sounds of 30 dogs. They also analyzed the sounds of 27 humans across five languages speaking to other people, and 22 humans across those languages speaking to dogs. The scientists also used electroencephalography (EEG) to examine the brain responses to speech in humans and dogs.
Humans are much faster 'talkers' than dogs, the study showed, with a speech rate of about four syllables per second, while dogs bark, growl, woof, and whine at a rate of about two vocalizations per second. When talking to dogs, the humans slowed their speech to around three syllables per second. EEG signals of humans and canines showed that dogs' neural responses to speech are focused on delta rhythms, while human responses to speech are focused on faster theta rhythms. The authors suggest that humans and dogs have different vocal processing systems, and that slowing down our speech when speaking to pets may have ultimately helped us better connect with them.
The authors add, "What's further interesting, is that while dogs use slow rhythm to process speech and contrary to popular beliefs, they need both content and prosody to successfully comprehend it."
