If you have a dog, you're likely in the habit of asking them, "Who's a good boy?" in a really high-pitched and affectionate tone of voice — sometimes to the amusement of those around you.
Pet owners do this instinctively because they feel just as attached to their pets as they may to their infant. But does this sort of "baby talk" do anything for the dog?
Researchers Alex Benjamin and Katie Slocombe, at the University of York in the United Kingdom, set out to investigate if so-called dog-speak improves bonding between pets and humans, and specifically, whether it is useful for the dogs.
Slocombe explains the motivation behind the research, saying, "A special speech register, known as infant-directed speech, is thought to aid language acquisition and improve the way a human baby bonds with an adult."
"This form of speech," she adds, "is known to share some similarities with the way in which humans talk to their pet dogs, known as dog-directed speech."
"This high-pitched rhythmic speech is common in human interactions with dogs in Western cultures, but there isn't a great deal known about whether it benefits a dog in the same way that it does a baby."
"We wanted to look at this question and see whether social bonding between animals and humans was influenced by the type and content of the communication," Slocombe says.
Their findings were published in the journal Animal Cognition.
Proof that dogs prefer dog-speak
For the study, the researchers designed two experiments in which humans interacted with dogs. In the first, the researchers tested adult-directed speech versus dog-directed speech.
The latter was tailored for dogs both in terms of content (that is, the dogs were told things such as "You're a good dog" and "Shall we go for a walk?") and in prosody (that is, in stress patterns and intonation).
By contrast, adult-directed speech contained sentences such as "I went to the cinema last night," which were spoken in a "normal" tone of voice.
The dogs' attention spans were measured during the two speech types, and after hearing them, the dogs were invited to choose which speaker they wanted to interact with.
This first experiment revealed that the dogs strongly preferred humans who had addressed them using dog-directed speech. However, there was the possibility that it was simply the emotional tone that appealed to the dogs and that the content didn't have anything to do with their preference.
'Dogs need to hear dog-relevant words'
So, in the second experiment, "the content from experiment one was reproduced but with reversed prosody such that the dog-related content was spoken with the prosody of [adult-directed speech] and vice versa."
Benjamin — who is a Ph.D. candidate in the Department of Psychology at the University of York — summarizes the findings.
"We found that adult dogs were more likely to want to interact and spend time with the speaker that used dog-directed speech with dog-related content, than they did those that used adult-directed speech with no dog-related content."
"When we mixed-up the two types of speech and content," he adds, "the dogs showed no preference for one speaker over the other."
"This suggests that adult dogs need to hear dog-relevant words spoken in a high-pitched emotional voice in order to find it relevant."
"We hope this research will be useful for pet owners interacting with their dogs, and also for veterinary professionals and rescue workers," Benjamin adds.