NEWS AND OPINION: Adult human speak more slowly to babies, dogs and cats. I’m referring here to a recently published research paper on the Plos One website (PLOS BIOLOGY), which has been reported in The Times newspaper. The core conclusion is one that we readily recognise and find unsurprising namely that we speak more slowly to our dog companions. This was a study about dogs and the dog-human relationship but I would argue that it applies equally to cats and the cat-human relationship as well.
Update October 3, 2024 from a letter to the editor of The Times newspaper: Dear Sir, while there is much to admire in the Pasteur Institute study anyone who has ever owned a Labrador knows that you can talk as fast as you like when food is in the offing. Alan Carmichael, Nairobi.
It’s argued that dogs have indirectly trained us to speak more slowly to them. An automatic consequence of the dog or cat and human relationship is that our dog and cat companions train us informally to behave in a way which enables us to better communicate with them. We accept this with open arms because we want to communicate with them and we learn that if we speak more slowly, they better understand things.
The leading member of the research team, Dr. Eloise Déaux, from the University of Geneva, argues that when communicating with dogs we speak at a rate which is in between a dog’s natural vocalisation rhythms and our own rhythms. It’s a compromise.
And we do this “dog-directed speech” to be better understood. Unhurried human speech directed at dogs (and once again I would argue cats) are more in sync with that part of the dog’s brain dealing with speech.
The research was overseen by Professor Anne-Lise Giraud, head of the Hearing Institute at the Pasteur Institute in Paris. They investigated the speeds at which humans and dogs vocalise. They concluded that humans vocalise at a faster rate than dogs in making between four and seven different sounds a second whereas dogs produced only two on average per second.
And then they analysed the speech of people when they talk to dogs and found that they tended to slow down.
The research team placed electrodes on the heads of 12 dogs. The dogs heard recordings of their owners delivering instructions such as “sit” and “come”. They were played at different speeds.
They discovered that the dogs were more likely to obey commands when they were spoken slowly. And they also found that the words themselves were important not only the intonation of the words.
The information gained in the research showed them that the dogs were relying on slower brainwaves (delta waves) to make sense of the human vocal instructions.
Delta waves involve groups of brain cells firing between one and three times per second. This matches the rate at which the dogs made sounds when they bark or express themselves vocally in other ways.
It’s believed the findings help to shed some light on the human-dog relationship. Once again, I would argue that these findings are relevant to the cat-human relationship as well but historically researchers work with dogs rather than cats for obvious reasons namely that it is more convenient and more efficient.
Eloise Deaux said that “Our dogs do process speech, but in a way that is constrained by their own, slower vocalisation capacities.”
And, as mentioned, slower speech is also used when adults talk to infants which indicates that humans use the same tactic to be better understood. It’s believed that humans first learned to speak more slowly to dogs when they first became domesticated around 20,000 to 30,000 years ago.
“To foster good verbal communication with dogs, we should be mindful of using slow speech to match their ability to parse it.”
To quote from the discussion section of their openly published report on the Internet:
“Overall, these results reveal that dogs’ auditory and vocal systems have aligned on a single temporal processing window that differs from that of humans, and which remains predominant even when dogs process and appropriately respond to human speech. In parallel, we show that humans who speak to their dogs adopt a speech rate that differs from adult-directed speech and more closely aligns with the dog’s neural delta oscillatory capacity. These data are consistent with the hypothesis that in the history of the dog-human relationship, the neural constraints of the dogs’ reception system may have limited this heterospecific [belonging to a different species or group] communication to a temporal [relating to time] structure falling midway between the natural speech rate and a slower rate that would perfectly match the dog’s analysis capacity. However, future research on different animal-directed speech registers particularly as it pertains to their temporal characterisation is needed before we can fully establish the extent to which humans are sensitive to their target’s perceptual constraints and whether the dog–human relationship is as special as it may appear.
Link to the study: PDF file: Dog–human vocal interactions match dogs’ sensory-motor tuning
