Say "doyouwannagoforawalk" out loud, and you'll notice there are no gaps between the words. Your brain adds them. Your dog's brain does something similar, relying on consonants to pick out word-like patterns in continuous speech.
That habit, called a consonant bias, was thought to be uniquely human. It hasn't even been found in primates, which are much more closely related to us. But a study published in Science found it in dogs. The result suggests that hearing speech day after day may be enough to reshape how a brain works.
“Taken together, these findings suggest that the brain's tuning to speech — and specifically the emergence of consonant bias — does not require a pre-wired brain and human-like language abilities,” said Attila Andics, co-author of the study, in a press release. “Instead, regular exposure to speech may be enough to change how the brain functions and to give rise to processing characteristics previously observed only in humans — even in a species evolutionarily distant from us.”
How Dogs’ Brains Find Patterns in Speech
Vowels tend to be louder than consonants, so they might seem like the easier sounds to follow. But in humans, consonants are more useful for finding words in a stream of speech.
Boglárka Morvai, a co-lead author of the study, and her colleagues wanted to know whether dogs, which hear people talk every day, might develop the same preference. They tested 20 people and 20 companion dogs.
Explore All OptionsThe researchers played them continuous streams of made-up syllables, with no pauses to mark where one “word” ended and the next began. In some streams, repeating consonant patterns formed three-syllable words while the vowels changed. In others, the vowels repeated and the consonants changed. A third stream had no repeating pattern at all.
The team used EEG to see whether the listeners’ brain activity kept pace with the repeating patterns.
Read More: From Mongolia to Madagascar, Dogs Form Remarkably Similar Bonds With Humans
Dog Brains Locked On to Consonant-Built Words
In both species, the brain synchronized more strongly with the rhythm of consonant-built words than with either vowel-based words or a stream with no pattern.
“This is the first evidence that a consonant bias can also emerge in the brain of a species other than humans,” said Kinga G. Tóth, the study's other co-lead author in the press release.
About 400 milliseconds after each word began, both human and dog brains showed a distinct change in electrical activity, but only for consonant-built words. That response is one sign their brains were finding where one word ended and the next began.
An earlier test using dogs' own names had not found a consonant bias. The authors say that looking for patterns in unfamiliar speech, rather than recognizing a familiar name, may be why it showed up here.
The bias also appeared in dogs that seem to have spent their first three months on the street or in a shelter, meaning that dogs may develop this preference without hearing lots of speech in early puppyhood.
Humans Still Hear Speech in Finer Detail
Human brains also tracked words built from vowel patterns, though less strongly than consonant-built ones. Dog brains did not show the same response to vowels, showing that people may be better at learning unexpected patterns in speech.
Both dogs’ and people’s brains followed the beat of the syllables. Only the people’s brains also followed the faster beat of the consonants and vowels within them.
The next time you ask your dog if it wants to go for a walk, you still can’t tell from this study exactly what it understands. But the sounds leading up to “walk” may be less of a jumble to its brain than you thought.
Read More: Dogs Can Have Positive Impacts on Our Mental and Physical Health — but Can They Help Us Live Longer?
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- This article references information from a study published in Science: Neural evidence that dogs segment the speech they hear with a humanlike consonant bias
