New study suggests dogs use a surprising method to understand human language

Humans have advanced linguistic abilities that may be unique among living creatures, but it seems dogs have learned some of our strategies.

In new research conducted in Hungary and published this week in the journal "Science," scientists found that dogs use the same strategy that infants use to distinguish words within a stream of speech: they rely on listening to consonant sounds (non-vowel sounds) to identify the end of one word and the beginning of another.

Attila Andics, a cognitive neuroscientist at Eötvös Loránd University in Budapest and author of the new study, explained: "This is what we call 'the consonant bias' — what we show here is evidence that dogs, unlike other mammals, do the same thing: they also process speech relying on a consonant bias."

To carry out the study, researchers brought 20 dogs and 20 humans into the lab and played them streams of meaningless syllables, some following patterns based on consonants, some on vowels, and others following no specific pattern. The scientists collected electroencephalogram (EEG) data to measure brain activity, according to The Washington Post.

Notably, some of the dogs had lived with families their whole lives, while others had spent time in shelters or on the streets during puppyhood, allowing researchers to test whether early exposure to speech is critical for dogs to acquire the ability to segment words by listening to consonants.

The researchers found that both dogs and humans showed increased brain activity when hearing the consonant-based patterns, including dogs that had been exposed to speech only later in life.

Andics said: "This study sheds new light on what we know about the evolution of language; it suggests that speech can shape the brains of animals that do not possess those complex, uniquely human language abilities."

An ability similar to humans' word-segmentation

The study adds to a growing body of research showing that dogs interact with language in ways that appear similar to how young children do.

In this context, Francis Subiaul, a cognitive scientist and associate professor at George Washington University (who was not involved in the study), said: "Infants face a unique challenge... They have to learn this highly complex signal. Think about speech: it contains a great deal of variability and noise — men's voices differ from women's, older voices differ from younger — yet we must get past all that noise and get to the essence: segmenting words and then understanding their meanings."

Subiaul noted that the fact dogs acquire this capacity reflects how attuned and in sync they are with us.

He said: "They listen and care about what is around them, and these experiences shape their brains in ways very similar to how the same experiences shape our children's brains."

A big question remains: is this the result of how dogs evolved through domestication over roughly 15,000 years, or was the ability latent in them from the start?

Subiaul added: "To answer that question you need a baseline control: wolves." He explained that researchers could conduct a study in which wolves are raised in speech-rich environments to see if they develop the same abilities, though he suspects they would not, given other research showing the huge role domestication played in creating harmony between dogs and humans.

Previous studies have found that interactions between dogs and humans lead to increased oxytocin levels in both, the bonding hormone that rises in parents and infants.

He said: "That can only be explained by domestication."

Subiaul has worked extensively with primates, and he believes that despite their intelligence, they would not achieve the same results as dogs in these tests.

He said: "Dogs seem more emotionally attuned to humans, and they are much more sensitive to human social cues; they respond more to eye gaze and to cues that direct attention (like pointing) compared with primates. We believe all of this is the result of domestication."

The new study was relatively limited in scope, and more research is needed to confirm the findings and fully understand how dogs developed this ability.

However, the researchers noted that the finding strengthens our understanding of how an unbreakable bond between humans and dogs emerged over thousands of years.

Amritha Malikargun, a postdoctoral researcher at Harvard (who did not take part in this study), said: "This highlights the long and important history that binds us; our shared experiences during the domestication of dogs have shaped their brains and our brains alike, which is evident across research on dog language and social behavior. I think this adds a new dimension to the story of dogs and their relationship with us."