Do Dogs Have a Spoken Language?
Do Dogs Have a Spoken Language?
Dogs aren't known for speaking English, but recent research shows that they can understand language and are even able to pick up unfamiliar speech patterns. According to MRI scans, dogs can understand more when they are given information on both the left and right sides of their brains at the same time. This is because when a dog hears a scrambled version of a speech, the activity in their brains increases.
Brain scans show that dogs can pick up on unfamiliar speech patterns
In a recent study, scientists used fMRI scans to explore the brains of dogs, and found that they can detect speech patterns in a number of different languages. Researchers had eighteen dogs in the study, ranging from three to eleven years old, and included one labradoodle, six border collies, and five golden retrievers. They tested the dogs' response to a range of natural and scrambled speech, exposing them to an audio excerpt from Antoine de Saint-Exupery's The Little Prince in Hungarian and Spanish.
Dogs are good pets, and they do well in a human-dominated environment. But they have been retooling their speech detection skills over millennia, allowing them to pick up on different human languages. This is the first time that scientists have shown that a non-human species has the ability to distinguish between two human languages.
To determine whether dogs can detect speech patterns, researchers looked at the brain's response to natural and scrambled speech. In a searchlight MVPA, they scanned the dogs' brains and identified distinct activity patterns when they heard Natural speech in an unfamiliar language, as compared to Scrambled speech in a familiar language.
For the study, Cuaya and her colleagues gathered 18 family dogs, between the ages of three and 11, and compared brain activity when the animals were exposed to the same sounds in both Hungarian and Spanish. They played recordings in the dog's native language, and also a voice recording of the owner's voice.
These brain scans showed that dogs can detect speech patterns in a number of languages, indicating that their speech detection may be more than simply a function of sensitivity to the naturalness of the sound. Their responses were more pronounced in older dogs, suggesting that the neural capacity to detect speech is based on a sensitivity to the language-specific regularities of speech rather than a preference for detecting speech.
One possible explanation is that dogs use implicit knowledge to build representations of a language. However, these may be limited to a particular language, and there is still plenty of room for further experiments to determine if dogs have areas of the brain dedicated to detecting speech in general, or if they are more sensitive to the temporal and naturalness of a particular language.
Several of the regions studied, including the mid suprasylvian gyri and Heschl's gyrus, are involved in pre-linguistic processing of speech. They were used to process spectral voice cues and emotional intonation, and are thought to be part of the same auditory network. When dogs are exposed to language, the secondary auditory cortex lights up, which is associated with the deciphering of meaning. Similarly, a PG (precruciate gyrus) and a rSSG (rostral suprasylvian gyrus) are found to be active when humans read a text.
Brain activity increases when a dog hears scrambled speech
In an effort to understand the brain's ability to detect speech, researchers exposed dogs to natural and unfamiliar speech. They then scanned the brains of the dogs using functional magnetic resonance imaging. The study found that their brains performed complex statistical calculations and could detect speech in different forms.
Researchers from the Eotvos Lorand University in Hungary studied the effects of two kinds of sound on a dog's brain. The first type of sound was natural, and the second was scrambled. Searchlight MVPA was used to compare activity patterns for each kind of speech. Naturalness was rated on a seven-point Likert scale.
The results show that the neural capacity to detect speech in a dog is based on sensitivity to the "naturalness" of the sound. Differential activity patterns in the primary and secondary auditory cortical regions suggest that the dog has the ability to differentiate between natural and scrambled speech. These findings are an important step in understanding the neural processing of speech in non-human species.
The researchers observed the responses of family dogs and dogs that had been trained to listen to a specific language. Dogs that had been exposed to Spanish and Hungarian showed differences in their responses to both kinds of language. For example, the brains of Kun-kun, a six-month-old dog that had been trained to listen to both languages, responded differently to paired syllables than to random words. Aside from that, Kun-kun had also been trained to lay motionless on a MRI machine to allow for a more detailed analysis.
Using fMRI, scientists discovered that the lexical adaptation was age-modulated in the near-primary auditory region. This suggests that the right hemisphere has a bias toward lexical adaptation. Moreover, the study indicates that the lexical adaptation is independent of prosody.
The study also found that older and longer-headed dogs had greater difference in response to both languages. Older dogs were more able to discern between familiar and unfamiliar languages. Interestingly, both of the languages in the study were considered to be "familiar," but the differences were not great. However, this study was the first to demonstrate that a non-human species can distinguish between familiar and unfamiliar languages.
The research team believes that the dog's capacity to detect speech is a trace of word learning, as it is not a fixed set of stimuli, but a process of statistical computations. Dogs are believed to use implicit knowledge to build representations for a language, but researchers still need to explore the specifics of how dogs learn to identify individual words.
It's a good thing that researchers weren't looking for a nirvana. The searchlight MVPA analysis revealed distinct neural representations for different types of speech. One of the main reasons why this is interesting is because dogs' brains have a complex computational mechanism that supports the recognition of sounds.
MRI scans show that dogs can understand better when both sides of the brain are in play
MRI scans of canine brains have revealed that dogs can understand better when both sides of their brain are working at the same time. These findings may be especially valuable in cases where dogs are living in a foreign country where the native language is unfamiliar. Despite this fact, scientists have been unable to determine whether or not dogs can recognize a specific language.
Researchers from Eotvos Lorand University in Budapest, Hungary, used MRI scans to investigate how the dog's brain responds to the sounds of different languages. They studied 18 adult family dogs with a range of ages. The dogs' brains were scanned while they were listening to recordings of a variety of human voices, including a reading of "The Little Prince" in Spanish.
Dogs' brains showed a greater response to certain types of human voices than to other kinds of noises. This is because canine brains are not very good at distinguishing between speech and non-speech. On the other hand, they did respond to sounds that were emotionally charged. Specifically, when the researchers played random words in a sweet tone, dogs' brains would activate.
Another study, conducted by Laura Cuaya, a postdoctoral researcher at the Eotvos Lorand University in Hungary, was based on the hypothesis that dogs can recognize the sounds of a language, even if it is not their native tongue. Researchers studied 18 pet dogs in an MRI scanner. The dogs were trained to stay still during the scans. In addition, the dogs had to pick the correct toy on command. Afterwards, the scientists compared the results of the dogs' brains with the brains of 22 human volunteers.
In addition to revealing that dogs can differentiate between two languages, the study also showed that the dog's brain was sensitive to both the naturalness and the scrambled nature of a word. This is a first-of-its-kind finding for non-human animals, according to the researchers. Previously, the only way to study the differences between human and non-human animals was to study humans' brains. But it is difficult to compare results from different species because of the lack of reporting standards.
For example, dogs have less surface area, which means they do not have the same amount of neural infrastructure as a human. Moreover, they have a smaller frontal lobe, which consists of only ten percent of the canine's brain. That leaves dogs with a lower EQ, or electroencephalogram. A higher EQ may help them pick up on the meaning of a word, but it could lead to confusion if they are exposed to other kinds of sounds.
In addition to the MRI, Cuaya and her colleagues also performed fMRI. During the fMRI, the researchers monitored the dogs' brain activity while they were speaking. Besides comparing the dogs' brains with the humans', they also played recordings to the dogs during the fMRI scans.