Women use higher pitched voices when talking to strange dogs than they do when talking to their own pets. The tone of the human’s voice and facial expressions also change depending on the size of the dog and the type of activity they do together. These results were recently published in the journal Animal Cognition.
To understand this research, it is helpful to understand the concept of prosody. Prosody refers to the rhythm, tone, and pitch of spoken language, as well as the facial expressions that accompany spoken words. Acoustic prosody involves audio features such as pitch range, while visual prosody involves the facial movements a person makes while speaking. When talking to babies, people often speak in an exaggerated, high-pitched voice, which attracts the child’s attention and helps convey emotions.
Research shows that humans use very similar communication styles when talking to pet dogs. But scientists are still working to understand exactly how the human-animal relationship changes these speech patterns.
In human interactions, emotional attachments usually result in more intense facial and vocal expressions. Adults tend to use more exaggerated tone and facial movements when speaking to young children or loved ones than when speaking to strangers. This type of communication strengthens social bonds and increases feelings of intimacy.
A team of researchers set out to find out if this also applies to dogs. They wanted to see if the bond between owners and pets produced the same highly expressive communication style seen in close human relationships. Anna Gergely, a researcher at the Hungarian Research Center for Natural Sciences, led the study.
Gergely and colleagues recruited 42 female dog owners to participate in the experiment. The researchers focused solely on women because past studies have shown that female owners tend to be more chatty with their pets. Women are also more likely to use exaggerated baby talk towards dogs than men.
Each participant was asked to interact with an unfamiliar dog of the exact same breed as their pet. By keeping breeds consistent, the researchers aimed to ensure that natural breed preferences did not influence women’s responses. The unfamiliar dog breeds were perfectly matched so that the human participants viewed both animals with similar basic levels of affection.
The interaction was divided into three alternating scenarios, each lasting 30 seconds. In the attention-getting scenario, the women were instructed to call the dog and focus its attention on a toy or treat. In the problem-solving scenario, the women played a simple game of hide and seek with toys and had the dog guess which hand was holding the object.
In the third scenario, participants had to recite a familiar Hungarian nursery rhyme to their dog twice. During all these interactions, the dog was gently kept on a leash by a passive assistant who did not interact with the animal. The speaking participant sat on the floor and was always at the animal’s eye level so that the camera could clearly see her face.
While the women talked to the dogs, the researchers recorded audio and video of the short sessions. They fed the visual data into an automated facial analysis software program that tracked basic emotional indicators and overall facial muscle activity. The software rated the raw intensity of a person’s smile and overall facial excitement on a continuous mathematical scale.
They analyzed the recordings to track the average pitch of the participants’ voices. We also measured the pitch range and analyzed how much the pitch rose and fell during the interaction.
They found that only one aspect of a person’s communication style changes with intimacy. The women used an overall higher pitch of voice when talking to strange dogs compared to their own pets. The researchers found no statistically significant differences in facial expressions based on whether participants knew the dog.
This result runs counter to what happens in human communication. In human communication, familiarity usually increases the intensity of a speaker’s voice and expressions. The researchers noted that high pitch acts as a universal friendly greeting signal in many animal species. High frequencies often work to get an animal’s attention while sounding non-threatening.
Researchers suspect that humans unconsciously raise their pitch to signal friendly intentions to strange animals. Because dogs have no experience with human talkers, talkers must rely on widely understood acoustic signals to demonstrate that they are harmless.
Owners and their dogs share a deep history, which means they already understand each other’s specific relationship signals. There is no need to rely on widely recognized acoustic cues to establish a safe and friendly atmosphere. Instead, the established bond allows the owner to use a more relaxed vocal pitch without worrying that the dog will misinterpret the owner’s intentions.
The researchers pointed to evolutionary differences between humans and dogs as to why visual communication did not change based on habituation. Basic human expressions of surprise or extreme happiness include wide-open eyes and exposed teeth. For dogs, this type of facial movement often indicates aggression or a potential threat. Human speakers may unconsciously limit their facial expressions to all dogs to avoid sending aggressive signals, relying instead on their voices to convey emotional weight.
Familiarity only changes the pitch of the voice, but the type of activity has a large effect on both voice and facial expressions. The simple attention-grabbing scenario resulted in the lowest overall pitch from the speakers. Researchers believe that speaking too loudly during this task may distract the dog, causing it to focus on the human face rather than the toy or treat.
In the problem-solving game, women’s voices had the widest pitch. Praising the dog’s successes and encouraging the dog’s overall efforts naturally resulted in a highly variable and melodic voice. A wide pitch range appears to be an effective tool for conveying emotion and influencing dog behavior during structured games.
Nursery rhyme readings evoked the strongest visual response from speakers of all categories. The software detected the highest levels of facial muscle activation and the most intense happy facial expressions during this particular scenario.
Researchers suggest that the musical rhythms of nursery rhymes and their association with human babies may naturally evoke intense, child-friendly facial expressions. When we talk to young children, we use very vivid facial cues, and when we recite a nursery rhyme, those exact expressions seem to automatically come to the surface. Although the subject is a dog, the context of the poem prompts the actions of human parents.
Researchers evaluated dog size as a final potential factor in human communication style. They divided canine participants into two categories: dogs weighing less than 15 kilograms and dogs weighing more than 15 kilograms. Fifteen kilograms equals approximately 33 pounds, split evenly between small dogs and medium-to-large dogs.
Women used a wider pitch range and showed more intense happy facial expressions toward small dogs. Researchers believe that this physical change is due to the fact that small size often contributes to the perception of cuteness in animals. Small dogs can resemble human infants, and speakers automatically encourage more baby-like communication.
The research team acknowledged some limitations in their experimental design. The small dog group may have coincidentally included more dogs with natural baby-like facial features, such as large eyes and small noses. This concentration of traits, rather than just the animals’ raw weights, may have caused changes in their communication styles.
Future research should aim to isolate body size and specific facial features in dogs to determine what exactly causes changes in human speech. Researchers can also test different types of communication tasks that don’t require reading paper. Reading nursery rhymes was the least spontaneous activity in the study, which may have influenced participants’ behavior.
This study shows that humans actively adjust the way they talk to animals based on appearance and relationship status. People do not use a single, uniform way of speaking to their pets. Instead, constantly adjust your pitch and expression to suit your canine partner’s immediate social and emotional needs.
The study, “The influence of familiarity and dog body size on female owners’ dog-initiated communication,” was authored by Lőrinc András Filep, Édua Koós-Hutás, Fanni Hollay, József Topál, and Anna Gergely.
