Women use a higher-pitched voice when speaking to unfamiliar dogs

When women talk to dogs they do not know, they use a higher-pitched voice than they do when speaking to their own pets. The tone of voice and facial expressions people use also change depending on a dog’s size and the type of activity they are doing together. These results were recently published in the journal Animal Cognition.

To understand this research, it helps to look at the concept of prosody. Prosody refers to the rhythm, tone, and pitch of speech, as well as the facial expressions that accompany spoken words. Acoustic prosody includes vocal features like pitch range, while visual prosody relates to the facial movements a person makes while talking. People often use an exaggerated, high-pitched vocal style when speaking to babies, which helps capture a child’s attention and communicate emotion.

Research indicates that humans use a very similar style of communication when talking to their pet dogs. However, scientists are still working to understand exactly how the relationship between a person and an animal changes these speech patterns.

In human interactions, emotional attachment usually leads to more intense facial and vocal expressions. When adults speak to infants or romantic partners, they tend to use more exaggerated tones and facial movements than they do with strangers. This kind of communication strengthens social bonds and increases feelings of closeness.

A team of researchers set out to find if this holds true for dogs. They wanted to see if the bond between an owner and a pet creates the same intensely expressive communication style seen in close human relationships. Anna Gergely, a researcher at the Hungarian Research Center for Natural Sciences, led the investigation.

Gergely and her colleagues recruited 42 female dog owners to participate in the experiment. The researchers focused exclusively on women because previous studies indicate that female owners tend to be more talkative with their pets. Women also have a stronger tendency to use more exaggerated baby talk with dogs than men do.

Each participant was asked to interact with her own pet and with an unfamiliar dog of the exact same breed. By keeping the breed consistent, the researchers aimed to prevent natural breed preferences from affecting how the women reacted. The unfamiliar dogs were completely matched in breed to ensure the human participants would view both animals with a similar base level of affection.

The interactions were divided into three alternating scenarios, each lasting 30 seconds. In an attention-getting scenario, the women were instructed to call the dog and focus its attention on a toy or treat. In a task-solving scenario, the women played a simple game of hide and seek with the toy, encouraging the dog to guess which hand held the object.

The third scenario required the participants to recite a familiar Hungarian nursery rhyme to the dog twice. During all of these interactions, the dogs were held gently on a leash by a passive assistant who did not interact with the animals. The speaking participant sat on the floor so she was at eye level with the animal at all times, ensuring the camera had a clear view of her face.

While the women spoke to the dogs, the researchers recorded audio and video of the brief sessions. They fed the visual data into an automated facial analysis software program to track basic emotional indicators and overall facial muscle activation. This software evaluated the raw intensity of a person’s smile and overall facial arousal on a continuous mathematical scale.

They analyzed the sound recordings to track the average pitch of the participants’ voices. They also measured the pitch range, analyzing how much that pitch rose and fell throughout the interaction.

The results showed that familiarity altered only a single aspect of the human communication style. The women used a higher overall vocal pitch when speaking to a strange dog compared to their own pet. The researchers did not find any statistically significant differences in facial expressions based on whether the participant knew the dog or not.

This outcome runs counter to what happens in human communication, where familiarity usually increases the intensity of the speaker’s voice and expression. The research team noted that a high pitch acts as a universal friendly greeting signal across many animal species. High frequencies often work to grab the attention of animals while sounding non-threatening.

The researchers suspect that humans unconsciously raise their pitch to show friendly intentions to a strange animal. Because the dog has no prior experience with the human speaker, the speaker must rely on widely understood acoustic signals to show they mean no harm.

An owner and their own dog share a deep history, meaning they already understand each other’s specific relational signals. They do not need to rely on broadly recognized acoustic cues to establish a safe and friendly mood. Instead, the established bond allows the owner to use a more relaxed vocal pitch without worrying that the dog might misinterpret their intent.

As for why visual communication did not change based on familiarity, the researchers pointed to evolutionary differences between humans and canines. Human baseline expressions of surprise or extreme happiness involve wide, open eyes and exposed teeth. To a dog, these kinds of facial movements often signal aggression or a potential threat. Human speakers might subconsciously limit their facial expressions around all dogs to avoid sending aggressive cues, relying on their voice to carry emotional weight instead.

While familiarity only changed vocal pitch, the type of activity heavily influenced both voice and facial expressions. The simple attention-getting scenario produced the lowest overall pitch from the speakers. The researchers suspect that an excessively high pitch during this task might distract the dog, drawing the animal’s focus to the human face rather than the toy or treat.

The task-solving game prompted the widest range of vocal pitch from the women. Praising the dog’s successes and encouraging its overall efforts naturally led to a highly fluctuating, melodic voice. A wide pitch range appears to be an effective tool for communicating emotions and influencing a dog’s behavior during a structured game.

The nursery rhyme reading provoked the most intense visual responses from the speakers out of all the categories. The software detected the highest levels of facial muscle activation and the most intense happy facial expressions during this specific scenario.

The researchers suggest that the musical rhythm of a nursery rhyme combined with its association with human babies naturally triggers intense, child-directed facial expressions. People use highly animated facial cues when talking to infants, and reciting a nursery rhyme seems to automatically pull those exact expressions to the surface. Even though the subject is a dog, the context of the poem prompts human parental behavior.

The researchers evaluated dog body size as a final potential factor in human communication styles. They split the canine participants into two categories, separating those that weighed under 15 kilograms from those that weighed more. Fifteen kilograms is roughly equivalent to 33 pounds, creating an even split between small dogs and medium-to-large breeds.

The women used a wider pitch range and displayed more intense happy facial expressions toward the smaller dogs. The researchers attribute this physical change to the fact that small size often contributes to an animal’s perceived cuteness. A small dog might look more like a human infant, automatically prompting more baby-like communication from the speaker.

The research team acknowledged some limitations in their experimental design. The small dog group might have coincidentally contained more dogs with natural baby-like facial features, such as large eyes and small noses. This concentration of features could have driven the altered communication style, rather than the raw body weight of the animal alone.

Future studies should aim to separate a dog’s body size from specific facial features to isolate what exactly triggers changes in human speech. Researchers could also test different types of communicative tasks that do not involve reading from a piece of paper. Reading the nursery rhyme was the least spontaneous activity in the trial, which might have influenced how the participants behaved.

The study demonstrates that humans actively adjust how they speak to animals based on physical appearance and relationship status. People do not use a single, uniform method of talking to pets. Instead, they constantly adapt their pitch and expressions to match the immediate social and emotional needs of their canine partners.

The study, “The effect of familiarity and dog’s body size on female owners’ dog-directed communication,” was authored by Lőrinc András Filep, Édua Koós-Hutás, Fanni Hollay, József Topál, and Anna Gergely.