In this episode, we explore how stress in dogs reflects the stress of their human companions—but only for some breeds. Drawing on two studies by Lina Roth and colleagues, we examine how long-term stress synchronisation between dogs and owners is shaped by breed history, owner personality, and the perceived burden of dog ownership. One study found that herding dogs often mirror their owners' stress physiology, while another found that ancient and solitary hunting breeds do not show this same synchrony. Together, these findings offer a nuanced picture of emotional contagion and cooperation in the human–dog relationship.
Key topics
Long-term stress synchronisation in dog–owner dyads
Differences between herding, ancient, and solitary hunting breeds
Role of owner personality in shaping canine stress
The impact of perceived costs in the human–dog relationship
Seasonal variation in dog stress levels
Implications for welfare and breed-specific understanding
Long-read article
Overview of the studies
This article draws from two empirical studies published in Scientific Reports by research teams led by Lina Roth and Per Jensen, based at Linköping University in Sweden. Together, these studies investigate whether dogs reflect the long-term stress of their owners and under what conditions such physiological synchronisation occurs.
The first study (Sundman et al., 2019) focused on herding breeds and was the first to demonstrate interspecies synchronisation of long-term cortisol levels—specifically, hair cortisol concentrations (HCC)—between humans and dogs. The second study (Höglin et al., 2021) expanded the inquiry to ancient and solitary hunting breeds, exploring whether similar stress alignment could be observed in breeds with different evolutionary histories and behavioural profiles.
The core hypothesis tested across both studies is whether dogs mirror their owners' chronic stress—and if so, what variables influence this mirroring: breed, personality, sex, lifestyle, or the quality of the human–dog relationship.
Dogs as mirrors: Synchronised stress in herding breeds
In the 2019 study, researchers recruited 58 dog–owner dyads, including Shetland Sheepdogs and Border Collies. Hair samples were collected from both dogs and their owners during the summer and winter to track cortisol levels over time. The primary measure—hair cortisol concentration (HCC)—offers a retrospective view of chronic stress over weeks or months, unlike saliva or blood which capture acute responses.
Key finding: A strong, statistically significant correlation was found between dog and owner HCC across both seasons. The synchrony persisted even after accounting for lifestyle differences (e.g., pet vs. competition dogs), suggesting a robust interspecies alignment.
Interestingly, the direction of influence appeared asymmetrical. Owner personality traits (measured via the Big Five Inventory) were significantly associated with dog stress levels, while the reverse was not true. For instance:
Higher owner neuroticism predicted lower dog HCC.
Higher conscientiousness and openness predicted higher dog HCC—but only in winter.
Dog personality traits (assessed via the Dog Personality Questionnaire) and activity levels did not significantly affect cortisol levels.
This implies that dogs do not merely reflect shared environments or routines—they appear to internalise aspects of their owners' emotional world.
Not all dogs mirror us: The case of ancient and solitary hunters
The 2021 follow-up study explored whether this synchronisation was a universal feature of the dog–human bond or one shaped by specific breed histories. It included:
Ancient breeds (e.g., Basenjis, Akitas) with genetic proximity to wolves and minimal selection for human cooperation.
Solitary hunting breeds (e.g., Elkhounds, dachshunds), bred to work independently, often at a distance from humans.
Researchers used the same methodology—HCC from hair samples—but added several new layers:
The Monash Dog–Owner Relationship Scale (MDORS) to assess perceived emotional closeness, interaction quality, and the perceived cost of ownership.
Owner and dog personality questionnaires.
Lifestyle data, including kennel use, household composition, training routines, and physical activity.
Key result: No significant correlation was found between dog and owner HCC in either ancient or solitary hunting breeds. Unlike the herding group, there was no physiological synchrony.
This absence was not due to measurement artefacts. Dogs from these groups still showed variation in stress levels—but this variation was explained by other factors:
In solitary hunting dogs, dog HCC correlated with owner personality: lower agreeableness and higher openness were associated with higher cortisol levels in dogs.
In ancient breeds, owner personality had no clear effect, but there was a trend suggesting increased HCC in dogs rated as more aggressive toward people.
The perceived cost of ownership (MDORS subscale) significantly predicted dog HCC in solitary hunting breeds and showed a negative correlation in herding breeds.
This suggests that stress synchronisation may be a behavioural adaptation linked to specific selection pressures—namely, those for cooperative work with humans.
Costly companions? The burden of ownership and its physiological impact
Across both studies, the "Perceived Costs" subscale of the MDORS consistently emerged as a significant predictor of dog HCC:
Solitary hunting breeds: Higher perceived cost → higher dog stress.
Herding breeds: Higher perceived cost → lower dog stress.
This divergence is intriguing. In cooperative breeds, a high cost rating may reflect intense involvement—training, working, competing—which paradoxically could provide structure and routine that buffers against chronic stress. In contrast, high perceived cost in solitary hunters may signal unresolved tension, frustration, or misalignment between human expectations and canine behaviour.
This finding reframes the idea of “difficult dogs”—in some cases, what owners experience as difficulty may translate into measurable physiological stress in the animal, especially in breeds less attuned to human emotional cues.
Owner traits and breed sensitivity: A complex interplay
The studies show that owner personality matters—but how it matters depends on the dog’s breed and working history.
In herding dogs, personality traits associated with emotional regulation (neuroticism, conscientiousness) had measurable effects. For instance, more neurotic owners had dogs with lower cortisol, perhaps due to increased attentiveness or emotional availability.
In solitary hunting dogs, traits linked to openness and agreeableness were more predictive. Dogs paired with owners low in agreeableness may experience inconsistent social cues or less predictable interactions, which can be stressful in breeds not selected to “read” humans intuitively.
These findings underscore the importance of matching owner temperament with breed tendencies—not just for training success, but for long-term welfare.
Seasonal stress and lifestyle buffering
Both studies documented a consistent seasonal effect: dog HCC was higher in winter. This may reflect changes in routine, reduced daylight, or lower physical activity. Crucially, owners did not show the same seasonal variation, reinforcing that this was not a shared environmental artefact.
The effect was most marked in pet dogs and in Shetland Sheepdogs. Competing dogs—those regularly engaged in structured training or sports—showed less seasonal fluctuation, suggesting that enriched environments may act as buffers against winter-related stress.
Rethinking the “emotional sponge”
A common narrative in pet-owner culture is that dogs “absorb our emotions.” These studies complicate that idea. Emotional synchronisation is not universal; it varies by breed, context, and relationship quality.
Herding breeds—selected for close visual, spatial, and emotional coordination with humans—do appear to “mirror” their owners. But other breeds may be less attuned or less affected. Emotional contagion is not a blanket feature of domestication; it is shaped by thousands of years of functional selection.
This insight is not just academic—it’s practical. When we understand how different dogs process and reflect human emotion, we can design better training, enrichment, and welfare strategies. We can also avoid over-interpreting our dog’s behaviour through a human lens.
Sources:
Höglin, A., Van Poucke, E., Katajamaa, R., Jensen, P., Theodorsson, E. & Roth, L. S. V. Long‑term stress in dogs is related to the human–dog relationship and personality traits. Sci. Rep. 11, 8816 (2021).
Sundman, A.-S., Van Poucke, E., Faresjö, Å., Theodorsson, E. & Roth, L. S. V. Long-term stress levels are synchronized in dogs and their owners. Sci. Rep. 9, 7391 (2019).
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