ANIMAL COGNITION · RESEARCH REVIEW · OCTOBER 17, 2026

Can Dogs Smell Human Stress?

What research actually shows about human emotions and canine decision-making.

Dogs are highly sensitive to human behavior, but their ability to detect human stress extends beyond our voices and facial expressions. A peer-reviewed study suggests that chemical cues in human odor may affect how dogs respond to uncertain situations—even when the scent comes from an unfamiliar person.

What scientists tested

In a 2024 Scientific Reports study, Parr-Cortes and colleagues tested 18 dogs using odor samples collected from people during stressful and relaxing activities. Dogs learned that a food bowl in one location contained a reward, while another location did not. Researchers then measured their responses to bowls in ambiguous positions, under different odor conditions.

What they found

Dogs exposed to human stress odor were less likely to approach a bowl in one ambiguous, near-negative position compared with a no-odor control—but this significant effect appeared in the third test session. The authors interpreted the behavior as potentially more cautious or 'pessimistic' decision-making. There were also interactions between odor exposure, test session and learning.

What this does not prove

The study did not directly measure changes in dogs' brain wiring or demonstrate permanent neurological changes. It did not establish that every owner's passing bad mood harms their pet. Its sample was small, and the observed effect depended on the testing condition and session. Behavioral responses are an indirect window into an animal's emotional state.

Why it matters

The results raise questions about how human stress might influence dogs in homes, shelters, veterinary clinics and working-dog settings. Replication with larger samples and direct physiological measures would help clarify the mechanisms and practical implications.

Read the original research

• Parr-Cortes et al. (2024), The odour of an unfamiliar stressed or relaxed person affects dogs’ responses to a cognitive bias test, Scientific Reports
• University of Bristol: research explanation
• PubMed record (PMID 39039125)

Discuss the science

Have you observed your dog responding differently when someone is stressed? Anecdotes can inspire research questions, but are not proof of a mechanism. Discuss this topic in MKP's community forum.

Evidence classification: peer-reviewed experimental animal-behavior study; preliminary due to small sample and condition-specific results. This is an original MKP summary, not a reproduction of the news article.