Stress travels down the lead but also through the air – Presented by Nicola Rooney

We have long known that dogs can tell when a person or their handler is stressed. However, our team have recently explored both whether they can distinguish using remote odour samples alone and importantly whether smelling stress impacts a dog’s cognitive and emotional state.

Eighteen dogs each participated in three cognitive bias sessions: baseline (no odour), stress odour and relax odour, with the order of the two test odours counterbalanced across dogs. The odours were combined breath and sweat samples from three volunteers showing measurable stress responses during a stress test compared to a relaxing activity. We found that dogs were significantly less likely to approach an ambiguous (near negative) location in the presence of stress odour. They were also significantly less likely to approach the trained unrewarded (negative) location and more likely to approach the rewarded (positive) location in the presence of both human odours. Learning over sessions and the order in which odours were presented also had significant effects, with the combination of stress odour and the last testing session having the greatest effect. This is the first study to show that in the absence of visual or auditory cues, olfactory cues of stress from an unfamiliar person may affect dogs’ cognition and learning. This could have important consequences for dog welfare and performance, and implications for the way we train working dogs.

We also conducted a further study on 58 medical detection dogs and found that difference in dog’s performance at their working role were significantly correlated with their responses in the same judgement bias test. Dogs showing optimistic responses in the test tended to perform better as medical assistance dogs, whilst those showing more pessimistic choices tended to show greatest specificity. Together these studies (and others we will also discuss) suggest that judgment biases maybe be important predictors to working dog performance, and human stress may impact these biases and consequently dog performance and welfare.

Coming soon.