Mariti, C., Carlone, B., Protti, M. et al. 2018. Effects of petting before a brief separation from the owner on dog behavior and physiology: A pilot study. Journal of Veterinary Behavior 27, 41-46.

Human physical contact is known to be effective in decreasing dogs' level of stress, assessed through endocrine, physiological, and behavioral parameters. Gentle touching has been found to be beneficial for dogs while experiencing or after having experienced a stressful event. The aim of the present study was to assess if dog behavior and physiology during a brief separation from the owner were modified by being petted before owner's departure. Ten dogs, not affected by separation-related problems, were tested twice while separated for 3 minutes from the owner: before separation, dogs once were petted for 1 minute and once were not petted. During each test, dog behavior was measured by continuous sampling and saliva collected 15 minutes after separation for cortisol determination. Findings show that, during both procedures, dogs spent a long time looking for the owner (median 84.5 and 87.5 seconds, respectively) and did not seem highly stressed by separation (low salivary cortisol levels and relatively low intensity and frequency of stress signals). When dogs were petted before separation, they displayed behaviors indicative of calmness for a longer period while waiting for the owner's return (Z = −1.955; P = 0.049), and their heart rate showed a marked decrease after the test (Z = −1.682; P = 0.073). This pilot study suggests that petting a dog before a brief separation from the owner may have a positive effect, making the dog calmer during the separation itself. Further studies are needed to analyze more in depth its effectiveness, especially in dogs affected by separation anxiety.