Table 1.

Ethogram adopted during the test. We recorded the duration of behaviors denoting interest toward the apparatus, the door, the owner and the stranger and categorized them as target-directed behaviors including gazing, interaction and approach. The stress behaviors were also recorded

Behaviors	Description
Approach	The dog approaches the target. This behaviour was recorded when the dog was moving toward the door, the apparatus and the people (irrespectively whether it was gazing toward the face of other part of the body)
Interaction	The dog engages in physical contact with the target. It includes explorative behaviors, such as sniffing (from not more than 20 cm about). Furthermore, physical interaction with muzzle or legs, licking, jumping up the target were also included
Gazing	The dog looks at the target from a stationary position. Gazing behavior toward the people was recorded when clearly directed to the face of the subjects
Stress	All behaviors indicating a stressful response. Includes mouth licking (the dog licks its lips or nose), locomotion (dog walking, pacing or running around without a clear target or exploratory intent), shaking off, scratching, yawning, barking, yapping, panting, drinking water