"Using a manipulative task, we tested dogs in three conditions, in which we varied the owner's presence and behavior (Experiment 1: "Absent owner", "Silent owner", "Encouraging owner") and in one additional condition, in which the owner was replaced by an unfamiliar human (Experiment 2: "Replaced owner"). We found that the dogs' duration of manipulating the apparatus was longer when their owner was present than absent, irrespective of the owner's behavior. The presence of an unfamiliar human however did not increase their manipulation."
I wonder if this effect applies to horses. Based on anecdotal evidence, I have found Blessi quicker to explore new items when I am present and provide encouraging words. However, Blessi has always been the type of horse to explore thoroughly anything new that he finds. Sometimes too thoroughly and I have had to pay some extra boarding fees. I would love to see this experiment replicated with horses.