Differences in stimulus aversiveness among sheep have been detected using an arena that creates approach/avoidance motivational conflict. More specifically, the procedure involves placing a stimulus between an individual sheep and a group of companions. In this particular study, the stimuli that were tested included: a box, goat, human and dog. Based on the behavioural reactions during the test, the authors speculated on the relative aversiveness of the human compared to the dog and goat. Each sheep was exposed to the stimulus for 10 min. The results indicated that the sheep stayed further away from their companions when a dog was present in the arena. When the dog was present, the sheep explored very little and were very vigilant. When the human and goat were in the arena, the sheep kept an intermediate distance from their companions, and their vigilance and exploration were also intermediate. The main difference in their response to a human and goat was that the sheep sniffed the goat more than the human. More fear-related behaviour occurred because of the human than the goat. This type of test is very useful for measuring relative aversiveness of different stimuli. The dog was most aversive and the human was slightly more aversive than the goat.