The scientists tested similarly raised dogs and wolves that lived in packs. Two animals of each species were placed in adjacent cages, equipped with a buzzer apparatus. When the dog or wolf pressed it with their paw, both animals got a reward on some occasions. Other times, the dog or wolf doing the task got nothing while the partner did.

The key finding was that when the partner got a high value treat, the animal doing the task refused to continue with it.

The question of social status or hierarchy also played an important role in the experiments with dogs and wolves of higher rank taking umbrage more quickly.

The human impact on dogs isn’t entirely absent though. Pet dogs are less sensitive to being treated unfairly – probably because of their experience with us!