Unbeknown to most pet keepers, pets are very observant. They come to conclusion of whether favouritism is present or not through a different process to that of humans. Its not through deductive reasoning but through conditioning and cognition. For instance, you might cuddle your favourite pet in the prescence of another. Naturally, the other pet would love the same to be done to it and would move closer expecting the same treatment. When you decline to repeat the same action, you will have missed a chance at positive reinforcement through conditioning. If you chase the other pet away, it will associate its presence as negative. But then you continue to positively reinforce another pet and this would now be associated with negativity towards it and therefore positivity towards another pet hence favouritism. It doesn't take long for pets to come to this conclusion as I learnt from two puppies who were fraternal twins. I favoured one over the other since it was gentler. I learnt from my mistake and would hesitate to lower the self esteem of a pet.
