To bring it back to the animal example. Y'cast a spell. Your mind relaxes its anxiety around animals.
For anyone who actually knows how dogs for instance respond to things. They very much mirror what they see. You are happy, relaxed, and engaged with them - They are happy, relaxed, and engaged with you unless they've got some serious traumatic baggage of their own.
Then you see how much more positively they react to you than to others who by default don't understand animal body-language and are usually neurotically picking behaviors apart like humans do, and even looking for danger, which makes animals more on edge. That confidence and reaffirmation makes it stronger, and pronounces the effects going forward. (edited)