The takeaway sentence in this article is that the goose "stood up for herself." This means that she reflected the shepherd's emotional charge back at him, and this resistance is what triggered the dog's physical memories of flow, i.e. its puppy mind. Then through a process of elaboration wherein both individuals generate traits on demand (active/reactive/direct/indirect) and which transpires through the core code universal to all emotional beings, so that they in sync project emotion, absorb emotion, and then project it back in a more refined state, heart EVOLVED into existence.
The disposition of physical memory, in how it places the individual within the group, determines the role that the hormonal/neurochemical mix plays in the individual's body/mind. Hormones and neurochemicals don't cause behavior, behavior is an expression of the group dynamic that is supported and executed by the neurochemistry.