Of course it's relevant, by definition of "temperament". The question is how much of our (very complex) behavior is biologically based and independent of learning.
For a cat, it probably plays a significant role. Cat behaviors are complex but still much more simpler than humans. And changes are rare. Although I've heard of a "lazy" apathetic cat moving into a house with giant outdoor catio and becoming drastically more active, almost like a different kitty.
I'm not sure about humans - how much of our behavior is a true temperament and how much isn't despite tending to not change throughout one's life. I've seen introverts becoming eager activists after they went through some bad things, like war and prison. I've seen people who were jumpy and always nervous becoming relaxed after many years in safety.
For a cat, it probably plays a significant role. Cat behaviors are complex but still much more simpler than humans. And changes are rare. Although I've heard of a "lazy" apathetic cat moving into a house with giant outdoor catio and becoming drastically more active, almost like a different kitty.
I'm not sure about humans - how much of our behavior is a true temperament and how much isn't despite tending to not change throughout one's life. I've seen introverts becoming eager activists after they went through some bad things, like war and prison. I've seen people who were jumpy and always nervous becoming relaxed after many years in safety.