Attitude is determined by an intellectual decision – a personal judgment – this is right and that is wrong.
Your character’s point of view may be that the indiscriminate slaughtering of dolphins and whales is morally wrong because they are two of the most intelligent species on the planet, maybe smarter than men. Your character supports that point of view by participating in demonstrations and wearing T-shirts with Save the whales and dolphins on them. That’s an aspect of characterization. Syd Field – The Screen Writer’s Workbook.
While there many paradigms through which you might view character arc change, the one that appeals most to me is based on the concept of Jungian ‘individuation’.