As you give feedback or input to a person, their emotional brain may deflect or defend against it, depending on their beliefs of who they are as a person, and their perception of you as a leader. Your goal in giving great feedback is to help them move from a reaction (their emotional brain) to a decision (cognitive brain).
Once someone moves beyond their emotional reaction and begins to consider your input, they begin to make choices about what could work for them, and how to do it. When exploring and learning how to do this new thing, they may start to believe this could work for them. This is the area you as a leader want to work in when giving your input or feedback.