Answer:
It determines how much information the reader can access.
Step-by-step explanation:
For example, in first person perspective the character acts as the narrator which forces the reader to take their word for any and every situation that happens. If they exclaim they dislike someone because the person is mean to them how would you know if the person is mean to them based on their description alone? First person perspective is prone to having a distortion of the truth. Another example is third-person limited perspective. If you only have access to one character's thoughts and not how all characters feel about situations as well as each other, this puts a limit on our understanding of the story and of the other characters.