What can we learn about Junior’s sense of identity from his interaction with Mr. Dodge?

Mr. Dodge is offended that Junior knows so much. He racially mocks him in front of the class,

Okay, Arnold,” Dodge said. “Where did you learn this fact? On the reservation? Yes, we all know there’s so much amazing science on the reservation.”

This makes Junior feel humiliated and frustrated. Junior knows Mr. Dodge is making racial assumptions about Junior and his intelligence yet Junior still holds true to himself.