What do we call positive behaviours?

Read the following description of Arthur and Ellis, and then identify who is the introvert and who is the extrovert:

Arthur is 19 years old; his best friend Ellis has known him for nearly 10 years now. They met at school. At first, they did not like each until they both ended up in detention together. Since then, they have been inseparable. People refer to them as brothers.

Although they are best friends, Arthur and Ellis do have different interests. Arthur loves to read; he loves the escape of a fantasy novel and wants to go to University to study History. Whereas Ellis loves to play football and dreams of being a professional footballer. Ellis likes the idea of being famous and rich.

They both share a mutual interest in cars. Often, they watch TV shows about cars together and fantasise about going on a road trip across America. When they were younger, they would discuss the cars they would have when they grew up.

Arthur wants eventually to be an author writing novels about historical events. Ellis currently is working for Amazon delivering parcels while he attends the local sports academy.