Look closely at the passage where Holden describes Harris Macklin, one of his former roommates. At first, Holden tells us that Harris was a bore, but then he discovered - and enjoyed - Harris' hidden talent. What was Harris' talent? What does Holden's shifting view of Harris show us about his emotional maturity?

Harris's talent was whistling.

Explanation:

Harris is wonderful at whistling. At first, holden has stopped wonderful painting his former prep school student with one single brush. Harris is the first person to annoy holden and still be able to earn his respect, this and not entering the museum are both positive signs that holden is entertaining more mature views. However, he is becoming more mature but he thinks it is weird.