When I was in seventh grade at Westfield Junior High, the gym locker room was a cruel place.

Our physical education teacher was a nice guy, but he was very passive, and we were usually unsupervised as we changed into and out of our gym uniforms each day. And a pack of 13-year-old boys can stir up a lot of trouble in 10 minutes.

One boy was punched in the arm day after day. I can remember my classmates lining up and each slugging him hard in the upper arm as they filed past his locker. I remember, too, seeing that the boy’s biceps once: They were covered in purple bruises.