What does Atticus mean when he says, "try fighting with your head for a change"?

“You just hold your head high and keep those fists down. No matter what anyone says to you, don’t let ‘em get your goat. Try fighting with your head for a change…it’s a good one, even if it does resist learning.” (Atticus page. 76, chapter 8)

He means try thinking and using your mind before you act impulsively and hit someone. Fight with your mind....