The White Stripes' "A Boy's Best Friend"

This morning I listened to the White Stripes' De Stijl and noticed some lines in "A Boy's Best Friend":

My only friends speak no words to me
But they look at me, and they don't forget
That a boy's best friend
Is his mother or whatever has become his pet

Part of that ("A boy's best friend / Is his mother") seems to be a reference to a line in Alfred Hitchcock's Psycho:  "A boy's best friend is his mother."