If I were to flip you the bird left-handed, which I sometimes do to mix things up, you’d notice that my middle finger is crooked, with a bulged knuckle. Why does it look like that? Catfish noodling.

Peter Gratton, Ph.D., is a New Orleans-based editor and professor with over 20 years of experience in investing, risk management, and public policy. Peter began covering markets at Multex (Reuters) ...