Catfish is Too Smart?

I read that chicken livers make good bait for catching catfish. I usually eat the liver, however, so I used a chicken lung instead. I did my typical 15 minutes of urban fishing this morning and while there was some "activity" around my baited hook, I did not catch anything. This is not uncommon, as one can frequently go fishing and not catch anything. But I had to wonder... if the catfish knew that I had substituted an "inferior" type of organ meat? Maybe that catfish was too smart to fall for my substitution! After all, I wouldn't eat the lung. On the other hand... maybe the fish just wasn't hungry or it was on the other side of the lake...