A large portion of any human population that is easily gullible to any religion, political party, or social trend no matter how preposterous. Gullibillies exist in every race, class, culture, or society and their beliefs are dictated more by demographics than actual intellect, basic cognition, or critical examination. Until a gullibilly becomes hardwired, they can be easily swayed into any belief system.
Guy 1 (To Guy 2): "So why are you a Mormon?"
Guy 2: "Because I chose to be."
Guy 1: "Really? Even though your mom and dad are Mormon, as well as everyone else in your family and community. You sir, are a gullibilly."
Guy 2: "No I'm not! What I believe in is backed up by reason and facts."
Guy 1: "No, it's backed up by someone else's reason and facts which you comfortably don't feel the need to look into. If you were born in Afghanistan, you'd be the same kind of idiot who runs into a Jewish market with a bomb strapped to your chest."