Not only do we crave simple explanations but we are often influenced by celebrities or those who may have their own agenda. Researchers at McMaster University in Hamilton, Ontario suggest that we listen to celebrities because of a herding instinct. This is the tendency to make decisions based based both on what others have done in similar situations and the halo effect which gives celebrities an aura of trust extending beyond their expertise. Steven Hoffman, the author of that study, told a recent public panel that listening to Jenny McCarthy (the anti-vaccine proponent) and Dr. Oz is bad for your health.