Fear - based attack ads are sometimes used by candidates to influence voters . CNN interviewed eight undecided voters to measure the effectiveness of attack ads . Author Drew Pearson says fear - based ads appeal to voters ' subconscious .
Fear-based attack ads are sometimes used by candidates to influence voters . CNN gathered eight undecided voters to measure the impact of attack ads . Psychologist Drew Westen says fear-based ads appeal to voters ' subconscious .