might affect their choices . They met at Emory University in Atlanta , Georgia , where psychologist Drew Westen studies how brains react to candidates ' messages . Westen , who wrote `` The Political Brain , '' said fear-based attack ads are effective because they tap into a voter 's subconscious . `` Those kinds of gut-level reactions tell us things like , ' I do n't feel like this person is telling us the truth , ' '' Westen said . `` Unless someone is a really good con man , those reactions are extremely helpful . The conscious brain processes only a tiny percent of information . '' Westen and his business partner , Joel Weinberger , have created software , through their company ThinkScan , that looks into a voter 's subconscious . The software does this by measuring people 's reaction time to certain words after they watch attack ads . The undecided voters in CNN 's group watched the ads and were then asked to identify the color of words such as `` weak , '' `` inexperienced '' and `` terrorist . '' If they hesitated , even for one-thousandth of a second
ATLANTA , Georgia -LRB- CNN -RRB- -- Terrorism , a slow economy and rising gas prices are issues that can keep American voters awake at night . Undecided voters gathered at Emory University , where Dr. Drew Westen studies how brains react to messages . Political strategists know that the most successful candidates are masters at capitalizing on fears such as these , and that can make a huge difference at the polls . In 1964 , Lyndon Johnson was running for president against conservative Barry Goldwater when his campaign unleashed the `` daisy ad . '' It showed a little girl counting as she plucked a daisy , charmingly mixing up her numbers . Then a baritone voice takes over , counting down to an overwhelming nuclear explosion . It 's followed with a warning that the stakes are too high not to vote for Johnson . The ad , which ran only once , was so chilling and effective , analysts say , it helped Johnson win the presidency by one of the widest margins in U.S. history . CNN recently gathered eight undecided voters to see how they would respond to attack ads and how the ads