Next time you walk into a meeting or make a public speech, leave your arguments at the door. This advice is contrary to what we were taught in school, but it is based on the latest behavioral science research. 

Webster’s gives two definitions for an argument: “1) a coherent series of reasons, statements, or facts intended to support or establish a point of view and 2) an angry quarrel or disagreement.” Public speakers often do the first and sometimes both. 

If a person’s brain were a computer that made an unemotional decision based on which public speaker in a debate had the best argument, following Webster’s definition to give a speech would be perfect for the real world. But behavioral science research proves that such a technique is wrong and sheds light on how the human brain makes emotional imperfect decisions—not perfect decisions based on facts and reasons. 

One of the causes of imperfect decisions is a condition called confirmation bias. That is, the brain forms a belief and will sift through subsequently conflicting information to find only the evidence that supports the initial belief. Although there was no research regarding confirmation bias hundreds of years ago, the principle existed. In 1620, Francis Bacon said, “Once a human intellect has adopted an opinion (either as something it likes or as something generally accepted), it draws everything else in to confirm and support it. Even if there are more and stronger instances against it than there are in its favor, the intellect either overlooks these or treats them as negligible or does some line-drawing that lets it shift them out of the way and reject them.”

Today, Robert Cialdini in his book Pre-Suasion explains that the research on confirmation bias shows that “the best persuaders become the best through pre-suasion—the process of arranging for recipients to be receptive to a message before they encounter it. . . . The answer lies partly in a poorly appreciated tenet of all communication: What we present first changes the way people experience what we present to them next.”

Mark Lanier, internationally recognized as one of the best plaintiff’s lawyers in the country, told me that whenever he walks into a courtroom, he “thinks of presentations, not arguments.” His presentations start with a powerful theme—what I like to call a bottom-line message—because he knows the power of confirmation bias. In a two-month trial against Johnson & Johnson in which he represented plaintiffs who had defective hip replacement implants, Lanier used this theme in his opening statement: “This is a case about six people who trusted a product, trusted a doctor, and got terrible results.” 

What makes Lanier’s bottom-line message better than a heated argument? First, it provides a framework for how the jury will perceive the rest of the facts and reasons he presents. Second, brevity speaks loudly. Third, it is memorable because it uses alliteration (repetition of the same letter at beginning of closely connected words) and anaphora (repetition of same word or phrase at beginning of successive clauses). Finally, Lanier uses the “Rule of Three,” which is a time tested principle that people remember ideas better when they are grouped in a set of three. Most important, it stirs jurors’ emotions. To do that, it must convey a core human value. Lanier uses “trust” as his human value. 

In addition to having a bottom-line message at the beginning of your presentation that takes advantage of confirmation bias, you need to think about the tone of your delivery. Dale Carnegie believes that the only way to win an argument is to avoid it. 

In short, the next time you are in a meeting or giving a speech, use confirmation bias to your advantage. Forget about arguing. Instead, start with a powerful bottom-line message that encompasses a human value. As you deliver your presentation, have a conversation and speak from your heart to persuade.