The psychology of persuasion

    One of the things that has interested me for a long time is the study of persuasion. How do you make a belief seem reasonable to someone else? A communications professor from Northwestern University named Daniel O?Keefe has devoted his life to this question. O?Keefe collected 107 studies on persuasion over a 50-year period, which together measured the behavior of over 20,000 participants.

    O?Keefe found that when you are making an argument for your position, you should mention the opposing position. The key is that after you have presented the opposing views, you need to make counter-arguments to it. If you do not provide counter-arguments to your opponent?s position, O?Keefe discovered that this is even less persuasive than a simple one-sided argument in which you present only your side.

    This research confirms my own experience of listening to commentators on television. My impression is that a lot of commentators are afraid of appearing weak and thus don?t bring up their opponent?s position. If they do, they misrepresent it so it can be shot down more easily. When I?ve changed my mind on an issue, it?s usually after hearing someone accurately represent my previous belief and then refute it with evidence. 

    There were other findings in O?Keefe?s research which surprised me. It was widely believed that one-sided arguments were better if you were speaking to people who already shared your belief. Interestingly, this is not true. O?Keefe found that two-sided arguments are judged more highly even when you?re preaching to the choir. 

    Another widely held belief is that people with lower levels of education are more easily persuaded by one-sided arguments. The theory was that lesser educated people were simple-minded, and that simple arguments would be more appealing than complicated two-sided arguments. However, O?Keefe found no evidence for this. 

    The one exception to the idea that ?two sides are better than one? was in advertising. Here, O?Keefe found that counter-arguments in advertising do not matter much in persuading an audience.

    Franklin Boster, a communications professor at Michigan State University, has also done some entertaining research on persuasion. Boster and his colleagues tested different persuasive techniques on strangers, to see if they would look after a bicycle for 10 minutes. They tried a method called ?door-in-the-face,? in which you first make a large request, and when that is turned down, you make a small request, which looks reasonable by comparison.

    Another method was to give ?placebo information,? which was an explanation for why the request should be granted, but which contained no real information. An example would be, ?May I use the photocopier before you, because I need to make some copies?? The other technique they tested was to simply ask the person why they couldn?t comply with the request, and then address the person?s objections.

    The experimenters asked 60 random passers-by to look after the bicycle. The ?why not? method achieved compliance 60 percent of the time, higher than the placebo information technique with 45 percent and much higher than the door-in-the-face approach at 20 percent.

    There is a large body of psychological literature on self-deception ? a phenomenon I believe is related to the success of the ?why not? method. For instance, other psychologists have shown that when you pay a person a large sum of money to do a repetitive task, and then ask them how fun it was afterward, they will tell you it was boring. On the other hand, if you give them a small amount of money, they?re more likely to tell you it was worthwhile. The reason is that in the first case, they know they did the experiment for the money, so they don?t need to search for another justification. But if they can?t find a good reason to explain why they performed the experiment, they convince themselves that it was fun, because they don?t want to believe they wasted that time for nothing.

    I think something similar is going on in Boster?s experiment. If you ask someone to provide a reason for not helping you, and you rebuff the reason they give, they are more likely to cave to your request. Once you?ve removed their reasons to refuse help, they feel pressure, not just from you but also internally, to think you must have a worthy cause.