Campaigns aimed at helping individuals quit smoking, drinking or taking drugs will often use images of ex-addicts and even current addicts at the forefront of their advertisements. Whether it's an ex-smoker speaking through a machine because of throat cancer, or a heroin addict under the control of her addiction, there’s no denying the power in seeing someone who has actually been through it telling others to quit. Even if you don’t smoke, drink or do drugs, you can still appreciate how effective such images are.
This technique is called Defector- confidant altercast. A defector is someone who takes a position opposite to their apparent self- interest. So in the advertisement above the defector would be the addict, their apparent self- interest, the drugs. The defector causes the audience to become attentive confidants. The defectors words creates surprise, we feel they are speaking the truth and therefore can be trusted. In general arguing against one’s self interest increases the overall effectiveness of the communication.
This technique was demonstrated in a study by Walster, Aronson and Abrahams (1966). The researchers predicted that a communicator regardless of prestige, will be more effective and perceived as more credible, when arguing for a position opposed to his own best interest. In the study participants were told that the experiment aimed to see how they felt about particular topics, one being the level of power the courts have. The experimenter stated ‘We've found that many people feel the courts have too much power and that the innocent defendant has hardly any chance of getting a fair deal. Others feel the courts have hardly any power and most real criminals never get the punishment they deserve.’ Participants were then given booklets containing a newspaper article with either a high prestige (prosecutor who had sent more criminals to prison than any other) or low prestige (criminal serving 3rd year of 20 year sentence) source arguing that the courts should have more/ less power.
As shown in Figure 1, the results supported the predictions. The criminal was much less effective than the prosecutor when both were arguing that the courts had too much power and slightly more effective than the prosecutor when both were arguing that the courts needed more power. You can see the huge increase in effectiveness of the communicator when the criminal advocated less powerful courts compared to more powerful courts. When the criminal advocated more powerful courts he was clearly arguing against his own best interest. The researchers found that this increased the expertise attributed to the criminal and the extent to which subjects felt they were influenced by him.
So when a person is communicating a message that is against their self- interest we tend to find it more effective. In the advertisement above, we look at the girl and are surprised that an addict is not advocating the use of heroin, rather telling others not to try it. She knows what she’s talking about, she's tried it and its taken control of her, so if she’s saying heroin is so bad then we must listen up.
Walster, E., Aronson, E., & Abrahams, D. (1966). On increasing persuasiveness of a low prestige communicator. Journal of experimental social psychology, 2, 325-342.