The scientifically proven reason for quoting reliable sources

The history of the Elaboration Likelihood Model (ELM) goes as far back as 1979. The model proposes two major routes to persuasion: the central route and the peripheral route. Under the central route, persuasion will likely result from a person's careful and thoughtful consideration of the true merits of the information presented in a text. Under the peripheral route, persuasion results from a person's association with positive or negative cues in said text.

So people who “take” the central route, spend a lot of their attention to the actual arguments that are used to support a claim or theory. Peripheral route readers depend on simpler criteria for decision making, like the number of arguments put forward, or the perceived authority of sources who are quoted to support an argument. Which route is taken, is determined by an individual's motivation and ability to evaluate the argument being presented.

Why does this matter?

People who are less motivated or able to examine a text thoroughly, pay more attention to the source itself than to what he/she has to say. In an experiment set up to test the ELM, respondents were presented with an advert for a fictitious razorblade. Individual motivation was manipulated by telling one half of the subjects they would be able to try out the razorblade in the near future, and letting the other half know the product would not become available for some time. Variations of the advert itself included either strong or weak arguments to promote the razorblade, and endorsements from either famous athletes or random consumers.

The result: subjects with low motivation let themselves be persuaded by the athlete’s endorsement, even when the arguments to promote the product were weak. Subjects with high motivation judged the product by the arguments provided for it, and ignored whoever was endorsing it.

Numbers make it even more interesting

If you regularly use quantitative data in your publications, it’s even more important to pay attention to the ELM. In another experiment, respondents were shown different versions of a television commercial, with the variables being the amount of quantitative data and the expertise of the quoted source. When the commercial showed a lot of quantitative data, subjects were more inclined to believe the source, that is, íf the source was a credible one as far as they could tell.

So: think about your peripheral route readers and carefully select which sources you quote in your publications and commercials. If the source is not seen as a trustworthy expert, this will undermine any arguments, however strong, he/she is making. At the same time, trying to mask weak arguments by using a popular source is never recommended, since your central route readers wíll pay attention to the substantive arguments and see right through your misdirection.