For everyday arguments prior beliefs play a larger role on perceived argument quality than argument quality itself

Not all arguments are equally convincing, and whilst a given argument may be persuasive to some people, it is often seen as inadequate by others. We are interested in both the individual and argument level differences that make 'everyday' arguments such as those on social media persuasive. We investigate this question using a paradigm that consists of two parts. In the first part, we measure participants' individual beliefs about eight claims each referring to a political topic (e.g., Abortion should be legal). In the second part, participants rated the quality of an argument for each of these claims. Arguments were good or bad (Experiments 1 and 2) or good, inconsistent, or authority-based (Experiment 3). Good, inconsistent, and authority-based arguments summarised arguments from an educational bipartisan website, contained internal inconsistencies, or were based on appeals to authority, respectively. We found that participants preferred arguments that were also in line with their beliefs. We also found that participants were able to discriminate the qualities of different arguments - good arguments were rated as better than any other type of argument. In Experiment 3, inconsistent arguments were rated as better than those making appeals to authority. Importantly, the maximum effect of belief was larger than the maximum effect of argument quality. Thus, people do not evaluate arguments independently of the background beliefs held about them, which play at least as large a role in evaluating the quality of the argument as does the actual quality of the argument itself.