How Do People Evaluate Arguments? A Survey Experiment on the Influence of Argument Source

We study the influence of argument source on evaluations of argument validity. More specifically, we ask, whether partial and impartial sources generate different evaluations of argument validity. Previous research has revealed that argument source characteristics like (reputed) expertise or attractiveness can affect people’s evaluation of arguments as well as message acceptance. This means that argument source can be a relevant factor in political, as well as other types of, persuasion. However, there is a lack of knowledge on the influence of source partiality. We explore the source partiality effect via a survey experiment where participants are asked to evaluate socially relevant arguments according to their validity. Arguments concern issues that have been largely debated in Finland, e.g. minority language policy, obligatory immunizations, euthanasia, and immigration. Further, to avoid the influence of participants’ personal opinions on the issues, participants are asked to take a general perspective to argument evaluation. We use two different treatments where the source of the argument is manipulated so that a part of the subjects evaluate arguments presented by a partial source, whereas others evaluate arguments presented by an impartial source. The treatment groups are compared to a control group where argument source is not mentioned. Comparing respondents’ evaluations of argument validity we can extract the influence of argument source. Participants are recruited so that they from a nationally representative sample of the population. In addition to the usual control variables we also look at the interaction between certain personality traits, such as Machiavellianism.