The influence of argument structure on judgements of argument strength, function, and adequacy

The present study explored the extent to which lay adults consider aspects of argument structure in judging the strength and function of informal arguments and in constructing arguments to meet specific adequacy goals. Across two experiments, college students were presented with base (one-premise) arguments, which were then expanded into convergent, coordinate, and subordinate arguments closely matched in terms of content, believability, and strength. Coordinate arguments were associated with the greatest gains in argument strength via their construction and the greatest loss in strength when one of their premises was falsified. To some degree, the argument types were also judged to perform different functions and to serve different goals. The construction of convergent arguments was associated with building independent lines of support while the construction of subordinate arguments was associated with providing justification for premises. Expansion into a coordinate argument was seen as the best way to improve an argument's persuasiveness. The construction of both coordinate and subordinate arguments was associated with building relevance, explicating assumptions, and completing the meaning of a base argument. Results are discussed in terms of argumentation theory and research.