Informal reasoning fallacies belong to a persuasive tactic, leading to a conclusion that is not supported by premises but reached through emotions and/or misleading and incomplete information. Previous research focused on the ability to recognize informal reasoning fallacies. However, the recognition itself does not necessarily mean immunity to their influence on decisions made. An experiment was designed to study the relationship between the presence of informal reasoning fallacies and a consequent decision. Having conducted paired comparisons of distributions, we have found some support for the hypothesis that informal reasoning fallacies affect decision-making more substantially than non-fallacious reasoning—strong support in the case of a slippery slope, weak in that of appeal to fear, anecdotal evidence argument defying evaluation. Numeracy and cognitive reflection seem to be associated with higher resistance to the slippery slope, but do not diminish appeal to fear.
Engineering Students’ Beliefs about Decision Making in Capstone Design: A Revised Framework for Types of Informal Reasoning
