After decades of research into formal or logical fallacies of reasoning, psychologists have only recently begun to examine the informal reasoning fallacies that are routinely present in critical discussions, debates, and other forms of argumentation. The present study considers several possible influences on an ability to identify and analyze these fallacies. College students completed measures of deductive reasoning, personal epistemology, and knowledge of specific argumentation norms and analyzed arguments containing fallacies such as argument from ignorance, begging the question, and slippery slope. Results indicated that effective analysis of informal fallacies was associated with some aspects of deductive reasoning--especially an ability to overcome belief bias--and with higher-order epistemic beliefs, as well as a commitment to argumentation norms for critical discussion. Results are discussed in terms of argumentation research and implications for pedagogical treatments of the fallacies are noted.