In theory, flawed arguments are not individually sufficient to justify a conclusion, but several may converge to do so. This is an empirical study of how arguers respond to a series of imperfect causal arguments during a serious conversation. People became less critical of the flawed arguments as more of the arguments appeared. The study gives empirical evidence that ordinary arguers permit sufficiency to accumulate during an extended discussion.

In this paper, it is argued that a pragma-dialectical perspective on advisory health brochures can complement current research in the medical domain and vice versa. Advisory health brochures are characterized as a particular communicative activity type to show how this context influences the argumentative process. It is argued that the quality of argumentation in health communication needs more attention. Insights from behavioural theory and persuasion research may help to detect possibly fallacious manoeuvres.

Argumentation is pervasive in everyday life. Understanding what makes a strong argument is therefore of both theoretical and practical interest. One factor that seems intuitively important to the strength of an argument is the reliability of the source providing it. Whilst traditional approaches to argument evaluation are silent on this issue, the Bayesian approach to argumentation (Hahn & Oaksford, 2007) is able to capture important aspects of source reliability. In particular, the Bayesian approach predicts that argument content and source reliability (...) should interact to determine argument strength. In this paper, we outline the approach and then demonstrate the importance of source reliability in two empirical studies. These experiments show the multiplicative relationship between the content and the source of the argument predicted by the Bayesian framework. (shrink)

Although argumentation plays an essential role in our lives, there is no integrated area of research on the psychology of argumentation. Instead research on argumentation is conducted in a number of separate research communities that are spread across disciplines and have only limited interaction. With a view to bridging these different strands, we first distinguish between three meanings of the word ?argument?: argument as a reason, argument as a structured sequence of reasons and claims, and argument as a social exchange. (...) All three meanings are integral to a complete understanding of human reasoning and cognition. Cognitive psychological research on argumentation has focused mostly on the first and second of these meanings, so we present perspectives on argumentation from outside of cognitive psychology, which focus on the second and third. Specifically, we give anoverview of the methods, goals, and disciplinary backgrounds of research on the production, the analysis, and the evaluation of arguments. Finally, inintroducing the experimental studies included in this special issue, which were conducted by researchers from a range of theoretical backgrounds, weunderline the breadth of argumentation research as well as stress opportunities for mutual awareness and integration. (shrink)

Whereas there are many publications in which argumentation quality has been defined by argumentation theorists, considerably less research attention has been paid to lay people’s considerations regarding argument quality. Considerations about strong and weak argumentation are relevant because they can be compared with actual persuasive success. Argumentation theorists’ conceptions have to some extent been shown to be compatible with actual effectiveness, but for lay people such compatibility has yet to be determined. This study experimentally investigated lay people’s expectations about the (...) persuasiveness of anecdotal, statistical, causal, and expert evidence, and compared these expectations with the actual persuasiveness of these evidence types. Dutch and French participants (N = 174) ranked four types of evidence in terms of their expected persuasiveness for eight different claims. Both cultural groups expected statistical evidence to be the most persuasive type of evidence to other people, followed by expert, causal, and, finally, anecdotal evidence. A comparison of these rankings with the results of Hornikx and Hoeken (Communication Monographs 74, 443–463, 2007, Study 1) on the actual persuasiveness of the same evidence types reveals that people’s expectations are generally accurate: How relatively persuasive they expect evidence types to be often corresponded with their actual persuasiveness. (shrink)

Norms—that is, specifications of what we ought to do—play a critical role in the study of informal argumentation, as they do in studies of judgment, decision-making and reasoning more generally. Specifically, they guide a recurring theme: are people rational? Though rules and standards have been central to the study of reasoning, and behavior more generally, there has been little discussion within psychology about why (or indeed if) they should be considered normative despite the considerable philosophical literature that bears on this (...) topic. In the current paper, we ask what makes something a norm, with consideration both of norms in general and a specific example: norms for informal argumentation. We conclude that it is both possible and desirable to invoke norms for rational argument, and that a Bayesian approach provides solid normative principles with which to do so. (shrink)