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)

The notion of “the burden of proof” plays an important role in real-world argumentation contexts, in particular in law. It has also been given a central role in normative accounts of argumentation, and has been used to explain a range of classic argumentation fallacies. We argue that in law the goal is to make practical decisions whereas in critical discussion the goal is frequently simply to increase or decrease degree of belief in a proposition. In the latter case, it is (...) not necessarily important whether that degree of belief exceeds a particular threshold (e.g., ‘reasonable doubt’). We explore the consequences of this distinction for the role that the “burden of proof” has played in argumentation and in theories of fallacy. (shrink)

Short abstract (98 words). Reasoning is generally seen as a means to improve knowledge and make better decisions. However, much evidence shows that reasoning often leads to epistemic distortions and poor decisions. This suggests that the function of reasoning should be rethought. Our hypothesis is that the function of reasoning is argumentative. It is to devise and evaluate arguments intended to persuade. Reasoning so conceived is adaptive given humans’ exceptional dependence on communication and vulnerability to misinformation. A wide range of (...) evidence in the psychology of reasoning and decision making can be reinterpreted and better explained in the light of this hypothesis. (shrink)

Many public information documents attempt to persuade the recipients that they should engage in or refrain from specific behaviour. This is based on the assumption that the recipient will decide about his or her behaviour on the basis of the information given and a rational evaluation of the pros and cons. An analysis of 20 public information brochures shows that the argumentation in persuasive brochures is often not marked as such. Argumentation is presented as factual information, and in many instances (...) the task of making argumentational links and drawing conclusions is left to the reader. However, since the information offered does follow familiar argumentational schemes, readers can, in principle, reconstruct the argument. All the brochures make use of pragmatic argumentation (argumentation from consequences),i. e.,they formulate at least certain benefits of the desirable behaviour or disadvantages of the undesirable behaviour. In addition, they make regular use of argumentation from cause to effect and argumentation from example. Argumentation from rules and argumentation from authority are less frequently used. This empirical analysis of the use of argumentation schemes is a solid base for interesting and rich hypotheses about the cognitive processing of persuasive brochures. Central processing requires the reader to be able to reconstruct argumentation from informational texts and to identify and evaluate various types of argumentation. (shrink)

We examine in detail three classic reasoning fallacies, that is, supposedly ``incorrect'' forms of argument. These are the so-called argumentam ad ignorantiam, the circular argument or petitio principii, and the slippery slope argument. In each case, the argument type is shown to match structurally arguments which are widely accepted. This suggests that it is not the form of the arguments as such that is problematic but rather something about the content of those examples with which they are typically justified. This (...) leads to a Bayesian reanalysis of these classic argument forms and a reformulation of the conditions under which they do or do not constitute legitimate forms of argumentation. (shrink)

Conditional promises and threats are speech acts that are used to manipulate other people's behaviour. Studies on human reasoning typically use propositional logic to analyse what people infer from such inducements. While this approach is sufficient to uncover conceptual features of inducements, it fails to explain them. To overcome this limitation, we propose a multilevel analysis integrating motivational, linguistic, deontic, behavioural, and emotional aspects. Commonalities and differences between conditional promises and threats on various levels were examined in two experiments. The (...) first shows that both types of inducements are understood as being complementary on the linguistic level, but not reversible, due to the specific temporal order of their actions. In addition, it gives a first assessment of emotional reactions. The second experiment investigated the novel question of whether complementary promises and threats, despite semantic differences, both imply an obligation to cooperate on the deontic level. The data corroborate this hypothesis, and they support various appraisal-theoretical assumptions on the elicitation of emotions. They also reveal that content affects not only the attribution of emotions, but also the deontic interpretation. (shrink)

The main finding of a comprehensive empirical research project on the intersubjective acceptability of the pragma-dialectical discussion rules (Van Eemeren, Garssen & Meuffels, 2009) is that ordinary language users judge discussion moves that are considered fallacious from an argumentation-theoretical perspective as unreasonable. In light of this finding it is remarkable that in everyday argumentative discourse fallacies occur regularly and seem many times not to be noticed by the participants in the discourse. This also goes for the abusive argumentum ad hominem. (...) While abusive ad hominem attacks are judged to be very unreasonable discussion moves when the unreasonableness of clear cases of this fallacy is rated in experiments, in real life this fallacy remains undetected more often than not. In this paper it is argued that this paradox can be explained by analysing abusive ad hominem attacks as a mode of strategic manoeuvring which takes on a reasonable appearance in real life situations when it mimics, as it often does, legitimate critical reactions to authority argumentation. The hypothesis that abusive fallacies are seen as less unreasonable when they are presented as if they are critical questions pertaining to the argument scheme for authority argumentation than when they are clear cases was tested systematically in two experiments. The results of these experiments confirmed the hypothesis. (shrink)

Interaction mining is about discovering and extracting insightful information from digital conversations, namely those human?human information exchanges mediated by digital network technology. We present in this article a computational model of natural arguments and its implementation for the automatic argumentative analysis of digital conversations, which allows us to produce relevant information to build interaction business analytics applications overcoming the limitations of standard text mining and information retrieval technology. Applications include advanced visualisations and abstractive summaries.

In this paper, it is explained that a dialogical approach to complex argumentation can be fruitful for solving two important problems concerning the analysis of the argumentation structure. First, such an approach makes it possible to clarify the distinction between coordinative and multiple argumentation structures, and to identify clues in the presentation for each of these structures. Second, a dialogical approach can provide a basis for dealing more adequately with refutations of counterarguments.

In two experiments, we investigated how people interpret and reason with realistic conditionals in the form of inducements (i.e., promises and threats) and advice (i.e., tips and warnings). We found that inducements and advice differed with respect to the degree to which the speaker was perceived to have (a) control over the consequent, (b) a stake in the outcome, and (c) an obligation to ensure that the outcome occurs. Inducements and advice also differed with respect to perceived sufficiency and necessity, (...) as well as the degree to which these statements were perceived to be effective in changing the behaviour described in the antecedent of the conditional. Multiple regression analyses indicated that perceived control over the consequent, necessity, and sufficiency emerged as the best predictors of (a) the degree to which statements were perceived to be effective in changing the behaviour of the addressee, and (b) inference patterns on a conditional arguments task. (shrink)

Book Review of Luc Bovens and Stephan Hartmann *Bayesian Epistemology* by Erik J. Olsson.

The study of deductive reasoning has been a major paradigm in psychology for approximately the past 40 years. Research has shown that people make many logical errors on such tasks and are strongly influenced by problem content and context. It is argued that this paradigm was developed in a context of logicist thinking that is now outmoded. Few reasoning researchers still believe that logic is an appropriate normative system for most human reasoning, let alone a model for describing the process (...) of human reasoning, and many use the paradigm principally to study pragmatic and probabilistic processes. It is suggested that the methods used for studying reasoning be reviewed, especially the instructional context, which necessarily defines pragmatic influences as biases. (shrink)

The present study examined the effects of semantic structure on simple inductive judgments about category members. For a particular category, subjects were told that one of the species had a given property and were asked to estimate the proportion of instances in the other species that possessed the property. The results indicated that category structure—in particular, the typicality of the species—influenced subjects' judgments. These results were interpreted by models based on the following assumption: When little is known about the underlying (...) distribution of a property, subjects assume that the distribution mirrors that of better-known properties. For this reason, if subjects learn that an unknown property is possessed by a typical species, they are more likely to generalize than if the same fact had been learned about an atypical species. (shrink)

Examining discourse markers (Schiffrin, 1987) in two transcribed discussions of controversial issues in an undergraduate 'critical thinking' class, we note frequent uses of 'I'm just saying' and related metadiscursive expressions (I'm/we're saying, I'm/we're not saying, etc.). Our central claim is that these 'saying' expressions are pragmatic devices by which speakers claim 'all along' to have held a consistent argumentative standpoint, one that continues through the discussion unless changed for good reasons. Through close analysis of a series of discourse examples, we (...) show how these discourse markers are used to display continuity, deflect counterarguments, and acknowledge the force of counterarguments while preserving continuity. In a concluding section we reflect critically on the use of these continuity markers with regard to four pragmatic functions that they potentially serve: to specify and clarify argumentative standpoints, to acknowledge a presumption of standpoint continuity, to acknowledge a normative expectation that discussion participants should have standpoints, and to avoid overt disagreement while saving face. (shrink)

This paper begins a working through of Blair’s (2001) theoretical agenda concerning argumentation schemes and their attendant critical questions, in which we propose a number of solutions to some outstanding theoretical issues. We consider the classification of schemes, their ultimate nature, their role in argument reconstruction, their foundation as normative categories of argument, and the evaluative role of critical questions.We demonstrate the role of schemes in argument reconstruction, and defend a normative account of their nature against specific criticisms due to (...) Pinto (2001). Concerning critical questions, we propose an account on which they are founded in the R.S.A. cogency standard, and develop an account of the relationship between critical questions and burden of proof. Our ultimate aim is to initiate a reconciliation between dialectical and informal logic approaches to the schemes. (shrink)

Argumentation is a very fertile area of research in Artificial Intelligence, and various semantics have been developed to predict when an argument can be accepted, depending on the abstract structure of its defeaters and defenders. When these semantics make conflicting predictions, theoretical arbitration typically relies on ad hoc examples and normative intuition about what prediction ought to be the correct one. We advocate a complementary, descriptive-experimental method, based on the collection of behavioral data about the way human reasoners handle these (...) critical cases. We report two studies applying this method to the case of reinstatement (both in its simple and floating forms). Results speak for the cognitive plausibility of reinstatement and yet show that it does not yield the full expected recovery of the attacked argument. Furthermore, results show that floating reinstatement yields comparable effects to that of simple reinstatement, thus arguing in favor of preferred argumentation semantics, rather than grounded argumentation semantics. Besides their theoretical value for validating and inspiring argumentation semantics, these results have applied value for developing artificial agents meant to argue with human users. (shrink)

In this paper, a survey is presented of the main approaches to the structure of argumentation. The paper starts with a historical overview of the distinctions between various types of argument structure. Next, the main definitions given in the various approaches are discussed as well as the methods that are proposed to deal with doubtful cases.

An adequate evaluation of argumentation requires identification of the object to which the argumentation pertains: the point of view. What are the distinguishing features of this object? In the pragma-dialectical argumentation theory, the object of argumentation is referred to by means of the notion ‘standpoint’. In other theories concerned with argumentation, reasoning, convincing or persuading, notions are used such as ‘thesis’, ‘conclusion’, ‘opinion’ and ‘attitude’. This paper is a survey of the characterisations of the object of argumentation given in the (...) various theories. It discusses the pragma-dialectical argumentation theory, socio-psychological research on persuasion, cognitive research on reasoning, argumentative discourse analysis, two variants of informal logic, advocacy and debate, and the theory of communicative action. Next, it explores some relations between the notions used in these theories. Finally, it outlines some starting points for further research into the problems of identification. (shrink)

Good informal arguments offer justification for their conclusions. They go wrong if the justifications double back, rendering the arguments circular. Circularity, however, is not necessarily a single property of an argument, but may depend on (a) whether the argument repeats an earlier claim, (b) whether the repetition occurs within the same line of justification, and (c) whether the claim is properly grounded in agreed‐upon information. The experiments reported here examine whether people take these factors into account in their judgments of (...) whether arguments are circular and whether they are reasonable. The results suggest that direct judgments of circularity depend heavily on repetition and structural role of claims, but only minimally on grounding. Judgments of reasonableness take repetition and grounding into account, but are relatively insensitive to structural role. (shrink)

The article introduces the concept of ‘argumentational integrity’ as the basis for developing ethical criteria by which contributions to argumentative discussions can be evaluated; the focus is on the derivation, definition, and specification of the concept. The derivation of the concept starts out from a prescriptive use of ‘argumentation’, entailing in particular the goal of a rational as well as a cooperative solution. In order to make this goal attainable, contributions to argumentative discussions must meet certain conditions. It is assumed (...) that participants are not only intuitively aware of these conditions, but in fact expect of themselves and others that they will not consciously violate the conditions. This assumption leads to the most general definition of the norm of argumentational integrity: Speakers must not knowingly violate the argumentative conditions. On the basis of an empirical study drawing upon classifications of unethical strategies in popular rhetorical texts, the general norm is then specified in the form of 11 ‘standards of fair argumentation’. (shrink)

The question addressed in this paper is how the degree of justification of a belief is determined. A conclusion may be supported by several different arguments, the arguments typically being defeasible, and there may also be arguments of varying strengths for defeaters for some of the supporting arguments. What is sought is a way of computing the “on sum” degree of justification of a conclusion in terms of the degrees of justification of all relevant premises and the strengths of all (...) relevant reasons. (shrink)

Argument quality has consistently been shown to have strong and lasting persuasive effects. The question is what criteria people use to distinguish strong from weak arguments and how these criteria relate to the ones proposed in normative argumentation theory. In an experiment 235 participants without training in argumentation theory rated the acceptance of 30 claims about the desirability of a consequence that were supported by either an argument from analogy, from authority, or from consequences. The supporting arguments were systematically manipulated (...) to violate argument type specific criteria. Participants proved sensitive to the violation of most, but not all, argument type specific criteria. From a normative perspective these findings suggest that people act in a fairly adequate way. These findings also enable a more precise description of what people may do when critically appraising arguments, which has important implications for the use of argument quality as a methodological tool in persuasion research. (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)

Bayesian probability has recently been proposed as a normative theory of argumentation. In this article, we provide a Bayesian formalisation of the ad Hitlerum argument, as a special case of the ad hominem argument. Across three experiments, we demonstrate that people's evaluation of the argument is sensitive to probabilistic factors deemed relevant on a Bayesian formalisation. Moreover, we provide the first parameter-free quantitative evidence in favour of the Bayesian approach to argumentation. Quantitative Bayesian prescriptions were derived from participants' stated subjective (...) probabilities (Experiments 1 and 2), as well as from frequency information explicitly provided in the experiment (Experiment 3). Participants' stated evaluations of the convincingness of the argument were well matched to these prescriptions. (shrink)

Three experiments examined the influence of argument length on plausibility judgements, in a category-based induction task. The general results were that when arguments were logically invalid they were considered stronger when they were longer, but for logically valid arguments longer arguments were considered weaker. In Experiments 1a and 1b when participants were forewarned to avoid using length as a cue to judging plausibility, they still did so. Indeed, participants given the opposite instructions did not follow those instructions either. In Experiment (...) 2 arguments came from a reliable or unreliable speaker. This manipulation affected accuracy as well as response bias, but the effects of argument length for both reliable and unreliable speakers replicated Experiments 1a and 1b. The results were analysed using receiver operating characteristic (ROC) curves and modelled using multidimensional signal detection theory (SDT). Implications for models of category-based inductive reasoning, and theories of reasoning more generally, are discussed. (shrink)

This paper analyzes and evaluates the 2007 majority opinion of the German National Ethics Council which seeks to establish new information (as to the inferior quality of legally procurable human embryonic stem cells) as a sufficient reason for a relaxation of the 2002 Stem Cell Law. A micro-level analysis of the opinion’s central section is conducted and evaluated vis à vis the strongest known opponent position in the national debate at that time. The argumentation is claimed to rely on an (...) unsupported semantic assumption regarding the parthood relation of the 2002 compromise and to misconstrue the strongest known opponent position. (shrink)

This article presents an architecture for natural language generation of biomedical argumentation. The goal is to reconstruct the normative arguments that a domain expert would provide, in a manner that is transparent to a lay audience. Transparency means that an argument's structure and functional components are accessible to its audience. Transparency is necessary before an audience can fully comprehend, evaluate or challenge an argument, or re-evaluate it in light of new findings about the case or changes in scientific knowledge. The (...) architecture has been implemented and evaluated in the Genetics Information Expression Assistant, a prototype system for drafting genetic counselling patient letters. Argument generation makes use of abstract argumentation schemes. Derived from the analysis of arguments used in genetic counselling, these mainly causal argument patterns refer to abstract properties of qualitative causal domain models. (shrink)

The paper presents the theoretical and methodological aspects of research on the development of argument- ation in elementary school children. It presents a theoretical framework detailing psychological mechanisms responsible for the acquisition and transfer of argumentative discourse and demonstrates several applications of the framework, described in sufficient detail to guide future empirical investigations of oral, written, individual, or group argumentation performance. Software programs capable of facilitating data analysis are identified and their uses illustrated. The analytic schemes can be used to (...) analyze large amounts of verbal data with reasonable precision and efficiency. The conclusion addresses more generally the challenges for and possibilities of empirical study of the development of argumentation. (shrink)

This article approaches the relationship of normative argumentation studies and descriptive persuasion effects research by pointing to several empirical findings that raise questions or puzzles about normatively-proper argumentative conduct. These findings indicate some complications in the analysis of normatively desirable argumentative conduct – including some ways in which practical persuasive success may not be entirely compatible with normatively-desirable advocacy practices.