The my-side bias is a well-documented cognitive bias in the evaluation of arguments, in which reasoners in a discussion tend to overvalue arguments that confirm their prior beliefs, while undervaluing arguments that attack their prior beliefs. The first part of this paper develops and justifies a Bayesian model of myside bias at the level of individual reasoning. In the second part, this Bayesian model is implemented in an agent-based model of group discussion among myside-biased agents. The agent-based model is then (...) used to perform a number of experiments with the objective to study whether the myside bias hinders or enhances the ability of groups to collectively track the truth, that is, to reach the correct answer to a given binary issue. An analysis of the results suggests the following: First, whether the truth-tracking ability of groups is helped or hindered by myside bias crucially depends on how the strength of myside bias is differentially distributed across subgroups of discussants holding different beliefs. Second, small groups are more likely to track the truth than larger groups, suggesting that increasing group size has a detrimental effect on collective truth-tracking through discussion. (shrink)

How should the state justify its coercive rules? Public reason liberalism endorses a public justification requirement: Justifications offered for authoritative regulations must be acceptable to all members of the relevant public. However, as a criterion of legitimacy, the public justification requirement is epistemically unreliable: It prioritizes neither the exclusion of false beliefs nor the inclusion of true beliefs in justifications of political rules. This article presents an epistemic alternative to the public justification requirement. Employing epistemological theories of argumentation, we demonstrate (...) how this approach enables assessing the epistemic quality of justifications of political rules, even when the truth is difficult to establish. (shrink)

According to the Bayesian paradigm in the psychology of reasoning, the norms by which everyday human cognition is best evaluated are probabilistic rather than logical in character. Recently, the Bayesian paradigm has been applied to the domain of argumentation, where the fundamental norms are traditionally assumed to be logical. Here, we present a major generalisation of extant Bayesian approaches to argumentation that (i)utilizes a new class of Bayesian learning methods that are better suited to modelling dynamic and conditional inferences than (...) standard Bayesian conditionalization, (ii) is able to characterise the special value of logically valid argument schemes in uncertain reasoning contexts, (iii) greatly extends the range of inferences and argumentative phenomena that can be adequately described in a Bayesian framework, and (iv) undermines some influential theoretical motivations for dual function models of human cognition. We conclude that the probabilistic norms given by the Bayesian approach to rationality are not necessarily at odds with the norms given by classical logic. Rather, the Bayesian theory of argumentation can be seen as justifying and enriching the argumentative norms of classical logic. (shrink)

Many experiments suggest that participants are more critical of arguments that challenge their views or that come from untrustworthy sources. However, other results suggest that this might not be true of demonstrative arguments. A series of four experiments tested whether people are influenced by two factors when they evaluate demonstrative arguments: how confident they are in the answer being challenged by the argument, and how much they trust the source of the argument. Participants were not affected by their confidence in (...) the answer challenged by the argument. By contrast, they were sometimes affected by their trust in the argument’s source. Analyses of reaction times and transfer problems suggest that source trustworthiness did not directly affect argument evaluation, but affected instead the number of times the participants considered the arguments. Our results thus suggest that people can evaluate demonstrative arguments objectively. In conclusion, we defend the hypothesis that people might also be able to evaluate non-demonstrative arguments objectively. These results support the predictions of the argumentative theory of reasoning. (shrink)

Minimal adversariality consists in the opposition of contradictory conclusions in argumentation, and its usual metaphorical expression as a game between combating arguers has seen it be criticized from a number of perspectives: the language used, whether cooperation best attains the argumentative telos of epistemic betterment, and the ideal nature of the metaphor itself. This paper explores primarily the idealization of deductive argumentation, which is problematic due to its attenuated applicability to a dialectic involving premises and justificatory biases that are left (...) hidden and unelucidated. To clarify the issue and offer up a solution, we consider minimal adversariality as an involuntary state of affairs before relating this interpretation to a link between rational persuasion and the attainment of epistemic betterment. Through this we see how the idealizing tendencies of minimal adversariality can be reduced even in argumentation involving premises whose justifications for any arguer are inaccessible to any other arguer. (shrink)

High-quality arguments have strong and lasting persuasive effects, suggesting that people can distinguish high- from low-quality arguments. However, we know little of what norms people employ to make that distinction. Some studies have shown that, in evaluating arguments from consequences, people are more sensitive to differences with respect to the desirability of these consequences than to differences in the likelihood that these consequences will occur. This raises the question of whether people lack the criteria to distinguish high-quality from low-quality arguments (...) in support of such claims. In an experiment, 196 participants without any training in argument theory rated their acceptance of 30 claims about the likelihood that a certain outcome would result from a certain action. These claims were supported by an argument from authority, or from cause to effect, or from example. Arguments were systematically manipulated to violate nine specific criteria. For seven out of the nine criteria violation decreased acceptance of the claim supported. These findings show that people can use argument type specific criteria to distinguish high- from low-quality arguments. (shrink)

(2013). Rational argument, rational inference. Argument & Computation: Vol. 4, Formal Models of Reasoning in Cognitive Psychology, pp. 21-35. doi: 10.1080/19462166.2012.689327.

ABSTRACTThe ability to evaluate scientific claims and evidence is an important aspect of scientific literacy and requires various epistemic competences. Readers spontaneously validate presented information against their knowledge and beliefs but differ in their ability to strategically evaluate the soundness of informal arguments. The present research investigated how students of psychology, compared to scientists working in psychology, evaluate informal arguments. Using a think-aloud procedure, we identified the specific strategies students and scientists apply when judging the plausibility of arguments and classifying (...) common argumentation fallacies. Results indicate that students, compared to scientists, have difficulties forming these judgements and base them on intuition and opinion rather than the internal consistency of arguments. Our findings are discussed using the mental model theory framework. Although introductory students validate scientific information against their knowledge and beliefs, the.. (shrink)