Reasoning and Argumentation

The psychology of reasoning and argumentation studies how people reason and persuade others using language. Influenced by analytic philosophy, much early work focused on the degree to which verbal reasoning is captured by or diverges from classical deductive logic. From this viewpoint, human thinking can seem prone to substantial and systematic bias. Since 1994, verbal reasoning has been set in the context of uncertain, common-sense reasoning rather than deduction, and reasoning has been seen as continuous with the social challenge of real-world argumentation. From this perspective, the human ability to reason and argue with words is better considered not as flawed logical reasoning, but as often highly competent reasoning and persuasion in an uncertain and contested world.

New Paradigm Psychology of Conditional Reasoning and Its Philosophical Sources

There is a new Bayesian, or probabilistic, paradigm in the psychology of reasoning, with new psychological accounts of the indicative conditional of natural language and of conditional reasoning. Dorothy Edgington has had a major impact on this new paradigm, through her views on inference from uncertain premises, the relation between the probability of the indicative conditional, P(if p then q), and the conditional probability, P(q|p), and the use of the Ramsey test to evaluate conditionals. Accounts are given in this chapter of the psychological experiments in the new paradigm that confirm empirical hypotheses inspired by her work and other philosophical sources.

When nomenclature matters: Is the “new paradigm” really a new paradigm for the psychology of reasoning?

For most its history, the psychology of reasoning was dominated by binary exten-sional logic. The “new paradigm” instead puts subjective degrees of belief centre stage, often represented as probabilities. The term “new paradigm” refers to Thomas Kuhn’s popular theory of science, which describes scientific progress as discontinues process of alternating "normal" and "revolutionary" phases. We argue that the “new paradigm” is too vaguely defined and therefore does not allow a clear decision on what falls within its scope and what does not. We also show that before the new de-velopments, the psychology of reasoning was neither in a phase of normal science, nor is the alleged new paradigm as revolutionary as the term suggests. Based on this analysis, we argue that the supposed opposition between a “new” and “old” para-digms hinders progress in the field. A more productive view is that current progress is developing in continuities where rival research programs stimulate each other in a fruitful way. The article closes with some topics where further connections between competing research programs are likely to promote progress in the psychology of reasoning.

Uncertainty and conjunction fallacies

This chapter examines conjunction fallacies. This phenomenon is a topic in the psychology of reasoning and is not strictly linguistic, but it is related to pragmatics. Monads are shown to capture conjunction fallacies compositionally, which has eluded prominent prior theories. The chapter contrasts a monad built around the probability semiring with one built around a simpler semiring, the one semiring. The choice between the probability and one semirings partially predicts experimental participants’ behaviour. This points to an explanation in terms of the satisficing heuristic, rather than the representativeness heuristic. The chapter explores two options for fully predicting the results. The first is to use Gricean pragmatics in addition to the one semiring. The second is to use alternative underlying semirings for the monad: tropical semirings. This alternative compositional solution achieves a highly satisfying fit with aggregate psychological data and preserves an interesting duality between the logical operations of conjunction and disjunction. Some exercises are provided to aid understanding.

On the interplay between interpretation and reasoning in compelling fallacies

We investigate the articulation between domain-general reasoning and interpretive processes in failures of deductive reasoning. We focus on illusory inferences from disjunction-like elements, a broad class of deductive fallacies studied in some detail over the past 15 years. These fallacies have received accounts grounded in reasoning processes, holding that human reasoning diverges from normative standards. A subset of these fallacies however can be analyzed differently: human reasoning is not to blame, instead the premises were interpreted in a non-obvious, yet perfectly predictable and reasonable way. Once we consider these interpretations, the apparent fallacious conclusion is no mistake at all. We give a two-factor account of these fallacies that incorporates both reasoning-based elements and interpretive elements, showing that they are not in real competition. We present novel experimental evidence in favor of our theory. Cognitive load such as induced by a dual-task design is known to hinder the interpretive mechanisms at the core of interpretation-based accounts of the fallacies of interest. In the first experiment of its kind using this paradigm with an inferential task instead of a simpler truth-value-judgment task, we found that the manipulation affected more strongly those illusions where our theory predicts that interpretive processes are at play. We conclude that the best way forward for the field to investigate the elusive line between reasoning and interpretation requires combining theories and methodologies from linguistic semantics and the psychology of reasoning.

New Paradigms in the Psychology of Reasoning

The psychology of verbal reasoning initially compared performance with classical logic. In the last 25 years, a new paradigm has arisen, which focuses on knowledge-rich reasoning for communication and persuasion and is typically modeled using Bayesian probability theory rather than logic. This paradigm provides a new perspective on argumentation, explaining the rational persuasiveness of arguments that are logical fallacies. It also helps explain how and why people stray from logic when given deductive reasoning tasks. What appear to be erroneous responses, when compared against logic, often turn out to be rationally justified when seen in the richer rational framework of the new paradigm. Moreover, the same approach extends naturally to inductive reasoning tasks, in which people extrapolate beyond the data they are given and logic does not readily apply. We outline links between social and individual reasoning and set recent developments in the psychology of reasoning in the wider context of Bayesian cognitive science.

‘Might’ as a generator of alternatives: the view from reasoning

We argue that the epistemic modal ‘might’ is a generator of alternatives in the sense of Hamblin semantics (Kratzer & Shimoyama 2002) or inquisitive semantics (Ciardelli, Groenendijk & Roelofsen 2009). Building on methodologies from the psychology of reasoning, we show that ‘might’ patterns with disjunctions and with indefinites in giving rise to a particular kind of illusory inference. The best extant accounts of these illusory inferences crucially involve alternatives, paired with matching strategies (Walsh & Johnson-Laird 2004) or with question-answer dynamics (Koralus & Mascarenhas 2013). Our results constitute further steps toward convergence between theories and methodologies in natural language semantics and the psychology of reasoning.