Rationality and the experimental study of reasoning

A survey of the results obtained during the past three decades in some of the most widely used tasks and paradigms in the experimental study of reasoning is presented. It is shown that, at first sight, human performance suffers from serious shortcomings. However, after the problems of communication between experimenter and subject are taken into account, which leads to clarify the subject's representation of the tasks, one observes a better performance, although still far from perfect. Current theories of reasoning, of which the two most prominent are very briefly outlined, agree in identifying the load in working memory as the main source of limitation in performance. Finally, a recent view on human rationality prompted by the foregoing results is described

Not only base rates are neglected in the Engineer-Lawyer problem: an investigation of reasoners' underutilization of complementarity.

International audienceThe standard Engineer-Lawyer problem (Kahneman & Tversky, 1973) points to the failure of reasoners to integrate mentioned base-rate information in arriving at likelihood estimates. Research in this area nevertheless has presupposed that participants respect complementarity (i.e., participants ensure that competing estimates add up to 100%). A survey of the literature leads us to doubt this pre-supposition. We propose that the participants' non-normative performance on the standard Engineer-Lawyer problem reflects a reluctance to view the task probabilistically and that normative responses become more prominent as probabilistic aspects of the task do. In the present experiments, we manipulated two kinds of probabilistic cues and determined the extent to which (1) base rates were integrated and (2) the complementarity constraint was respected. In Experiment 1, six versions of an Engineer-Lawyer-type problem (that varied three levels of cue to complementarity and two base rates) were presented. The results showed that base-rate integration increased as cues to complementary did. Experiment 2 confirmed that Gigerenzer, Hell, and Blank's (1988) random-draw paradigm facilitates base-rate integration; a second measure revealed that it also prompts respect for complementarity. In Experiment 3, we replicated two of our main findings in one procedure while controlling for the potential influence of extraneous task features. We discuss approaches that describe how probabilistic cues might prompt normative responding

Uncertainty and the de Finettitables

International audienceThe new paradigm in the psychology of reasoning adopts a Bayesian, or prob-abilistic, model for studying human reasoning. Contrary to the traditional binary approach based on truth functional logic, with its binary values of truth and falsity, a third value that represents uncertainty can be introduced in the new paradigm. A variety of three-valued truth table systems are available in the formal literature, including one proposed by de Finetti. We examine the descriptive adequacy of these systems for natural language indicative condi-tionals and bets on conditionals. Within our framework the so-called " defective " truth table, in which participants choose a third value when the antecedent of the indicative conditional is false, becomes a coherent response. We show that only de Finetti's system has a good descriptive fit when uncertainty is the third value. The new Bayesian, or probabilistic, paradigm in the psychology of reasoning (Oaksford & Chater, 2007, 2009; Over, 2009; Pfeifer & Kleiter, 2010) implies a close parallel relationship between assertions of the indicative conditional of natural language, if A then C, and other uses of conditionals, particularly bets on conditionals, I bet that if A then B. Politzer, Over, and Baratgin (2010) explain how this predicted relation goes back to Ramsey (1926/1990, 1929/1990) and de Finetti (1936/1995, 1937/1964) and provide experimental evidence that this parallel relation exists (see also Baratgin, Over, & Politzer, in press). Financial support for this work was provided by the French ANR agency under grant ANR Chorus 2011 (project BTAFDOC). We would like to thank Paul Egr e, Jean-Louis Stilgenbauer, and Tatsuji Takahashi for much discussion and other help in our research. We also thank Shira Elqayam, Jean-François Bonnefon, and two anonymous reviewers

Bayesian reasoning with ifs and ands and ors

The Bayesian approach to the psychology of reasoning generalizes binary logic, extending the binary concept of consistency to that of coherence, and allowing the study of deductive reasoning from uncertain premises. Studies in judgment and decision making have found that people’s probability judgments can fail to be coherent. We investigated people’s coherence further for judgments about conjunctions, disjunctions and conditionals, and asked whether their coherence would increase when they were given the explicit task of drawing inferences. Participants gave confidence judgments about a list of separate statements (the statements group) or the statements grouped as explicit inferences (the inferences group). Their responses were generally coherent at above chance levels for all the inferences investigated, regardless of the presence of an explicit inference task. An exception was that they were incoherent in the context known to cause the conjunction fallacy, and remained so even when they were given an explicit inference. The participants were coherent under the assumption that they interpreted the natural language conditional as it is represented in Bayesian accounts of conditional reasoning, but they were incoherent under the assumption that they interpreted the natural language conditional as the material conditional of elementary binary logic. Our results provide further support for the descriptive adequacy of Bayesian reasoning principles in the study of deduction under uncertainty

Regret and the rationality of choices

Regret helps to optimize decision behaviour. It can be defined as a rational emotion. Several recent neurobiological studies have confirmed the interface between emotion and cognition at which regret is located and documented its role in decision behaviour. These data give credibility to the incorporation of regret in decision theory that had been proposed by economists in the 1980s. However, finer distinctions are required in order to get a better grasp of how regret and behaviour influence each other. Regret can be defined as a predictive error signal but this signal does not necessarily transpose into a decision-weight influencing behaviour. Clinical studies on several types of patients show that the processing of an error signal and its influence on subsequent behaviour can be dissociated. We propose a general understanding of how regret and decision-making are connected in terms of regret being modulated by rational antecedents of choice. Regret and the modification of behaviour on its basis will depend on the criteria of rationality involved in decision-making. We indicate current and prospective lines of research in order to refine our views on how regret contributes to optimal decision-making

Developing Sustainable Process in Water Economy Using Social Media

International audienceThe main idea developed here is how to involve people to promote a new behavior to economize water as supported by the local authorities process. Usually, the population is affected by the cities policies when they are subject to fines related to high water use during times of crisis. Then the local authorities impose solutions without consultations of concerned communities. This top-down process is often considered as imposed by the mayor or the local authority and may lead to bad feeling by the population and is not corresponding to a new societal behavior in the social web era. We will suggest a new way to involve the population using the social media as a new approach to imply them in this process. This information can be conveyed and shared with the public in such way to support mayor or authorities policies. In other way we will propose a new approach using social media processes as a node in the first hand to encourage the population to participate to the debate and to fit a new solution encouraging all population to get part of the policies adopted based on a bayesian approach

Centering and the meaning of conditionals

The centering inference - p & q, therefore if p then q - is important in reasoning research because it is logically valid for some accounts of conditionals (e. g. the material and the probability conditionals), but not for others (e. g. the inferential conditional, according to which a conditional is true if and only if there is an inferential connection between p and q). We tested participants' acceptance of centering compared to valid and invalid inferences not containing conditionals, varying the presence of an inferential connection and of a common topic of discourse between p and q. Participants' acceptance of centering was more similar to valid inferences than to invalid inferences, and there was no reliable effect of a connection between p and q. Acceptance rates were higher when there was a common topic of discourse, independently of the type of inference. The findings support the probability conditional account

Cycles of maximin and utilitarian policies under the veil of ignorance

International audienc