Laura Macchi

Pragmatic Aspects of the Base-rate Fallacy

An investigation was made of the role played by verbal structure in the problems used to study the base-rate fallacy, which has traditionally been attributed to the role of heuristics (e.g. causality, specificity). It was hypothesized that elements of the verbal form of text problems led to a misunderstanding of the question or the specific information, rendering obscure the independence of the sets of data (specific information is obtained independently from the base rate). Nine texts were presented to various groups of subjects: four were taken from Tversky and Kahneman (1980) and used as controls; five were obtained by modifying the verbal form of the original in order to reveal or conceal the links between the sets of data. The percentage of base-rate fallacies was greatly reduced with texts in which the independence of the data was clear, regardless of the causality and specificity of the information they contained (which was not changed). This result suggests that there is a need to consider the rules of natural language in order to move towards a better understanding of observed phenomena.

Thinking About Low-Probability Events: An Exemplar Cuing Theory

The way people respond to the chance that an unlikely event will occur depends on how the event is described. We propose that people attach more weight to unlikely events when they can easily generate or imagine examples in which the event has occurred or will occur than when they cannot. We tested this idea in two experiments with mock jurors using written murder scenarios. The results suggested that jurors attach more weight to the defendants claim that an incriminating DNA match is merely coincidental when it is easy for them to imagine other individuals whose DNA would also match than when it is not easy for them to imagine such individuals. We manipulated the difficulty of imagining such examples by varying the description of the DNA-match statistic. Some of the variations that influenced the jurors were normatively irrelevant.

Reasoning and pragmatics

Language pragmatics is applied to analyse problem statements and instructions used in a few influential experimental tasks in the psychology of reasoning. This analysis aims to determine the interpretation of the task which the participant is likely to construct. It is applied to studies of deduction (where the interpretation of quantifiers and connectives is crucial) and to studies of inclusion judgment and probabilistic judgment. It is shown that the interpretation of the problem statements or even the representation of the task as a whole often turn out to differ from the experimenters assumptions. This has serious consequences for the validity of these experimental results and therefore for the claims about human irrationality based on them.

Pragmatic approach to decision making under uncertainty: The case of the disjunction effect

The disjunction effect (Tversky & Shafir, 1992) occurs when decision makers prefer option x (versus y) when knowing that event A occurs and also when knowing that event A does not occur, but they refuse x (or prefer y) when not knowing whether or not A occurs. This form of incoherence violates Savages (1954) sure-thing principle, one of the basic axioms of the rational theory of decision making. The phenomenon was attributed to a lack of clear reasons for accepting an option (x) when subjects are under uncertainty. Through a pragmatic analysis of the task and a consequent reformulation of it, we show that the effect does not depend on the presence of uncertainty, but on the introduction of non-relevant goals into the text problem, in both the well-known Gamble problem and the Hawaii problem.

Insight and creative thinking processes: Routine and special

In recent years there has been an upsurge of research aimed at removing the mystery from insight and creative problem solving. The present special issue reflects this expanding field. Overall the papers gathered here converge on a nuanced view of insight and creative thinking as arising from multiple processes that can yield surprising solutions through a mixture of “special” (automatic, unconscious and associative) Type 1 processes and “routine” (controlled, conscious and analytic) Type 2 processes.

The role of pragmatic rules in the conjunction fallacy

We here report the findings of our investigation into the validity of the “conjunction fallacy” (Tversky & Kahneman, 1983), bearing in mind the role of conversational rules. Our first experiment showed that subjects found a logically correct answer unacceptable when it implied a violation of the conversational rules.We argue that tautological questions, such as those which concern the relationship of inclusion between a class and its sub-class, violate conversational rules because they are not informative. In this sense, it is not understood that the question in a Linda-type problem involves a comparison between an inclusive and included class, but presumed that a different type of comparison is intended.Tautological questions (and, consequently, also their answers) do not become a matter of discussion except under certain specific conditions. Our second experiment showed that, providing the context was adequately marked (such as in the case of a rhetorical question), the conjunction fallacy disappears.In two further experiments, the implications of our view were compared with those of the other critical approaches to the heuristic programme: the classical pragmatic view (which we call logical complementarity) and the frequentist view.

Children’s acceptance of underinformative sentences: the case of some as a determiner

In recent literature there is unanimous agreement about childrens pragmatic competence in drawing scalar implicatures about some, if the task is made easy enough. However, children accept infelicitous some sentences more often than adults do. In general their acceptance is assumed to be synonymous with a logical interpretation of some as a quantifier. But in our view an overlap with some as a determiner in under-informative sentences cannot be ruled out, given the ambiguity of the experimental instructions and the attitude of trust by children in adults. Our study investigated this hypothesis with different experimental manipulations. We found that when the experimenters intentions are clear (Experiment 1, all/some order effect; Experiments 2 and 4, conditions 2 and 3), under-informative sentences are usually rejected; otherwise (Experiment 1, some/all order effect; Experiments 3 and 4, control condition) they are accepted. However, analysis of verbal protocols indicated that pragmatically infelicitous sentences are accepted, with some interpreted mostly as a determiner, irrespective of the function of some as a quantifier. Acceptance is not in itself synonymous with a logical interpretation of some as a quantifier.

When analytic thought is challenged by a misunderstanding

In our view, the way of thinking involved in insight problem solving is very close to the process involved in the understanding of an utterance, when a misunderstanding occurs. In this case, a more appropriate meaning has to be selected to resolve the misunderstanding (the “impasse”), the default interpretation (the “fixation”) has to be dropped in order to “restructure”, to grasp another meaning which appears more relevant to the context and the speakers intention. A new conception of unconscious, implicit thought emerges, informed by relevance. In this article we support our view with experimental evidence, focusing on how a misunderstanding is formed. We have explored two problems, in which a trivial arithmetical task is represented as an insight problem and vice versa. Studying how an insight problem is formed, and not just how it is solved, may well become an important topic in the contemporary debate on thought.

OVERVIEW ON DECISION MAKING

The systematic empirical study of judgement and decision making did not begin to emerge as a discipline in its own right until the 1960s, when there was an upsurge of interest in the broader and more general field of cognitive psychology that includes memory, thinking, problem solving, mental imagery and language.