On the problems of interpreting reasoning data: Logical and psychological approaches

Toward a Statistical Theory of Reasoning

It is argued that the observed variability of responding in reasoning tasks might usefully be described by mathematical models based on stochastic processes. The data of a number of experiments employing Wason's selection task are reanalysed and it is shown that selection probabilities of individual cards are statistically independent. This is consistent with a class of simple stochastic models and renders conventional “insight” explanations of the data unparsi-monious.

A provisional stochastic model is formulated and subjected to a limited parametric test with reasonably satisfactory results. Some general directions for future research along these lines are suggested.

Effects of Content on Inclusive Disjunction Reasoning

An experiment is reported which establishes that inclusive disjunction arguments embedded in concrete content are not always easier to reason with than those involving abstract content. The subjects had to assess conclusions drawn from pairs of premises such as “Either Joan is intelligent or she is rich (or both); Joan is intelligent” or “Either Joan is intelligent or she is rich (or both); Joan is not intelligent”. The terms in the disjunctive premise were varied systematically across three content dimensions (i.e. compatible, abstract and contradictory). An analysis of variance revealed significant differences according to both principle of inference and type of content, and a significant interaction between these factors. The results demonstrated that semantically incompatible premise content had a marked influence on comprehension of inclusive disjunction reasoning schemes. The response patterns suggest that these reasoning schemes invited erroneous judgments based on other logical connectives.

Formulation and Experimental Verification of Models in Propositional Reasoning

In Evans (1977) an experiment of Evans and Lynch (1973) based on Wason's selection task is re-analysed. We reformulated the model proposed by Evans as a state model and extended it to a new model by means of which the data of Evans and Lynch (1973), of Manktelow and Evans (1979), and of our own experiments can be explained. The new model is based on a falsification state, a verification state and a matching state.

Linguistic Factors in Conditional Reasoning

An experiment is reported which demonstrates the influence of three cognitive variables on adults' abilities to reason with conditional arguments embedded in either causal-temporal or class inclusion content. The three variables are the linguistic form of the conditional rule, the principle of conditional reasoning, and the order of the components in the conditional rule. The results showed considerable similarity in the effects of these factors for the two types of concrete content, but some interesting differences were found. The findings are discussed in relation to the results of recent investigations which involved abstract content and/or other deductive reasoning paradigms.

Linguistic Factors in Reasoning

An experiment is reported which attempts to demonstrate the effects of manipulating two linguistic variables on a propositional reasoning task, one relating to the linguistic form of the logical rule, and the other to the presence and absence of negative components. The results are discussed in relation to Evans' (1972a) distinction between interpretational and operational factors in reasoning. Problems arising from the application of this distinction are discussed in detail.

Linguistic and Psychometric Factors in Propositional Reasoning

An experiment is reported which demonstrates the effects of linguistic and psychometric factors on adults’ performance on a propositional reasoning task. The three linguistic factors were the semantic content in which the logical rule was embedded, the linguistic form of the logical rule, and the polarity of the major premise of the logical arguments. The two psychometric factors were the mode of response and the order of presentation of the different types of content. The results showed that the linguistic factors had a pronounced effect on adults’ propositional reasoning abilities, whereas the influence of the psychometric factors was negligible. These findings are discussed in relation to operational and interpretational factors in reasoning.

Confirmation Bias: A Ubiquitous Phenomenon in Many Guises

Confirmation bias, as the term is typically used in the psychological literature, connotes the seeking or interpreting of evidence in ways that are partial to existing beliefs, expectations, or a hypothesis in hand. The author reviews evidence of such a bias in a variety of guises and gives examples of its operation in several practical contexts. Possible explanations are considered, and the question of its utility or disutility is discussed.

Transfer of conditional reasoning: effects of explanations and initial problem types

Transfer of reasoning on Wason's (1966) selection task was explored in three experiments. Experiment 1 tested the effects of problem explanations and verbalization instructions on transfer from abstract or thematic problems to abstract problems. Explanations facilitated transfer only when the initial problems were abstract; verbalization did not produce transfer between problems. Experiment 2 explored the effects of problem similarity and explanations on transfer between problems. Although transfer occurred following explanations, no effect of similarity was found for thematic problems. In both of these experiments, the thematic effect (Wason & Shapiro, 1971) was observed. Experiment 3 examined the effects of explanations to abstract or thematic problems on transfer to subsequent abstract or thematic problems. Transfer of reasoning occurred from both initial problem types, particularly to problems of the same type; however, transfer occurred to a greater extent from abstract problems than from thematic problems. The results are discussed in terms of problem similarity and Cheng and Holyoak's (1985) pragmatic reasoning schema hypothesis.