The Adaptive Toolbox framework specifies heuristics for choice and categorisation that search through cues in previously learned orders (Gigerenzer & Todd, 1999). We examined the learning of three cue parameters defining different orders: discrimination rate (DR) (the probability that a cue points to a unique choice), validity (the probability of correct choice given that a cue discriminates), and success (the probability of correct choice). Success orderings are identical to those by expected information gain (Klayman & Ha, 1987). In two experiments, participants made choices in real-world environments with objective outcome criteria. Participant ratings indicated some appropriate parameter learning when the relevant cue parameter values were highly dispersed. Rated orders of cue validity and DR were less distinct than the objective orders—learning one parameter may be biased towards success by variation in the other. Success ratings capture the variation in validity and DR as well as participants' perception of these parameters.

Theories of analogical reasoning have viewed relational structure as the dominant determinant of analogical mapping and inference, while assigning lesser importance to similarity between individual objects. An experiment is reported in which these two sources of constraints on analogy are placed in competition under conditions of high relational complexity. Results demonstrate equal importance for relational structure and object similarity, both in analogical mapping and in inference generation. The human data were successfully simulated using a computational analogy model (LISA) that treats both relational correspondences and object similarity as soft constraints that operate within a limited-capacity working memory; but not with a model (SME) that treats relational structure as pre-eminent.

Intuitive predictions and judgements under uncertainty are often mediated by judgemental heuristics that sometimes lead to biases. Our micro-developmental study suggests that a presumption of rationality is justified for adult subjects, in so far as their systematic judgemental biases appear to be due to a specific executive-inhibition failure in working memory, and not necessarily to a lack of understanding of the fundamental principles of probability. This hypothesis was tested using an experimental procedure in which 60 adult subjects were trained to inhibit the classical conjunction bias on a frequency judgement task derived from Tversky and Kahneman's work. Pre- and post-test performance was assessed via a probability judgement task. The data indicated a training effect, suggesting that subjects traditionally labelled as “irrational” with respect to the classical rules of inductive reasoning are in fact “inefficient inhibitors”. These findings are discussed in terms of a polymorphous view of rationality.

This research examined choice behaviour and probability judgement in a counterintuitive reasoning problem called the Monty Hall problem (MHP). In Experiments 1 and 2 we examined whether learning from a simulated card game similar to the MHP affected how people solved the MHP. Results indicated that the experience with the card game affected participants' choice behaviour, in that participants selected to switch in the MHP. However, it did not affect their understanding of the objective probabilities. This suggests that there is dissociation between implicit knowledge gained from the task and the explicit understanding as to why switching was the best strategy. In Experiment 3, the number of prizes and doors were manipulated to examine how participants construed the problem space of the MHP. Results revealed that participants partition the probability judgement to reflect the number of prizes over the number of unopened doors.

This paper describes Peirce's systems of logic diagrams, focusing on the so-called ''existential'' graphs, which are equivalent to the first-order predicate calculus. It analyses their implications for the nature of mental representations, particularly mental models with which they have many characteristics in common. The graphs are intended to be iconic, i.e., to have a structure analogous to the structure of what they represent. They have emergent logical consequences and a single graph can capture all the different ways in which a possibility can occur. Mental models share these properties. But, as the graphs show, certain aspects of propositions cannot be represented in an iconic or visualisable way. They include negation, and the representation of possibilities qua possibilities, which both require representations that do not depend on a perceptual modality. Peirce took his graphs to reveal the fundamental operations of reasoning, and the paper concludes with an analysis of different hypotheses about these operations.

(2000). Ecological rationality and its contents. Thinking & Reasoning: Vol. 6, No. 4, pp. 375-384.

This paper reports three studies of temporal reasoning. A problem of the following sort, where the letters denote common everyday events: A happens before B. C happens before B. D happens while B. E happens while C. What is the relation between D and E? calls for at least two alternative models to be constructed in order to give the right answer for the right reason (D happens after E). However, the first premise is irrelevant to this answer, and so if reasoners were to ignore it, then they would need to construct only one model. Experiment 1 showed that one-model problems were answered faster and more accurately than multiple-model problems. When the question preceded the premises in the statement of the multiple-model problems there was a slight tendency for the latencies of response to speed up in the predicted way. Experiment 2 modified the procedure, in part by using practice problems with many irrelevant premises, so that reasoners might grasp the advantage of ignoring them. Its results showed that when the premises preceded the question, the multiple-model problems were significantly harder than one-model problems. But when the question was presented first, the difference was significantly reduced in line with the theory's prediction. Experiment 3 used only problems with valid conclusions (i.e., one-model problems and multiple-model problems), and so the construction of multiple models was never necessary. However, there was still a significant difference between one-model problems and multiple-model problems.

Holyoak and Cheng's (1995) account of Wason's (1966) selection task was evaluated by testing participants' recognition memory for the rule. To accommodate the finding that participants' selections are systematically influenced by manipulating their perspective on the rule to be tested, Holyoak and Cheng put forward a development of Pragmatic Reasoning Schema (PRS) theory, according to which the rule being tested is mapped onto different schematic rules depending on the perspective taken. The instantiated schema then becomes the basis for reasoning, and the different schemas encourage the selection of different cases. We hypothesised that if participants interpret the rule by instantiating a particular schema, then they should falsely recognise a sentence corresponding to the instantiated schema a short time after performing the task. An experimental test provided limited support for this hypothesis.

The ratio-bias (RB) phenomenon refers to the perceived likelihood of a low-probability event as greater when it is presented in the form of larger (e.g. 10-in-100) rather than smaller (e.g. 1-in-10) numbers. According to cognitive-experiential self-theory (CEST), the RB effect in a game of chance in a win condition, in which drawing a red jellybean is rewarded, can be accounted for by two facets of concrete thinking, the greater comprehension (at the intuitive-experiential level) of single numbers than of ratios, and of smaller than of larger numbers. In a lose condition, in which drawing a red jellybean is punished, the assumption of a third facet of concrete thinking, the “affirmative-representation principle”, is necessary, as many participants reverse their focus of attention from the undesirable red to the desirable white jellybeans. Results supported the CEST explanation of the RB effect by demonstrating a predicted negative linear relation between the magnitude of the RB effect and the magnitude of the probability-ratios in the win condition and a positive linear relation in the lose condition. Support was also found for the associative principle of experiential processing.

Sequences of numbers representing prior resource size were presented to participants in a common-pool resource dilemma. The numbers were sampled from uniform probability distributions with either a low variance (low resource uncertainty) or a high variance (high resource uncertainty). Presentations were both sequential and simultaneous. Three groups of 16 undergraduates either estimated the size of the resource when it did not represent value to them; requested an amount from the resource, identified with a sum of money, when the outcome of the requests only depended on resource size; or requested from the resource (sum of money) when the outcome of the requests depended on both resource size and how much others in a group requested. In support of an individual outcome-desirability bias due to selective recall of the number sequences, after sequential presentation larger requests were observed when resource uncertainty was high than when it was low. No effects of resource uncertainty or presentation were found on the estimates of resource size. Whether or not the outcome of the requests depended on others' requests made little difference.