Strategies for hypothesis testing in scientific investigation and everyday reasoning have interested both psychologists and philosophers. A number of these scholars stress the importance of disconfir. marion in reasoning and suggest that people are instead prone to a general deleterious "confirmation bias" In particula~ it is suggested that people tend to test those cases that have the best chance of verifying current beliefs rather than those that have the best chance of falsifying them. We show, howeve~ that many phenomena labeled "confirmation bias" are better understood in terms of a general positive test strate~. With this strategy, there is a tendency to test cases that are expected (or known) to have the property of interest rather than those expected (or known) to lack that property. This strategy is not equivalent to confirmation bias in the first sense; we show that the positive test strategy can be a very good heuristic for determining the truth or falsity of a hypothesis under realistic conditions~ It can, howeve~ lead to systematic errors or inefficiencies. The appropriateness of human hypotheses-testing strategies and prescriptions about optimal strategies must he understood in terms of the interaction between the strategy and the task at hand.

/pdf/confirmation-disconfirmation-and-information-in-hypothesis-8ag5boxfnh.pdf

Confirmation, Disconfirmation, and Information in Hypothesis Testing

http://cs.northwestern.edu/~paritosh/papers/sketch-to-models/klahr-dunbar-dual-space-search-cogsci-1988.pdf

Dual space search during scientific reasoning

http://sbnec.org.br/gene/Limon%202001.pdf

On the cognitive conflict as an instructional strategy for conceptual change: a critical appraisal

A widely advocated idea in education is that people learn better when the flow of experience is under their control (i.e., learning is self-directed). However, the reasons why volitional control might result in superior acquisition and the limits to such advantages remain poorly understood. In this article, we review the issue from both a cognitive and computational perspective. On the cognitive side, self-directed learning allows individuals to focus effort on useful information they do not yet possess, can expose information that is inaccessible via passive observation, and may enhance the encoding and retention of materials. On the computational side, the development of efficient “active learning” algorithms that can select their own training data is an emerging research topic in machine learning. This review argues that recent advances in these related fields may offer a fresh theoretical perspective on how people gather information to support their own learning.

/pdf/self-directed-learning-a-cognitive-and-computational-389dc3hrgw.pdf

Self-Directed Learning: A Cognitive and Computational Perspective.

Background: Errors in clinical reasoning occur in most cases in which the diagnosis is missed, delayed or wrong. The goal of this review was to identify interventions that might reduce the likelihood of these cognitive errors. Design: We searched PubMed and other medical and non-medical databases and identified additional literature through references from the initial data set and suggestions from subject matter experts. Articles were included if they either suggested a possible intervention or formally evaluated an intervention and excluded if they focused solely on improving diagnostic tests or provider satisfaction. Results: We identified 141 articles for full review, 42 reporting tested interventions to reduce the likelihood of cognitive errors, 100 containing suggestions, and one article with both suggested and tested interventions. Articles were classified into three

/pdf/cognitive-interventions-to-reduce-diagnostic-error-a-3hyk9zzl0t.pdf

Cognitive interventions to reduce diagnostic error: a narrative review

Attempts to instruct subjects to falsify on inference tasks designed to model scientific problem-solving have indicated that, in most cases, falsification does not lead to improved performance. The only study in which instructions to falsify did improve performance was done with groups, using a novel inference task. The present study is an attempt to replicate the success of falsification in the group study with subjects run individually on an inference task that has been used extensively in the literature: Wason's 2–4–6 problem. Each subject was run in one of three strategy conditions: confirmatory, disconfirmatory or control (no-strategy). Results indicated that subjects in the disconfirmatory condition solved the 2–4–6 problem significantly more often than subjects in other conditions. The superior performance of disconfirmatory subjects was explained by the fact that they deliberately sought and obtained significantly more falsificatory information than subjects in other conditions. The critical diffe...

A Comparison of Disconfirmatory, Confirmatory and Control Strategies on Wason's 2–4–6 Task:

This paper reports two experiments in which subjects worked to solve a more difficult version of Wason's 2–4–6 task: instead of the usual “numbers must ascend in order of magnitude” rule, a more general rule, “the three numbers must be different”, was used. The first experiment established that instructing subjects to disconfirm on the “three different numbers” did not significantly improve their performance, as compared with confirmatory and control groups. Disconfirmatory subjects did try to propose more triples at variance with their hypotheses but were unable to obtain the necessary disconfirmatory information. To help subjects represent the task in a way that facilitated disconfirmation, the second experiment utilized a procedure in which subjects were told that they were looking for two rules, Dax and Med–the Dax rule corresponding to “three different numbers” and the Med rule to its complement, i.e. two or more numbers the same. Of subjects in the Dax–Med condition, 88% solve the rule, as opposed t...

Disconfirmation and dual hypotheses on a more difficult version of wason's 2–4–6 task

This paper presents three experiments designed to test Karl Popper's idea that scientists should try to falsify, or disconfirm, their hypotheses instead of verifying them. Previous studies indicate that subjects trained to falsify do no better on scientific problem-solving tasks than subjects trained to confirm. But these studies have all focused on individual subjects. Scientists frequently work in groups. To see how groups disconfirm, subjects in the first two studies reported here were run in groups of four. They were asked to solve a series of related problems based on ‘New Eleusis’, a task designed to model the ‘search for truth’.



In the first study, group members were either allowed to interact or told to work separately. This variable was crossed with a strategy (disconfirmatory vs. confirmatory) variable. There were no significant differences.



In the second study, only interacting groups were run, some methodological problems with the strategy variable were cleared up and a third strategy that combined elements of confirmation and disconfirmation was added. Disconfirmatory groups solved significantly more problems (72 per cent) than confirmatory (25 per cent) with combined (50 per cent) falling in between. Disconfirmatory groups also made significantly more attempts to falsify their hypotheses.



To see if the same results would hold for individuals working on a different task, subjects were trained to disconfirm, confirm or use no strategy on Wason's 2–4-6 task. Disconfirmatory subjects were again significantly more successful. The overall results suggest that a disconfirmatory strategy is superior for both groups and individuals on tasks that simulate scientific problems. Reasons why this effect was obtained in the present research but not in earlier studies are discussed.

Margaret E. Gorman

Papers

A Comparison of Disconfirmatory, Confirmatory and Control Strategies on Wason's 2–4–6 Task:

Disconfirmation and dual hypotheses on a more difficult version of wason's 2–4–6 task

How disconfirmatory, confirmatory and combined strategies affect group problem solving