(Italian translation: Le consulenze sull' AIDS per persone a basso rischio. In <i>La dimensione cognitiva dell' errore in medicina,<i/> pp. 185-203, by V. Crupi, G. Gensini, & M. Motterlini, Eds., 2006, Milan: Franco Angeli)

This study addresses the counselling of heterosexual men with low-risk behaviour who, voluntarily or involuntarily, take an HIV test. If such a man tests positive, the chance that he is infected can be as low as 50%. We study what information counsellors communicate to clients concerning the meaning of a positive test and whether they communicate this information in a way the client can understand. To get realistic data, one of us visited as a client 20 public health centers in Germany to take 20 counselling sessions and HIV tests. A majority of the counsellors explained that false positives do not occur, and half of the counsellors told the client that if he tests positive, it is 100% certain that he is infected with the virus. Counsellors communicated numerical information in terms of probabilities rather than absolute frequencies, became confused, and were inconsistent. Based on experimental evidence, we propose a simple method that counsellors can learn to communicate risks in a more effective way

Modeling and Aiding Intuition: Introduction to the Commentary Section

This section of JARMAC includes a series of commentaries on articles published in the September, 2015, special issue of JARMAC: "Modeling and aiding intuition in organizational decision making" (Marewski &amp; Hoffrage, 2015). The commentaries focus on research programs such as naturalistic decision making, heuristics-and-biases, ACT-R, and CLARION. They feature topics ranging from evolution to decision styles. In this introduction, we provide a brief overview of those contributions, alongside with concluding words on this project of pulling together multiple and very different strands of research on intuition

Gesellschaftliche Perspektiven von Risikowahrnehmung und Risikokompetenz

Risiken innerhalb der Medizin sind nicht bloß durch objektivierbare Eigenschaften von Therapien fassbar, sondern in erheblichem Maße durch individuelle und gesellschaftliche Werte geprägt. Individuen streben gleichermaßen nach Freiheit und Sicherheit - im medizinischen Kontext wird dem durch partizipative Entscheidungsmodelle einerseits und Verschärfungen der Regularien im Arzneimittelsektor andererseits Rechnung getragen. Die mediale Berichterstattung über Risiken im Gesundheitsbereich findet im Spannungsfeld zwischen Aufklärung und wirtschaftlichen Interessen statt, was insbesondere eine rationale Diskussion über unerwartete Risiken (z.B. in der Naturheilkunde) erschwert. Es gilt daher eine Informationskultur zu schaffen, die es erlaubt, echte von weniger ausgeprägten Risiken zu unterscheiden

Toward an ecological analysis of Bayesian inferences: How task characteristics influence responses

In research on Bayesian inferences, the specific tasks, with their narratives and characteristics, are typically seen as exchangeable vehicles that merely transport the structure of the problem to research participants. In the present paper, we explore whether, and possibly how, task characteristics that are usually ignored influence participants' responses in these tasks. We focus on both quantitative dimensions of the tasks, such as their base rates, hit rates, and false-alarm rates, as well as qualitative characteristics, such as whether the task involves a norm violation or not, whether the stakes are high or low, and whether the focus is on the individual case or on the numbers. Using a data set of 19 different tasks presented to 500 different participants who provided a total of 1,773 responses, we analyze these responses in two ways: first, on the level of the numerical estimates themselves, and second, on the level of various response strategies, Bayesian and non-Bayesian, that might have produced the estimates. We identified various contingencies, and most of the task characteristics had an influence on participants' responses. Typically, this influence has been stronger when the numerical information in the tasks was presented in terms of probabilities or percentages, compared to natural frequencies - and this effect cannot be fully explained by a higher proportion of Bayesian responses when natural frequencies were used. One characteristic that did not seem to influence participants' response strategy was the numerical value of the Bayesian solution itself. Our exploratory study is a first step toward an ecological analysis of Bayesian inferences, and highlights new avenues for future research

Chances and risks in medical risk communication

Communication between physicians and patients in everyday life is marked by a number of disruptive factors. Apart from specific interests, mistakes, and misunderstandings on both sides, there are main factors that contribute to the risk in risk communication. Using the example of mammography screening, the current work demonstrates how the meaning of test results and the informative value of measures taken to reduce risk are often misunderstood. Finally, the current work provides examples of successful risk communication

Unveiling the Lady in Black: Modeling and aiding intuition

The cognitive and decision science literature on modeling and aiding intuitions in organizations is rich, but segregated. This special issue offers a sample of that literature, stimulating exchange and inspiring intuitions about intuition. A total of 16 articles bring together diverse approaches, such as naturalistic-decision-making, heuristics-and-biases, dual-processes, ACT-R, CLARION, Brunswikian, and Quantum-Probability-Theory, many of them co-authored by their founders. The articles cover computational models and verbal theories; experimental and observational work; laboratory and naturalistic research. Comprising various domains, such as consulting, investment, law, police, and morality, the articles relate intuition to implicit cognition, emotions, scope insensitivity, expertise, and representative experimental design. In this article, we map intuition across poles such as Enlightenment/Romanticism, reason/emotion, objectivity/subjectivity, inferences/qualia, Taylorism/universal scholarship, System 2/System 1, dichotomies/dialectics, and science/art. We discuss intuitions as inspirations, instincts, inferences, and insights. Finally, we review the contributions to this special issue, placing them into historical, philosophical, and societal contexts

Natural frequencies facilitate diagnostic inferences of managers

In Bayesian inference tasks, information about base rates as well as hit rate and false-alarm rate needs to be integrated according to Bayes' rule after the result of a diagnostic test became known. Numerous studies have found that presenting information in a Bayesian inference task in terms of natural frequencies leads to better performance compared to variants with information presented in terms of probabilities or percentages. Natural frequencies are the tallies in a natural sample in which hit rate and false-alarm rate are not normalized with respect to base rates. The present research replicates the beneficial effect of natural frequencies with four tasks from the domain of management, and with management students as well as experienced executives as participants. The percentage of Bayesian responses was almost twice as high when information was presented in natural frequencies compared to a presentation in terms of percentages. In contrast to most tasks previously studied, the majority of numerical responses were lower than the Bayesian solutions. Having heard of Bayes' rule prior to the study did not affect Bayesian performance. An implication of our work is that textbooks explaining Bayes' rule should teach how to represent information in terms of natural frequencies instead of how to plug probabilities or percentages into a formula

Ethical Blindness

Many models of (un)ethical decision making assume that people decide rationally and are in principle able to evaluate their decisions from a moral point of view. However, people might behave unethically without being aware of it. They are ethically blind. Adopting a sensemaking approach, we argue that ethical blindness results from a complex interplay between individual sensemaking activities and context factors

Picking profitable investments: The success of equal weighting in simulated venture capitalist decision making

Using computer simulation, we investigate the impact of different strategies on the financial performance of VCs. We compare simple heuristics such as equal weighting and fast and frugal trees with more complex machine learning and regression models and analyze the impact of three factors: VC learning, the statistical properties of the investment environment, and the amount of information available in a business plan. We demonstrate that the performance of decision strategies and the relative quality of decision outcomes change critically between environments in which different statistical relationships hold between information contained in business plans and the likelihood of financial success. The Equal Weighting strategy is competitive with more complex investment decision strategies and its performance is robust across environments. Learning only from those plans that the simulated VC invested in, drastically reduces the VC's potential to learn from experience. Lastly, the results confirm that decision strategies differ in respect to the impact of added information on the outcomes of decisions. Finally, we discuss real-world implications for the practice of VCs and research on VC decision making