An availability bias in professional judgment

When branches of a fault tree are pruned, subjects do not fully transfer the probability of those branches to the ‘all other’ category. This underestimation of the catch-all probability has been interpreted as an ‘out of sight, out of mind’ form of the availability bias. The present work replicates this underestimation bias with professional managers. It then demonstrates the effectiveness of a corrective tactic, extending the tree by generating additional causes, and also reveals that more easily retrieved short-term causes dominate the generation process. These results do not differ across managers' culture, education or experience. After evaluating such alternative explanations as category redefinition, we conclude that availability is a major cause, though possibly not the sole cause, of the underestimation bias.     

Debiasing of Pessimistic Judgments Associated with Anxiety: A Test of the Availability Heuristic

This investigation directly tested the Consider-An-Alternative debiasing procedure and the reduction of pessimistic threat-related judgments associated with anxiety. Two separate generation interventions were included to test the availability heuristic as a possible explanation of the debiasing effect. Participants were randomly assigned to one of three interventions and probability estimates of future threat-related events were completed in a repeated measures experimental design. Level of trait anxiety was measured to assign participants to “normal” and highly anxious groups. The data were analyzed in a 3 × 2 × 2 mixed factorial repeated measures ANOVA. The results found that only the short debiasing intervention showed a significant reduction of pessimistic judgments in comparison to the control group. The results were interpreted as supporting the availability heuristic as an explanation of the debiasing effect. Further analysis also suggested that the content of recall may be as important to the debiasing effect as ease of recall.     

Perspectives on prediction: Does third-person imagery improve task completion estimates?

People typically underestimate the time necessary to complete their tasks. According to the planning fallacy model of optimistic time predictions, this underestimation occurs because people focus on developing a specific plan for the current task and neglect the implications of past failures to meet similar deadlines. We extend the classic planning fallacy model by proposing that a phenomenal quality of mental imagery – the visual perspective that is adopted – may moderate the optimistic prediction bias. Consistent with this proposal, participants in four studies predicted longer completion times, and thus were less prone to bias, when they imagined an upcoming task from the third-person rather than first-person perspective. Third-person imagery reduced people’s focus on optimistic plans, increased their focus on potential obstacles, and decreased the impact of task-relevant motives on prediction. The findings suggest that third-person imagery helps individuals generate more realistic predictions by reducing cognitive and motivational processes that typically contribute to bias.     

Context affects the interpretation of low but not high numerical probabilities: A hypothesis testing account of subjective probability

Low numerical probabilities tend to be directionally ambiguous, meaning they can be interpreted either positively, suggesting the occurrence of the target event, or negatively, suggesting its non-occurrence. High numerical probabilities, however, are typically interpreted positively. We argue that the greater directional ambiguity of low numerical probabilities may make them more susceptible than high probabilities to contextual influences. Results from five experiments supported this premise, with perceived base rate affecting the interpretation of an event’s numerical posterior probability more when it was low than high. The effect is consistent with a confirmatory hypothesis testing process, with the relevant perceived base rate suggesting the directional hypothesis which people then test in a confirmatory manner.     

Speed reductions and judgments of travel time loss: Biases and debiasing

Priority decisions concerning maintenance or reconstruction of roads are made with the aim of road improvements with as little traffic disturbance and time loss as possible. However, it cannot be avoided that speed will be reduced and travel time increased during the time of construction. The present study shows how intuitive judgments of travel time losses are biased in a way similar to the times saving bias (Svenson, 2008), but not perfectly corresponding to that bias. This means that when speed is decreased from a slow speed <50 km/h, the time loss is underestimated and when speed is decreased from a high speed >80 km/h it is overestimated. Also, drivers, politicians and policy makers who do not make exact calculations are likely victims of the time loss bias. The time loss bias was weakened but not eliminated by a debiasing instruction including mathematical computations of travel times. When driving speed restrictions are implemented, in particular on fast motorways, it is necessary to consider and counteract the time loss bias and inform the public. This can be done, for example, in communications about travel time facts, by information in driver training and by mounting temporary road signs informing about the average travel time prolongation due to a road work.     

Alleviating inflation of conditional predictions

Previous studies indicated that conditional predictions—the assessed probability that a certain outcome will occur given a certain condition—tend to be markedly inflated. Five experiments tested the effects of manipulations that were expected to alleviate this inflation by inducing participants to engage in analytic processing. Rewarding participants for accurate predictions proved ineffective. A training procedure in which participants assessed the likelihood of each of several outcomes before assessing the probability of a target outcome was partly effective in reducing overestimation. Most effective was the requirement to work in dyads and to come to an agreement about the assessed likelihood. Working in dyads helped alleviate prediction inflation even after participants made their individual predictions alone, and its debiasing effect also transferred to the estimates that were made individually on a new set of stimuli. The results were discussed in terms of the factors that make prediction inflation resistant to change.     

Learning From Peers’ Eye Movements in the Absence of Expert Guidance: A Proof of Concept Using Laboratory Stock Trading,Eye Tracking,and Machine Learning

Existing research shows that people can improve their decision skills by learning what experts paid attention to when faced with the same problem. However, in domains like financial education, effective instruction requires frequent, personalized feedback given at the point of decision, which makes it time‐consuming for experts to provide and thus, prohibitively costly. We address this by demonstrating an automated feedback mechanism that allows amateur decision‐makers to learn what information to attend to from one another, rather than from an expert. In the first experiment, eye movements of N = 100 subjects were recorded while they repeatedly performed a standard behavioral finance investment task. Consistent with previous studies, we found that a significant proportion of subjects were affected by decision bias. In the second experiment, a different group of N = 100 subjects faced the same task but, after each choice, they received individual, machine learning‐generated feedback on whether their pre‐decision eye movements resembled those made by Experiment 1 subjects prior to good decisions. As a result, Experiment 2 subjects learned to analyze information similarly to their successful peers, which in turn reduced their decision bias. Furthermore, subjects with low Cognitive Reflection Test scores gained more from the proposed form of process feedback than from standard behavioral feedback based on decision outcomes.     

Selective versus comparative processing

Simonson et al. (forthcoming) propose a new theory of comparison selection that explains which particular alternatives will be considered in a wide variety of judgment and choice tasks. Comparison selection depends on the latitude of acceptance, comparison fluency, and the interaction between these factors. Importantly, these factors integrate a wide variety of seemingly unrelated variables, and the theory is useful for generating novel hypotheses. However, because comparative processing occurs relatively infrequently, it is important to take a step back and specify the conditions under which comparative processing is likely to occur. Comparative processing is likely only when the motivation and the opportunity to process information carefully are high, when consumers lack knowledge about distributional standards, or when stimulus-based judgment is likely. The two types of processes have different antecedents, consequences, and implications for debiasing.     

Activating a mental simulation mind-set through generation of alternatives: Implications for debiasing in related and unrelated domains

Encouraging people to consider multiple alternatives appears to be a useful debiasing technique for reducing many biases (explanation, hindsight, and overconfidence), if the generation of alternatives is experienced as easy. The present research tests whether these alternative generation procedures induce a mental simulation mind-set (cf. Galinsky & Moskowitz, 2000), such that debiasing in one domain transfers to debias judgments in unrelated domains. The results indeed demonstrated that easy alternative generation tasks not only debiased judgments in the same domain but also generalized to debias judgments in unrelated domains, provided that participants were low in the need for structure. The alternative generation tasks (even when they were easy to perform) showed no evidence of activating a mental simulation mind-set in individuals high in need for structure, as these individuals displayed no transfer effects. Implications of the results for understanding the role of the need for structure, ease of generation, and mental simulation mind-set activation for debiasing are discussed.