The Hindsight Bias: The Role of the Availability Heuristic and Perceived Risk

The influence of outcome knowledge (Fischhoff, 1975) and the availability heuristic (Tversky & Kahneman, 1974) on judgments of perceived risk was explored here. This study found that subjects were capable of making relatively appropriate probability estimates for disease, accident, and homicide in foresight, but they made relatively biased estimated in hindsight. The results suggest that hindsight information activates the use of the availability heuristic on peoples' probability estimates of certain misfortune.     

Perceived Event Frequency and the Optimistic Bias: Evidence for a Two-Process Model of Personal Risk Judgments

People often judge themselves to be at lower risk for various negative life events than are their peers. The two empirical studies presented here show that the magnitude of this optimistic bias can be either negatively or positively related to the perceived frequency of the event, depending on whether people judge their own risk relative to that of an average peer (make comparative risk judgments) or judge their own and an average peer's risk separately (make absolute risk judgments). A new two-process model is presented to account for these results. The model combines a better-than-average heuristic with elements of the singular target-focused and singular- distributional models of Klar and colleagues (Klar & Giladi, 1997, 1999; Klar, Medding, & Sarel, 1996). The empirical results and model have many implications for the study of personal risk judgments, the optimistic bias, and risk-taking behavior.     

Contextual determinants of strategic choice: Some moderators of the availability bias

Three studies explored how the influence of the ‘availability heuristic’ on frequency judgement is mediated and moderated by the perceived meaning of the task, the perceived relevance of information for the task, and the salience of differential memorability of information. All studies adapted the ‘fumous names ’paradigm (Tversky and Kahneman, 1973) in which subjects are required to listen to a list of names of known personalities of both sexes and then judge the frequency of men and women. The availability heuristic (Tversky and Kahneman, 1973) posits that classes whose instances are easy to imagine or recall will be perceived as relatively frequent, so that when names of one sex are more famous and thus memorable this category will be rated as more numerous even when it occurs less frequently. Consistent with the notion that the use of availability is sensitive to task interpretation, we showed that the availability effect is eliminated over successive trials (Study 1) and moderated when task instructions render different categories salient (Study 2). In the third study it is shown that conditions which facilitate awareness of the biasing relationship between gender and fame (memorability), decrease the use of the availability heuristic by moderating frequency estimates of the more famous category. Results of these studies emphasize the context-bound and strategic aspects of judgement.     

Judgments relative to patterns: how temporal sequence patterns affect judgments and memory

Six experiments studied relative frequency judgment and recall of sequentially presented items drawn from 2 distinct categories (i.e., city and animal). The experiments show that judged frequencies of categories of sequentially encountered stimuli are affected by certain properties of the sequence configuration. We found (a) a first-run effect whereby people overestimated the frequency of a given category when that category was the first repeated category to occur in the sequence and (b) a dissociation between judgments and recall; respondents may judge 1 event more likely than the other and yet recall more instances of the latter. Specifically, the distribution of recalled items does not correspond to the frequency estimates for the event categories, indicating that participants do not make frequency judgments by sampling their memory for individual items as implied by other accounts such as the availability heuristic (Tversky & Kahneman, 1973) and the availability process model (Hastie & Park, 1986). We interpret these findings as reflecting the operation of a judgment heuristic sensitive to sequential patterns and offer an account for the relationship between memory and judged frequencies of sequentially encountered stimuli.     

Cognitive Heuristics and AIDS Risk Assessment Among Physicians1

Physicians (N= 331) reported perceived risk of HIV exposure, worry about on-the-job HIV exposure, and experience with patients who test seropositive for the HIV. In addition, the use of the availability heuristic was examined by responses to questions about talking and reading about AIDS, and the use of the simulation heuristic was examined by responses to questions about imagining oneself being exposed to HIV on the job. Simulation of the HIV-exposure experience related significantly to perceived risk (p < .001), even after variance attributable to actual experience and use of the availability heuristic was taken into account. Availability of AIDS information related marginally to perceived risk after variance attributable to actual experience and use of the simulation heuristic was taken into account. Simulation related strongly with worry about on-the-job exposure (p < .001), and availability was not significantly related to worry after variance associated with simulation and experience with AIDS was removed. Implications of these results for physician training are discussed.     

Memory accessibility and probability judgments: an experimental evaluation of the availability heuristic.

Consistent with Tversky and Kahneman's (1973, 1974) availability heuristic hypothesis, the current study found a negative correlation between recall latency for past events and the perceived future probability of similar events. Furthermore, when the relative accessibility of memories of positive and negative events was experimentally manipulated using the Velten mood-induction procedure, the perceived future probabilities of similar events also changed in a manner consistent with the availability heuristic account. Reductions in recall latencies resulting from the mood manipulations were, as predicted, related to increases in perceived probability, and vice versa. Partial correlations indicated that this association between the observed patterns of changes in recall latencies and probability judgments could not be accounted for by the existence of independent associations between each of these effects and the magnitude of mood change.     

Counterfactual processing and the correspondence between events and outcomes: Normality versus value

Kahneman and Tversky (1982) have proposed a simulation heuristic such that perceivers tend to substitute ‘normal’ antecedent events for exceptional ones in psychologically ‘undoing’ a given outcome. Recently Gavanski and Wells (1989) have demonstrated that exceptional outcomes tend to be perceived as caused by exceptional events and normal outcomes by normal events, a finding more in line with the representativeness heuristic than this ‘normalization’ principle. We argue that representativeness may be determined by the evaluative tone of events as well as by probability—namely that positive events are assumed to underlie positive outcomes and negative events, negative outcomes. Both normality and value were independently manipulated in order to test the relative effects of each of these factors. In contrast to Gavanski and Wells our data indicate that preference was given to the similarity of value between events and outcome for undoing both positive and negative and normal and exceptional outcomes. Some implications of these findings for counterfactual processing are discussed.     

判断与决策中的情感启发式

情感启发式是指在判断与决策的过程中,个体会有意识或无意识的利用自己对任务选项的主观情感反应来做出决策。具体来说,个体头脑中物体和事件的表征会激起不同水平的情感体验,这种不同的体验会对所有的表征做出积极或消极的标记,人们根据这些被标记的体验来做出判断和决策。情感启发式是个体在决策中常用的策略。目前,关于情感启发式心理机制的解释主要有情感启发式模型和双加工理论。此外,情感启发式的影响因素主要包括经验、时间压力、可评估性和计数能力等。未来的研究应主要集中在探究情感启发式的产生根源和进一步扩展情感启发式应用领域的研究。     

The illusion of certainty: A catastrophe model of decision framing

Tversky and Kahneman (1981) have proposed that decision frames act to bias the processing of decision-relevant information by decision makers. Decision frames act as illusions to which most decision makers are susceptible. We believe that catastrophe theory provides a unique framework by which the effects of decision framing can be studied. Catastrophe theory has been proposed as a way to explain the sudden shifts in preference in perceptual experiments (Stewart & Peregoy, 1983). Tversky and Kahneman’s (1981) decision-framing concept, in decision situations, is proposed to be analogous to the cognitive, organizing centers underlying catastrophic changes in response in perceptual experiments. The results of this study were interpreted as demonstrating the heuristic value of catastrophe theory in describing the decision-framing phenomenon as a cognitive illusion. A version of this paper was presented to the Second Annual Convention of the american Psychological Society, June 7–10, 1990, Dallas, Texas.     

The role of risk perception and efficacy cognitions in the prediction of HIV-related preventive behavior and condom use

Abstract

Based on empirical findings on the central model variables of the Protection Motivation Theory, the influence of perceived susceptibility, perceived severity of the threat of AIDS, communicative and sexual self-efficacy, and outcome expectancy on various aspects of HIV-preventive behavior was examined. The study was based on a sample of 468 heterosexual adults between the ages of 20 and 45 years. The data were obtained by means of questionnaires filled out at various vacation sites that draw mass tourism or in the subjects' home town. The most significant predictor of behavior was found to be self-efficacy expectancy as regards assertiveness and use of HIV-related preventive measures. A high communicative self-efficacy expectancy, on the other hand, is associated with a higher level of risk behavior among certain subgroups and under certain behavioral aspects. This confirms the necessity of acknowledging the different forms of self-efficacy expectancy in sexual interactions. Perceived personal threat is also associated with risk behavior with respect to certain behavioral operationalizations. From this it can be concluded that one's own behavior is used as the basis for appraising one's susceptibility. The results also show that distinctions must be made when analyzing HIV-related risk behavior. In particular, a difference must be made between absolute behavior (degree of the risk behavior) and relative behavior (change - especially reduction - in risk behavior due to the danger of AIDS).     

The perception of bicycle crashes with and without motor vehicles: Which crash types do older and middle-aged cyclists fear most?

Several studies have focused on the perceived risk of bicycle crashes (irrespective of crash types) and concluded that cycling near high volumes of motor vehicles deters people from cycling. The perceived risk of bicycle crash types (with or without motor vehicles) has not yet been studied. Cyclists, both in countries with low and high levels of cycling participation, are substantially more likely to sustain severe injuries in single-bicycle crashes than in bicycle-motor vehicle crashes. This questionnaire study sets out to compare which bicycle crash types are perceived to cause most hospitalizations among cyclists. The study comprised cyclists over 55 years in the Netherlands, and over 40 years in the Belgian regions of Flanders (a region with high cycling participation), Brussels and Wallonia (regions with low cycling participation). The majority of cyclists (60%) perceive bicycle-motor vehicle crashes cause most hospitalizations among cyclists. This percentage is greatest in the areas of Brussels and Wallonia and lowest in the Netherlands. Cyclists who were involved in a bicycle-motor vehicle crash themselves are more likely to regard this crash type as the most common cause of hospitalizations among cyclists, while cyclists over 60 years who were involved in a crash without a motor vehicle are more likely to perceive that crash type as the most common cause. The smaller perception bias in the study areas with higher cycling participation – particularly the Netherlands and to a somewhat lesser degree Flanders – is probably due to bicycle infrastructure being more separated from high-speed motor traffic, leaving cyclists less exposed. The outcomes show that cyclists underestimate the likelihood of severe injuries due to single-bicycle crashes. New interventions should raise the awareness of the risk of single-bicycle crashes and provide solutions to avoid such crashes.     

A domain‐specific risk‐attitude scale: measuring risk perceptions and risk behaviors

We present a psychometric scale that assesses risk taking in five content domains: financial decisions (separately for investing versus gambling), health/safety, recreational, ethical, and social decisions. Respondents rate the likelihood that they would engage in domain‐specific risky activities (Part I). An optional Part II assesses respondents' perceptions of the magnitude of the risks and expected benefits of the activities judged in Part I. The scale's construct validity and consistency is evaluated for a sample of American undergraduate students. As expected, respondents' degree of risk taking was highly domain‐specific, i.e. not consistently risk‐averse or consistently risk‐seeking across all content domains. Women appeared to be more risk‐averse in all domains except social risk. A regression of risk taking (likelihood of engaging in the risky activity) on expected benefits and perceived risks suggests that gender and content domain differences in apparent risk taking are associated with differences in the perception of the activities' benefits and risk, rather than with differences in attitude towards perceived risk. Copyright © 2002 John Wiley & Sons, Ltd.     

Predictors of perceived susceptibility of breast cancer and changes over time: a mixed modeling approach

OBJECTIVE: To examine predictors of perceived susceptibility to breast cancer and assess differences across three dependent measures. DESIGN: Annual surveys were completed by US women veterans (N = 3,758) participating in a repeat mammography intervention trial. Multivariable non-linear mixed model analyses examined individual- and group-level changes in perceived susceptibility to breast cancer. DEPENDENT MEASURES: Three single-item measures of perceived susceptibility to breast cancer (percent risk, ordinal risk, and comparative risk likelihood). Predictors included demographic, health status, health behavior, affect, knowledge, and subjective norm variables. RESULTS: Breast symptoms and greater cancer worry increased perceived susceptibility for all three measures. Other predictors varied by dependent measure. Random change, indicating individual variability, was observed for percent risk only. CONCLUSION: Despite small model effect sizes, breast symptoms and cancer worry were consistent predictors and may be good targets for messages designed to influence women's perceived susceptibility to breast cancer. Researchers may benefit from using measures of perceived susceptibility with larger response scales, but additional measurement research is needed. Combining indicators of perceived susceptibility may be undesirable when different predictors are associated with different measures.     

先前情绪和过度自信对灾难事件后继风险决策的影响

研究考察了先前情绪和过度自信对灾难事件后继风险决策的影响。结果发现：(1)先前情绪的主效应显著, 积极情绪比消极情绪的个体在灾后风险决策时更加倾向于风险寻求;过度自信的主效应显著, 高过度自信比低过度自信个体在灾后风险决策时更加倾向于风险寻求。(2)先前情绪和过度自信水平交互影响灾难事件后继风险决策。高过度自信者在积极情绪状态下比在消极情绪状态下更倾向于风险寻求; 消极情绪状态下过度自信水平不同的个体之间没有显著差异。     

The cognitive representation of filmic event summaries

The present study compared two types of film summaries and a complete film event portrayal of two different event sequences, measuring their perceived structure during presentation and the subsequent ability to recall them. The summaries were based on the model of behavioural perception (Newtson & Engquist, 1976; Zacks & Tversky, 2001) and either retained the borders (breakpoints) or the middle parts (non‐breakpoints) of each segment of the event sequence. It was found that breakpoint‐keeping summaries were perceived to be more structured and were recalled more coherently and comprehensively than non‐breakpoint‐keeping summaries. On the other hand, breakpoint‐keeping summaries were not recalled any more completely than event portrayals that had not been shortened. Also, breakpoint‐keeping summaries showed only moderate overlap in their recalled event steps. Copyright © 2003 John Wiley & Sons, Ltd.     

Coping with stress through decisional control: Quantification of negotiating the environment

Coping with stress through ‘decisional control’ – positioning oneself in a multifaceted stressing situation so as to minimize the likelihood of an untoward event – is modelled within a tree‐structure scenario, whose architecture hierarchically nests elements of varying threat. Analytic and simulation platforms quantify the game‐like interplay of cognitive demands and threat reduction. When elements of uncertainty enter the theoretical structure, specifically at more subordinate levels of the hierarchy, the mathematical expectation of threat is particularly exacerbated. As quantified in this model, the exercise of decisional control is demonstrably related to reduction in expected threat (the minimum correlation across comprehensive parameter settings being .55). Disclosure of otherwise intractable stress‐coping subtleties, endowed by the quantitative translation of verbal premises, is underscored. Formalization of decisional stress control is seen to usher in linkages to augmenting formal developments from fields of cognitive science, preference and choice modelling, and nonlinear dynamical systems theory. Model‐prescribed empirical consequences are stipulated.     

Causal conjunction fallacies: The roles of causal strength and mental resources

In two experiments we tested the prediction derived from Tversky and Kahneman's (1983) work on the causal conjunction fallacy that the strength of the causal connection between constituent events directly affects the magnitude of the causal conjunction fallacy. We also explored whether any effects of perceived causal strength were due to graded output from heuristic Type 1 reasoning processes or the result of analytic Type 2 reasoning processes. As predicted, Experiment 1 demonstrated that fallacy rates were higher for strongly than for weakly related conjunctions. Weakly related conjunctions in turn attracted higher rates of fallacious responding than did unrelated conjunctions. Experiment 2 showed that a concurrent memory load increased rates of fallacious responding for strongly related but not for weakly related conjunctions. We interpret these results as showing that manipulations of the strength of the perceived causal relationship between the conjuncts result in graded output from heuristic reasoning process and that additional mental resources are required to suppress strong heuristic output.     

Modelling perceived risk and trust in driving automation reacting to merging and braking vehicles

Perceived risk and trust are crucial for user acceptance of driving automation. In this study, we identify important predictors of perceived risk and trust in a driving simulator experiment and develop models through stepwise regression to predict event-based changes in perceived risk and trust. 25 participants were tasked to monitor SAE Level 2 driving automation (ACC + LC) while experiencing merging and hard braking events with varying criticality on a motorway. Perceived risk and trust were rated verbally after each event, and continuous perceived risk, pupil diameter and ECG signals were explored as possible indictors for perceived risk and trust.The regression models show that relative motion with neighbouring road users accounts for most perceived risk and trust variations, and no difference was found between hard braking with merging and hard braking without merging. Drivers trust the automation more in the second exposure to events. Our models show modest effects of personal characteristics: experienced drivers are less sensitive to risk and trust the automation more, while female participants perceive more risk than males. Perceived risk and trust highly correlate and have similar determinants. Continuous perceived risk accurately reflects participants’ verbal post-event rating of perceived risk; the use of brakes is an effective indicator of high perceived risk and low trust, and pupil diameter correlates to perceived risk in the most critical events. The events increased heart rate, but we found no correlation with event criticality. The prediction models and the findings on physiological measures shed light on the event-based dynamics of perceived risk and trust and can guide human-centred automation design to reduce perceived risk and enhance trust.     

The effect of increasing the memorability of category instances on estimates of category size

According to Tversky and Kahneman’s (1973) availability heuristic, people sometimes make use of the ease with which instances are retrieved when they have to estimate proportions or frequencies. One implication of this availability heuristic is that any factor that affects memorability of instances from a category should also affect the estimated category size. In one of their experiments, Tversky and Kahneman found that, after being presented with a list of names, people judged the more famous names to be more frequent. Similarly, recall was found to be greater for the more famous names. Three experiments that used Tversky and Kahneman’s paradigm are reported. Repeating nonfamous names resulted in their increased recallability and a corresponding increase in estimates of their frequency (Experiments 1 and 3). Making nonfamous names more salient (Experiment 3) also had parallel effects on recallability and frequency estimates, indicating that different memory manipulations affected availability in a similar fashion. Furthermore, reliance on the heuristic was not changed as a function of prior knowledge (Experiment 2) or practice (Experiment 3)