Absolute and Relative Biases in Estimations of Personal Risk (original) (raw)
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Absolute and Relative Biases in Estimations of Personal Risk1
Journal of Applied Social Psychology, 1996
Two studies examined the accuracy of personal risk estimates, as determined by comparing mean estimates made by college students with population statistics for college-educated individuals. Study 1 suggested that optimistic biases (the tendency for people to think they are less at risk than the average person) arise more because people overestimating the average person's risk than because they underestimate their own risk. In Study 2, subjects rated their risk after being presented with risk statistics that were 150%, loo%, or 50% of the true values. Subjects' estimates decreased with decreases in the comparison statistics, as if subjects attempted to preserve their "below-average" status, but they changed less than did the statistics and were actually pessimistic in comparison to the 50% values. Implications for interventions designed to influence risk perceptions are discussed. At least in relative terms, people are unrealistically optimistic about their chances of avoiding many negative life events. When asked to compare themselves to peers, they judge their own risk to be below average. When asked to make separate risk judgments, they give lower risk ratings for themselves than they give for others.3 This "relative bias" in risk estimates appears even when subjects rate only a single target-self or other-and the ratings given the two targets are compared (Harris & Middleton, 1994). Pessimistic biases, in 'This research was supported in part by Colby College Social Science Grants 01-2207 and 01-2230 to the second author. The authors are grateful to Victoria Cluck and Linette Kindred at Rutgers University and Colleen Burnham, Dorothy Evertsen, and the student assistant staff at Colby College for their assistance with data collection, and to two anonymous reviewers for their comments on an earlier version of this manuscript.
Resistance of Personal Risk Perceptions to Debiasing Interventions
Cambridge University Press eBooks, 2002
The tendency to believe that one's own risk is less than that of others may reduce interest in health-protective behaviors. This article describes 4 attempts to reduce such optimistic biases. In Study 1, New Jersey residents (N = 222) were provided with lists of risk factors for several health problems. This manipulation was strengthened in Study 2 by presenting risk factors in such a way that participants (164 undergraduates) might see their own standing as inferior to that of others. In Study 3, risk factors were presented one at a time, and participants (190 undergraduates) incorporated them into a mental image of a high-risk individual. Finally, 374 undergraduates in Study 4 generated lists of personal attributes that they believed increased their risk. Optimistic biases were found in each study, but none of the manipulations reduced these biases consistently. In contrast, conditions using opposite manipulations often exacerbated the biases.
Personality and Social Psychology Review, 2001
The optimistic bias is defined as judging one's own risk as less than the risk of others. Researchers have identified numerous personal and situational factors that moderate the extent to which people display the bias. It is unclear, however, whether these moderators affect the bias by influencing people's personal risk estimates or their risk estimates for a target. A review of moderators of the optimistic bias reveals evidence for both influences. Moderators associated with negative affect (negative mood, dysphoria, trait and state anxiety, event severity, and proximity of feedback) and control related moderators (perceived control and prior experience) appear primarily to affect personal risk estimates. Positive mood affects target risk estimates. Finally, moderators that surround the comparison process appear to have different effects. Specifically, the type of comparison target appears to affect target risk estimates, whereas attention to personal risk-related behaviors...
Journal of Behavioral Medicine, 1987
A mailed questionnaire was used to obtain comparative risk judgments for 32 different hazards from a random sample of 296 individuals living in central New Jersey. The results demonstrate that an optimistic bias about susceptibility to harm-a tendency to claim that one is less at risk than one's peers-is not limited to any particular age, sex, educational, or occupational group. It was found that an optimistic bias is often introduced when people extrapolate from their past experience to estimate their future vulnerability. Thus, the hazards most likely to elicit unrealistic optimism are those associated with the belief(often incorrect) that if the problem has not yet appeared, it is unlikely to occur in the future. Optimistic biases also increase with the perceived preventability of a hazard and decrease with perceived frequency and personal experience. Other data presented illustrate the inconsistent relationships between personal risk judgments and objective risk factors.
The effect of target group size on risk judgments and comparative optimism: The more, the riskier
Journal of Personality and Social Psychology, 2006
In 5 experiments, college students exhibited a group size effect on risk judgments. As the number of individuals in a target group increased, so did participants' judgments of the risk of the average member of the group for a variety of negative life events. This happened regardless of whether the stimuli consisted of photographs of real peers or stick-figure representations of peers. As a result, the degree to which participants exhibited comparative optimism (i.e., judged themselves to be at lower risk than their peers) also increased as the size of the comparison group increased. These results suggest that the typical comparative optimism effect reported so often in the literature might be, at least in part, a group size effect. Additional results include a group size effect on judgments of the likelihood that the average group member will experience positive and neutral events and a group size effect on perceptual judgments of the heights of stick figures. These latter results, in particular, support the existence of a simple, general cognitive mechanism that integrates stimulus numerosity into quantitative judgments about that stimulus.
Organizational Behavior and Human Decision Processes, 1996
Five studies showed that people assess vulnerability to future controllable negative life events differently depending on whether it concerns: (a) generalized targets (e.g., the average peer), or (b) concrete and familiar targets (self or nonself). In the former case, adistributionalframework is applied which focuses on available statistical information such as groups’ base-rates. In the latter case, people apply asingularjudgmental perspective and focus on available individuating information such as personal dispositions and preventive actions. This perspective would typically lead to an optimistic bias in favor of concrete and familiar rather than generalized targets. Participants in Study 1 evaluated both self's and a spontaneously selected (non-intimate) peer's risk prospects as lower than those of their average peer in controllable but not uncontrollable future events or controllable and uncontrollable everyday negative events. Study 2 replicated the main findings in direct comparative judgments. In Study 3, verbal accounts and a measure of interest in the base-rate supported the singular-distributional analysis. In Studies 4 and 5, an optimistic bias was found in favor of a randomly assigned member of their small group to whom participants were yoked. These findings suggest that in addition to the classic “illusion of unique invulnerability” (e.g., Perloff & Fetzer, 1986), whereby participants judge themselves to be less vulnerable than the average group-member, there is an “illusion ofnonuniqueinvulnerability,” whereby participants judge also their singular group-members to be less vulnerable than the average group-member. Finally we discuss conditions in which apessimisticrather than the standard optimistic bias might occur in comparative risk comparisons.
Journal of Experimental Social Psychology, 2004
Price, Pentecost, and Voth (2002) argue that common rather than rare negative future life events elicit greater indirect self-others comparative optimism. We argue that this finding may reflect a measurement effect: Rare events generate small differences (but large ratios), whereas common events produce larger differences (but smaller ratios). In Study 1, we show that the greater is event's perceived frequency, the greater is the numerical value assigned to express a given degree of risk discrepancy. In Study 2, we found weak negative rather than positive relations between perceived event frequency and the sense of risk discrepancy. Thus, it is crucial to understand how participants relate the two risk probabilities to each other to estimate their indirect comparative optimism.
Individuals' Estimates of the Risks of Death: Part I—A Reassessment of the Previous Evidence
1997
It is widely argued that individuals have biased perceptions of health and safety risks. A reconsideration of the best-known evidence suggests that this view is the erroneous result of a failure to consider the implications of scarce information. Our findings imply that the hypothesis that people make unbiased estimates of hazard rates fails to be rejected by the very data that were initially used to reject it. Thus, we are able to reconcile the alleged existence of widespread bias in risk perception with other findings that such bias is less apparent in the case of job-related hazards. The seeming bias in estimating population-average death rates and the lack of such bias in assessing job risks are two manifestations of the same behavior, which is the optimal acquisition of costly information.