Omission bias, individual differences, and normality

Omission bias is the preference for harm caused by omissions over equal or lesser harm caused by acts. Recent articles (Connolly & Reb, 2003; Patt & Zeckhauser, 2000; Tanner & Medin, in press) have raised questions about the generality of this phenomenon and have suggested that the opposite bias (action bias) sometimes exists. Prentice and Koehler (2003) have suggested that omission bias is sometimes confounded with a bias toward what is normal, a bias they find. We review this literature and report new data showing omission bias with appropriate methods, as well as a small normality bias that cannot explain the omission bias. The data suggest that the bias is largely based on the distinction between direct and indirect causation, rather than that between action and inaction as such. We report substantial individual differences: some subjects show action bias. We argue, though, that concern about omission bias is justified if only a substantial minority of people show it.     

The “identified victim” effect: an identified group,or just a single individual?

People's greater willingness to help identified victims, relative to non‐identified ones, was examined by varying the singularity of the victim (single vs. a group of eight individuals), and the availability of individually identifying information (the main difference being the inclusion of a picture in the “identified” versions). Results support the proposal that the “identified victim” effect is largely restricted to situations with a single victim: the identified single victim elicited considerably more contributions than the non‐identified single victim, while the identification of the individual group members had essentially no effect on willingness to contribute. Participants also report experiencing distress when the victim is single and identified more than in any other condition. Hence, the emotional reaction to the victims appears to be a major source of the effect. Copyright © 2005 John Wiley & Sons, Ltd.     

Arbitrary social comparison,malicious envy,and generosity

Existing work on the effects of social comparison on envy and generosity typically involves manipulation of social comparison with respect to dimensions that carry personal meaning and reflect upon the self, for example, performance, ability, or achievement. In the current work, we examine the effects of social comparison based on a purely arbitrary, manipulated situation. We measure malicious envy via monetary decisions that have real consequences for the target of comparison, in place of a self-reported questionnaire. In addition, we test the effects of the preliminary social comparison on generosity in a subsequent and ostensibly unrelated situation. In Experiment 1 we demonstrate the effect of randomly manipulated upward social comparison on a monetary allocation decision, and we establish the link between this allocation decision and malicious envy. In Experiment 2 we show that upward comparison affects not only malicious envy towards the target of the comparison but also decreases generosity towards a third party in a subsequent, ostensibly unrelated situation. Experiment 3 shows the effect of this type of social comparison, beyond a specific direction, on reducing generosity towards a third party.     

‘Protective donation’: When refusing a request for a donation increases the sense of vulnerability

May refusing a request for a donation be conceived as ‘tempting fate’? Do people feel more vulnerable when they do not comply with such a request? In this paper we examine the link between subjective perceptions of vulnerability and people's willingness to help address a threatening cause. Results of five studies, examining a real life situation, hypothetical scenarios and a controlled lab game with actual monetary costs and rewards, show first, that deliberately helping is positively correlated with the perceived likelihood of becoming a victim of the same misfortune. Second, we show that refusing to donate to a threatening misfortune increases sense of vulnerability. Both phenomena occur especially for people with strong belief in a just world, who believe in a causal relationship between people's behavior and their fortune (rewards and punishments).     

Differential weighting of common and distinctive components

We investigated possible explanations of the finding that the relative weight (W) of common components in similarity judgments is higher for verbal than for pictorial stimuli. A serial presentation of stimulus components had no effect on verbal stimuli; it increased the impact of both common and distinctive components of pictorial stimuli but did not affect their relative weight. On the other hand, W was increased by manipulations that reduced the cohesiveness of composite pictures, such as separating, scrambling, and mixing their components. Furthermore, W was decreased by manipulations that enhanced the cohesiveness of composite verbal stimuli by imposing structure on their components. Verbal and pictorial representations of the same stimuli yielded no systematic differences in W.     

Judgements of compensation for misfortune: The role of expectation

In three questionnaire studies, we asked subjects how much compensation should be provided, by a third party, to an accident victim. We tested the hypothesis, derived from norm theory, that compensation would be greater when the injury was less to be expected, e.g. when the injury was caused by failure - as opposed to success - of a safety routine. To rule out the possibility that such expectation effects depended on subjects' anticipations of the reactions of the parties involved in the accident. the parties were said to be ignorant of factors that could affect these reactions. Effects of expectation were still found, even when subjects themselves judged the accident to be equally serious in all conditions. Information about what would have happened in the absence of the cause (e.g. if the routine had succeeded instead of failed) affected compensation. as predicted by norm theory, but expectation effects were found even when this information about counterfactuals was held constant, so norm theory cannot account for all the results. We suggest that subjects are applying simple heuristics unreflectively Subjects may also have attempted to fulfil an implicit social contract through their awards. The results cannot be explained through the hypothesis that compensation was optimal: the accident was the same, and it had no deterrent effect, so optimal compensation should be the same in all cases.     

Routine and the perception of time

The authors investigated the influence of routine on people's estimation of time, testing the hypothesis that duration is remembered as being shorter when time is spent in a routine activity. In 4 experiments and 2 field studies, the authors compared time estimations in routine and nonroutine conditions. Routine was established by a sequence of markers (Study 1), variation of the task (Studies 2 and 3), or the number of repetitive blocks (Study 4). As hypothesized, the duration of the task was remembered as being shorter in routine conditions than in nonroutine ones. This trend was reversed in experienced (prospective) judgments when participants were informed beforehand of the duration-judgment task (Study 3). In Studies 5 and 6, the authors examined remembered duration judgments of vacationers and kibbutz members, which provided further support for the main hypothesis.     

The affective costs of overconfidence

Positive illusions, though often beneficial (Taylor & Brown, 1988 ), can diminish the pleasure of outcomes. This prediction follows from decision affect theory. We investigated this prediction by measuring the confidence that recreational basketball players felt while making shots and the pleasure they felt with subsequent outcomes. Results showed that most players were overconfident. Those who were more overconfident tended to experience less enjoyment with their outcomes. Using individual parameter estimates from decision affect theory, we estimated how each player would have felt if their self assessments had been accurate. For the vast majority, better calibration would have led to greater pleasure. In a second study, we randomly assigned players to a debiasing treatment condition or a control condition. Relative to the control players, debiased players were better calibrated and derived greater average pleasure from the task. Copyright © 2004 John Wiley & Sons, Ltd.