형법상 ‘과실’ 판단시 사후과잉확신편향의 영향력에 관한 실증적 연구

The Effect of Hindsight Bias in Negligence Judgements in Criminal Cases

Once individuals learn the outcomes of events, they tend to overestimate the ability with which they could have predicted the event(hindsight bias). Meta-analyses have shown that the hindsight bias is a robust effect, is applicable in a myriad of circumstances, and is difficult to debias. Regarding negligence judgments, legal decision makers must decide if defendants’ actions were negligent by determining whether a defendant should have foreseen the potential for harm. However, legal decision makers make these judgments with outcome knowledge that harm did occur, introducing the hindsight bias. The reason why hindsight bias is specially dangerous in negligence judgments is that it means guilty-biased judgments, which is contrary to the constitution, the presumption of innocence. This study investigates whether hindsight bias affect’s legal decision making in negligence judgments in criminal cases in the context of Korea. 149 college students(lay persons) and 185 law school students(legal experts) participated in the experiment, and three scenarios adapted from real criminal cases were used as experiment materials. The front part of the scenarios are all the same, but the contents of outcomes are different ; one scenario contains the injury outcome caused by the actor’s behave, another one shows non-injury outcome, and the other one does not suggest any outcome. Subjects rated the actor on negligence. Results indicated that the judgements of law school students were not biased by the outcome information, while college students were affected by the outcome information, showing hindsight bias. Moreover, it can be confirmed through qualitative analysis on the open question about the reason of the judgement that college students are more likely to depend on the ‘outcome information’ when they make a decision, showing that lay persons are more vulnerable to hindsight bias than legal experts. This study suggests the necessity of continuous research on the risk of cognitive bias in the investigation and trial by showing the result that the hindsight bias influences the legal decision making.