The ways instructions affect argument evaluation remain largely unknown. There may thus be uncovered ways to improve people's argumentation as well as matters better left unsaid. We examined how accurate and biased argument evaluation differ between instructions that emphasise facts, objectivity, or conscience. Data from adult Finns (N = 1600) showed that highlighting objective evaluation of arguments was connected to lower myside bias and to greater discernment between strong and weak arguments than when considerations of conscience or factual information were emphasised. The clearest differences in argument evaluations were between the instructions emphasising objectivity and conscience. We also analysed whether the cognitive correlates of argument evaluation varied depending on the instructions and found no differences. Instead, higher actively open-minded thinking, scientific reasoning skills, and cognitive reflection correlated systematically with better ability to separate strong from weak arguments. They were also never positively related to myside bias in argument evaluation.
The omission bias refers to the tendency to judge harmful omissions as less immoral than equally harmful commissions. Rooted in the philosophical doctrine of doing and allowing, omission bias has often been treated as a principle in moral decision-making. Although extensively replicated among Western samples, little research has directly examined whether omission bias and its underlying processes generalise across cultures. The present study employed a 2 (China vs. US) x 2 (Commission vs. Omission) between-subjects design with 266 American and 275 Chinese participants. Participants evaluated scenarios in which either a commission or an omission led to the same harmful outcome. The omission bias in morality perceptions generalised across cultures, although not for all scenarios. Intentionality and causality perceptions were significant predictors of immorality, robust across cultures and scenarios. Scenario-specific reversals of omission bias reflected shifts in intentionality and causality. These findings provide cross-cultural evidence for an attributional asymmetry account of omission bias.
