Violations of economic rationality due to irrelevant information during learning in decision from experience

According to normative decision-making theories, the composition of a choice set should not affect people’s preferences regarding the different options. This assumption contrasts with decades of research that have identified multiple situations in which this principle is violated, leading to context effects. Recently, research on context effects has been extended to the domain of experience-based choices, where it has been shown that forgone outcomes from irrelevant alternatives affect preferences — an accentuation effect. More specifically, it has been shown that an option presented in a situation in which its outcomes are salient across several trials is evaluated more positively than in a context in which its outcomes are less salient. In the present study, we investigated whether irrelevant information affects preferences as much as relevant information. In two experiments, individuals completed a learning task with partial feedback. We found that past outcomes from non-chosen options, which contain no relevant information at all, led to the same accentuation effect as did counterfactual outcomes that provided new and relevant information. However, if the information is entirely irrelevant (from options that could not have been chosen), individuals ignored it, thus ruling out a purely perceptual account of the accentuation effect. These results provide further support for the influence of salience on learning and highlight the necessity of mechanistic accounts in decision-making research.