What is normal? Dimensions of action-inaction normality and their impact on regret in the action-effect

The widely-replicated action-effect describes a phenomenon in which negative outcomes are associated with higher regret when they are a result of action compared to inaction. The highly influential norm-theory theorised that the effect could be explained using the concept of normality, arguing that inaction is more “normal”. I aimed to clarify the concept of normality and examine the impact on regret in the action-effect by contrasting three identified categories: past-behaviour normality, expectations normality, and social-norms normality. In three exploratory experiments (N1 = 213, N2 = 300, N3 = 303) and one concluding pre-registered combined experiment (N = 403) I found that the three normality categories had distinct effects with consistent medium to strong impact on regret in the action-effect (d = .51 to d = .85) and no interactions. Action-effect was significantly weakened into an inaction-effect in the joint effects of any two types of the three normality categories (d = 1.56–1.61) and with all three combined (d = 2.75). In total, I concluded three replications for effects of each of the normality dimensions, overall nine successful replications of previous findings. All materials, data, and code are available on https://osf.io/wmkpe/.