DMCfun: An R package for fitting Diffusion Model of Conflict (DMC) to reaction time and error rate data

Decision processes within choice reaction-time (CRT) tasks are often modelled using evidence accumulation models (EAMs), a variation of which is the Diffusion Decision Model (DDM, for a review, see Ratcliff et al., 2016). Ulrich et al. (2015) introduced a Diffusion Model for Conflict tasks (DMC). The DMC model combines common features from within standard diffusion models with the addition of superimposed controlled and automatic activation. The DMC model can explain data behavioural patterns within common conflict-like tasks, where stimulus features include both a relevant and irrelevant source of information (e.g., Simon task). This paper introduces the R-package DMCfun, which implements the DMC model and provides functionality to fit the model to observed data. Furthermore, the package can be used to perform and illustrate distributional analyses on data from any conflict-like CRT task.