Ten Years Diffusion Model for Conflict (DMC) Tasks: Theoretical Foundations, Applications, Practical Recommendations, and Open Challenges

A central question in cognitive psychology concerns how humans selectively attend totask-relevant information whilst ignoring task-irrelevant information. This question isfrequently studied using conflict tasks, such as the Simon, Eriksen flanker, and Strooptasks, that require responses to relevant stimulus features while ignoring irrelevant, andpotentially conflicting, features. While all conflict tasks produce better performance ontrials where task-relevant features and irrelevant features match—a phenomenon known asthe congruency effect—they differ markedly in their RT distributions. The Diffusion Modelfor Conflict tasks (DMC) was introduced as a model to formally account for alldistributional patterns in conflict tasks. It integrates dual-route theories of cognitivecontrol into the framework of sequential sampling models by positing two superimposed,independent evidence accumulation processes: a linear one for controlled processing of thetask-relevant information, and a pulse-like one for automatic processing of thetask-irrelevant information, where activation first increases until a maximum and thendecreases again. This review summarizes DMC’s architecture, its core parameters, and itsability to account for various distributional patterns. We review and discuss applications ofDMC across several psychological domains, and technical considerations such as parameterestimation and recovery. Limitations of the model are critically assessed, and fields of openresearch are outlined. Overall, DMC offers a general account of conflict processing. Whilea powerful tool for quantifying the dynamics of selective attention and cognitive control,there is still a limited standardization in its application and more research is needed toextend DMC to other classes of conflict tasks.