Evidence accumulation models of Navon interference

The Navon task is a classic paradigm to study selective attention, in which participants identify target letters presented at either a local or global level within compound figures. Traditionally, differences in reaction time (RT) between local and global trials – precedence effects – are used to quantify individual biases towards local or global processing. However, such RT-based measures conflate attentional bias with general differences in speed-accuracy trade-offs. Here, we applied evidence accumulation models to dissociate these mechanisms and evaluate whether Navon interference reflects conflict resolution processes similar to those in tasks such as the Flanker and Simon paradigms. Participants performed a letter-Navon task with congruent and incongruent trials with local or global focus. We fitted four models – the Diffusion Decision Model, Dual-Stage Two-Phase model, Shrinking-Spotlight model, and Diffusion Model of Conflict. All models captured the overall RT distributions and conditional accuracy functions, but evaluation of model complexity and parameter estimates favoured the Dual-Stage Two-Phase and Diffusion Decision models as the principal accounts of Navon interference. The findings support an interpretation of the Navon task as a conflict-resolution paradigm and demonstrate that evidence accumulation modelling provides a principled framework for disentangling attentional and strategic contributions to selective attention performance.