Task-Constrained Interleaving of Perceptual and Motor Processes in a Time-Critical Dual Task as Revealed Through Eye Tracking

A multimodal dual task experiment that contributed to the original development and tuning of the EPIC cognitive architecture is revised and revisited with the collection of new high fidelity human performance data, most notably detailed eye movement data, that reveal the complex overlapping of perceptual and motor processes within and between the two competing tasks. The data permit a new detailed evaluation of assumptions made in previous models of the task, and contribute to the development of new models that explore opportunities for overlapping visual-perceptual, auditoryperceptual, ocular-motor, and manual-motor activities. Three models are presented: (a) A hierarchical task-switching model in which each task locks out the other; the model explains reaction time but does not account for eye movement data. (b) A maximum-perceptual-overlap model that maximizes parallel processing and predicts the trends in the eye movement data, but performs too quickly. (c) A moderately-overlapped model that introduces task-motivated constraints and predicts both reaction time and eye movement data. The best-fitting model demonstrates the complex taskconstrained interleaving of perceptual and motor processes in a time-pressured dual task.