Abstract: Whether serially presented stimuli can be processed simultaneously or sequentially are tested by adopting a simplified AB paradigm. It was found that, when two stimuli (Target and Probe, T & P for short respectively) were serially presented without distracter between them, their pattern of RT matched the prediction of the Parallel Model exactly (Experiment 1). However, when T was immediately followed by a backward mask (in other words, T & P were interrupted by a distracter), T & P’s pattern of RT accorded with the Serial Model (Experiment 2). These patterns of results indicated that serially presented stimuli which have no distracter between them can be processed simultaneously. And this kind of parallel mechanism is extremely capacity-limited and possibly deals with only two objects simultaneously. Moreover, it can be interrupted by long interval between two targets.

Key words: Parallel model, Serial Model, Attention Blink