Eriksen's two-phase model of spatial selective attention: Physiological evidence of trial-mixing-dependent response inhibition.

The early work of Charles W. Eriksen and colleagues provided us with both the flanker task and the concepts of response competition and continuous flow. The model of the flanker task that Eriksen and colleagues developed also includes the idea that processing occurs in two phases and the specific claim that pro-active response inhibition is employed to prevent errors under certain conditions. We first replicated and extended the behavioral evidence that motivated this specific claim and then tested it using a variety of physiological measures. We verified the prediction of Eriksen's Two-Phase Model of Spatial Selective Attention using the lateralized readiness potential and contingent negative variation. We also clarified a detail of the model using electromyographic activity and response force. We note that this contribution of Charles W. Eriksen has not received the attention that it deserves and that several recent models might need to be revised in light of Eriksen's work.