Linking stages of conflict-processing across behavioral and electrophysiological data

In the arrow flanker task (Eriksen & Eriksen, 1974), participants have to respond to a central target stimulus while ignoring irrelevant flankers. Mathematical models of conflict processing in the task assume that the response selection process is affected by the processing of interfering flankers until those have been inhibited. For example, the dual-stage two-phase (DSTP) model assumes that attention is in a first stage evenly distributed across the target and flanking stimuli and in the second stage focused solely on the target once irrelevant flankers have been inhibited. In contrast, the shrinking spotlight (SSP) model assumes that attention gradually shifts toward the target stimulus (White et al., 2011). Although both models capture main trends in behavioral data, little is known about how they relate to electrophysiological correlates of conflict resolution and response selection such as the stimulus-locked lateralized readiness potential (sLRP). Using data from 150 participants who completed an arrow flanker task while their EEG was recorded, we integrated parameters of the two mathematical models and electrophysiological correlates of conflict resolution (sLRP peak latencies) in a multi-layer structural equation model framework. Parameters of the mathematical models and electrophysiological correlates of conflict resolution were meaningfully related to each other and demonstrated convergent validity. Both models produced comparable results, but the DSTP model was found to be superior to the SSP model in mapping to ERP measures that reflect sequential processing stages. The findings suggest that both models can help understand how individuals resolve conflicting stimuli, and the DSTP model may be more easily related to electrophysiological measures that capture sequential processing stages.