Congruency Effects in the Attention Network Task: The Influence of Stimulus Onset Asynchrony and Eye Movements

Abstract

Prior research using the Attention Network Test (ANT) has shown larger reaction time differences between incongruent and congruent targets (i.e., congruency effect) on alert with respect to non-alert trials. The ANT typically requires participants to maintain central eye fixation while targets are presented at a discrete cue-to-target interval. However, it is unclear if congruency effects are modulated by eye movements and if the magnitude of the congruency effect changes over time. To address these issues, we had participants perform a gaze-contingent variant of the ANT, with targets presented at central fixation (eye fixed trials) or at a peripheral location after an eye movement (saccade trials). Each trial began with an alert cue indicating whether to maintain central fixation or immediately make a saccade to one of four peripheral locations (small circle at NE, NW, SW, SE quadrants). On saccade trials, participants were instructed to hold fixation at the peripheral location until the target array appeared. Target arrow arrays (congruent and incongruent) were presented at one of three intervals (50, 350, 750ms) with respect to the offset of the alert cue, in eye fixed trials, or fixation onset in the saccade trials. The results revealed that congruent targets produced faster reaction times and higher accuracy with respect to incongruent trials. The magnitude of the congruency effect was largest at the 700ms interval for eye fixed trials whereas saccade trials produced the largest congruency effect at the 50ms interval. These results suggest the magnitude of conflict on incongruent trials changes over time and the nature of this change is modulated by saccade related processes.

Acknowledgement: ARL-74A-HR53