Anthony W. Sali¹ (), Emily O. Oor¹, Terrence R. Stanford², Emilio Salinas²; ¹Wake Forest University, ²Wake Forest University School of Medicine

During natural behavior, the relevant timescale over which attention varies is on the order of a few tens of milliseconds, and although non-invasive measures of brain activity such as electroencephalography (EEG) and event related potentials (ERPs) have the requisite temporal resolution, traditional psychophysical measures of attention do not. Across two experiments, we combined ERP measures of attentional selection with a novel oculomotor decision paradigm capable of resolving the contributions of both voluntary and involuntary attention to behavioral performance with unprecedented temporal resolution. Participants completed a compelled saccade task in which they made an eye movement toward or away from a salient color change based on the color. By cuing participants to initiate their movement before the color cue, varying the temporal gap between this go signal and the color cue, referred to as the processing time (PT), and placing a strict limit on response times, we measured the rise and fall of stimulus-driven attentional priority. In both experiments, participants’ behavior was characterized by guesses at the shortest PTs, reflexive orienting toward the salient color onset at intermediate PTs, and goal-directed override of stimulus salience at the longest PTs. Furthermore, the amplitude of the P1 ERP component was significantly larger for trials with reflexive responding PTs relative to those associated with goal-directed control. In Experiment 2, aging was associated with a slower rise in reflexive responding as PT increased as well as a delay in goal-directed override of salience-based priority. Together, our results suggest that the ability to override reflexive oculomotor orienting takes longer in older adults and is more broadly associated with increased early sensory processing.

Acknowledgements: Wake Forest University Intercampus Pilot Grant