Electrophysiological evidence for the optimal tuning of attention

Optimal tuning of attention refers to shifts in goal-driven attention that increase the difference between the representation of the target and nontarget features. Evidence for optimal tuning comes from studies measuring the memory representation of the target and, to a lesser degree, from studies measuring attentional selectivity. In one study on attentional selectivity, cueing effects were found to be greater for cue colors deviating away from the nontarget color compared to cue colors deviating toward the nontarget color, suggesting that participants' search goal was optimally tuned. To address alternative accounts, we measured event-related potentials (ERPs) elicited by different cue colors at posterior electrodes PO7/PO8. We found that ERPs associated with attentional orienting (N1pc) or selection (N2pc) were larger for cue colors deviating away from the nontarget color, which is consistent with the optimal tuning of attention. In contrast, the results are difficult to reconcile with alternative accounts such as rapid disengagement or object updating. Further, we aimed to evaluate contributions from sensory adaptation by analyzing the Ppc component, a lateralized ERP in the P1 time range. Two control conditions, however, suggested that the Ppc was more likely driven by imbalanced saliency than sensory adaptation.