When global and local information about attentional demands collide: evidence for global dominance.

This study investigated how global and local information about attentional demands influence attentional control, with a special interest in whether one information source dominates when they conflict. In Experiment 1, we manipulated proportion congruence in two blocks (i.e., mostly congruent versus mostly incongruent) of a Stroop task to create different global demands (i.e., low versus high, respectively). Additionally, we created different local demands by embedding 10-trial lists in each block that varied in their proportion congruence (10% to 90% congruent), and half the lists were preceded by a valid precue explicitly informing participants of upcoming attentional demands. Stroop effects were smaller in mostly incongruent compared with mostly congruent blocks demonstrating the influence of global information. Stroop effects also varied according to the proportion congruence of the abbreviated lists and differed between cued and uncued lists (i.e., cueing effect), demonstrating the influence of local information. Critically, we found that global and local information interacted, such that the cueing effect differed between the two blocks. While there was evidence that participants used the precue to relax control for mostly congruent lists within the mostly congruent block, the cueing effect was absent within the mostly incongruent block. In Experiment 2, we replicated the latter pattern and thereby provided further evidence that participants do not use local precues to relax control when attentional demands are globally high. The findings suggest that both global and local information sources influence the control of attention, and global information dominates local expectations when the information sources collide.