Abstract
At any moment, the visual system is confronted with a huge number of stimuli, which exceeds our cognitive processing capacities. Different attentional control (AC) mechanisms guide attention and are responsible for selecting one of the many available stimuli; however, it is unclear whether they synergistically or independently operate in assigning attentional priority to a specific item/spatial location. Here we report four experiments, based on the same visual search task, in order to characterize the unique and combined influence of two AC mechanisms, namely goal-directed and experience-dependent signals. Specifically, Experiment 1 and 2 assessed the unique influence of goal-directed and experience-dependent control, respectively by presenting a (neutral/valid) central visual cue before the stimuli array onset, or by manipulating target probability (high/intermediate/low) across locations. Results showed better performance in valid- (vs. neutral-) cue trials and for targets in the high- (vs. low-) frequency location. By combining the described endogenous cueing and statistical learning (SL) protocols, Experiments 3 and 4 directly tested the combined effect of these two mechanisms on behavior and ERP markers. Behaviorally, we found a clear-cut interaction, namely goal-directed attention exerted a gating effect over experience-dependent priority assignment, with the latter emerging only in the absence of goal-directed guidance (neutral-cue trials). EEG data also revealed this interaction, however, regardless of the presence of goal-directed control, the N2pc elicited by targets in high-frequency location was larger than the N2pc elicited in the low-frequency location, suggesting a general attentional bias toward the location where the target is more likely to occur. Together, these findings confirmed both goal-directed and experience-dependent influences on attentional deployment and, when active together, a partially prevalence of goal-directed control over statistical learning.