Out with the old: New target templates impair the guidance of visual search by preexisting task goals.

Representations of known target features (attentional templates) guide attention towards target objects during visual search. Recent research has shown that templates for different target-defining attributes can be maintained simultaneously, but interactions between multiple templates have not yet been studied systematically. Here, we investigated the competition between long-term (sustained) and short-term (transient) search goals in tasks where participants searched for targets defined by one of two possible colors. One target color remained constant across blocks or runs of trials, while the other changed on every trial. Both colors were indicated at the start of each trial by cue displays. To assess the efficiency of target selection processes guided by sustained and transient color templates, RTs and N2pc components were measured in Experiment 1 for search displays that contained a target in the constant or variable color. Results revealed robust sustained-template costs. RTs were slower and N2pc components emerged later and were smaller for sustained-color as compared to transient-color target objects. Experiments 2 and 3 demonstrated that this cost emerged rapidly, within two trials after a new constant color template had been established. These findings suggest that the activation of a new top-down search goal impairs the ability of a pre-existing template in working memory to guide attention towards target objects, reflecting a new type of retroactive interference in the control of visual search. These findings also have implications for our understanding of interactions between short-term task goals and longer-term attentional biases associated with the affective or motivational valence of objects.