Selection history influences an attentional decision bias toward singleton targets.

Selection history effects are ubiquitous findings that show how implicitly encoding a target's feature or location on a trial can facilitate target activation on the following trial. Although the target-defining feature (e.g., color) is usually unpredictable, it is often relevant to determining the target on a given trial. The present study used a feature priming task, like the three-item oddball search task, but varied the target-defining feature (shape) orthogonal to the priming feature (color) that could influence target activation. On any trial the target could be a color singleton or not, and the target's feature could repeat or switch between trials. Larger priming effects were seen when the current target was a color singleton than a nonsingleton. Importantly, diffusion analyses showed that pretrial selection bias contributed to these larger priming effects. The results suggest selection history facilitates target activation through an attentional decision bias to select the object with the most recently attended color, and this attentional decision is easier when the current target is also distinct.