Intertrial inhibition of focused attention in pop-out search

When a visual search for a color oddball is performed, responses to target-present trials are affected by the color of items in immediately preceding target-absent trials, a phenomenon known as the distractor-previewing effect (DPE). Specifically, the color of the items in the target-absent trial suppresses responses to a target of that color in the subsequent trial, even though participants report a target feature uncorrelated with color. We believe that this suppression reflects a transient inhibitory effect on focused attention that biases attention away from items that are of the same color as the items in the target-absent trial. Experiments 1-3 show that the DPE is present only in tasks that require focused attention. Experiments 4A and 4B show that the DPE persists even when target-absent displays are masked. Last, Experiment 5 shows that the DPE emerges as early as within the first 100 msec of a target-present trial and is fully in place by the 250-msec mark.