Abstract
In pop-out search, repetition of an attention-driving feature facilitates search on the current trial. This priming of pop-out is known to be due to a decaying memory trace of the attention-focus features; however there is no explicit consensus of the locus of the memory trace that influences the current trial. We investigated two possible mechanisms of priming of pop-out: a trace of the previous feature stored in visual short-term memory (VSTM) and a trace along perceptual level features. Experiment 1 replicated the priming of pop-out effect with a task of discriminating the gap location of odd-colored Landolt C shaped objects. In Experiment 2, a VSTM load was added to the pop-out search; occupying VSTM did not interfere with the priming of pop-out effect. In Experiment 3, we intervened an irrelevant task (discriminating the orientation of a pointing object) between pop-out search trials. Results showed that even though the intervening task was not related to the current pop-out search task, the color of the object for intervening task influenced on the current pop-out search task. These results suggest that the priming of pop-out might not be due to a memory trace in VSTM, but rather might be due to the perceptual level feature weight changes for attended objects.