Traditional priming-of-popout (PoP) experiments involve an observer whose goal is to specify an oddball stimulus (target) among irrelevant items (distractors). Research has shown that repeated PoP trials result in reduced response times (RTs). Recent studies added free choice trials intermixed with traditional PoP. Results of these studies show that preceded items are favoured over those previously ignored. Separation of the effects of the target and distractors emphasize these findings. Moreover, selection seems to affect subsequent PoP RTs. There, the separate roles of selected (target) and non-selected (distractor) items have not been investigated. This was the purpose of our study. Method: Nine students participated in the experiment. We intermixed six variations of 600 PoP trials where one target was presented among two distractors with three variations of 1600 free choice trials with two dissimilar targets. A neutral stimulus was introduced to separate the effects of the target and distractors. Results: Conditions where the selected stimulus became a neutral item on the following trial yielded the fastest RTs. Also, repetition of distractor items reduced RTs further. Conclusion: Neutral items have an attention grabbing effect which either facilitates or inhibits recognition. Furthermore, results highlight the importance of distractor repetition in priming.
Elva Bergþóra Brjánsdóttir