Abstract
Visual search is more efficient when a subset of distractors is presented before the display containing the remaining distractors and a target. This benefit is known as the ‘preview effect’. It has been shown that whereas the preview effect disappeared in a brief preview (e.g., 150 ms) condition, it could be restored simply by showing the same items of the previewed distractors about half a second earlier before that brief preview condition, which suggested preview effect may be due to the inhibition of previewed distractors maintained in visual working memory. However, in the present study, we discovered the presence of preview benefit was strongly correlated to the availability of the visible persistence (rather than working memory) of those previewed distractors. In a ‘one-time top-up’ condition, the earlier exposure of the previewed distractors was presented once (2100 ms before the brief preview and lasted 450 ms). In a ‘repeated top-up’ condition, the earlier exposure of the previewed distractors was repeated three times (2100 ms before the brief preview; lasted 450 ms and followed by a 250 ms blank period in each repeat). A clear preview effect was present in the ‘repeated top-up’ condition, but no preview effect was present in the ‘one-time top-up’ condition. In fact, in the ‘repeated top-up’ condition, the visible persistence of the previewed distractors was strongly shortened as demonstrated in a missing-dot paradigm, whereas the 2100 ms earlier exposure was sufficient for establishing a working memory representation of the previewed distractors. Therefore, the present findings suggested that the visible persistence rather than working memory might be the main underlying mechanism of the preview effect.