Abstract
When a colour/orientation conjunction search display is immediately preceded by a display that shows the colour of each upcoming search item (in the location where each search item will appear), search is faster after this colour-preview than after an orientation-preview (Olds & Fockler, 2004). One explanation for this feature asymmetry is that colour has priority access to attentional selection relative to features such as orientation and size. In support of this hypothesis, we show that this asymmetry persists even after colour and orientation feature search performance is equated.
However, in further experiments we show that the explanation is not so simple: for colour/size conjunction search, colour-previews were less helpful than size-previews (even though colour-feature search was easier than size-feature search). Finally, for size/orientation conjunction search, orientation-previews produced much slower search than size-previews (even though orientation-feature search was easier than size-feature search).
We conclude: (1) The ease of feature search does not predict the amount of facilitation (or disruption) by the feature-preview. (2) Overall, size-previews produced the fastest RTs relative to no-preview baseline (for both colour-size and size-orientation conjunctions), followed by colour-previews (for colour-orientation conjunction but not for colour-size conjunction); orientation-previews often produced slower-than-baseline RTs.
While each feature-preview may potentially facilitate search, the transition from feature-preview display to search display may also disrupt search processes, because of luminance and/or colour changes. An explanation of this set of results must focus on both facilitation and disruption: neither suffices alone, since conjunction search performance after feature-preview can be significantly better or significantly worse than baseline.
Olds, E. S. & Fockler, K. A. (2004).
Perception, 33, 195–216.
NSERC