The time-course of pop-out search

Abstract

Olds, Cowan and Jolicoeur [2000. Tracking visual search over space and time. Psychonomic Bulletin & Review (in press)] interrupted pop-out search by adding distractors to a display after a delay. They analyzed the response time distributions from conditions with different delays for interruption and showed that when pop-out search fails, its partially completed computations can be used to assist other, slower search processes. This paper demonstrates that expectancies, numbers of items and colors in the display, and color onsets do not explain those results. Finally, an experiment in which the target was moved mid-trial demonstrates that partial pop-out assists difficult search by indicating something about where the target is, or where the target is not.

Pop-out from abrupt visual onsets

“…Olds, Cowan and Jolicoeur, 2000;Nothdurft, 2000). If these masking items appear too quickly, then pop-out is prevented.…”

Inefficient conjunction search made efficient by concurrent spoken delivery of target identity

“…On a much broader time scale than that used in Olds et al's (2000aOlds et al's ( , 2000b experiments, Humphreys (1997, 2002) presented one set of colored distractors for a full second before adding to the display a set of different-colored distractors plus the target. They found that participants seemed to remember which distractors had already been discarded as nontargets during that initial second and thus were able to locate the target very efficiently.…”

“…This process can be facilitated by at least two kinds of help-search assistance and visual marking-that seem to work by narrowing down the set of locations at which the target might be found. For example, in the experiments conducted by Olds et al (2000aOlds et al ( , 2000b and Humphreys (1997, 2002), the visual display was incrementally delivered, providing information about locations that no longer needed to be considered and narrowing the search through a restriction in the number of relevant locations.…”

Partial orientation pop-out helps difficult search for orientation

“…The results of these experiments provide basic constraints that must be satisfied by any model of early vision and visual selection. Because all visual processing is affected by which portions ofthe visual field these early mechanisms select for further analysis, it is important to determine the nature ofeach selection mechanism, as well as interactions between the mechanisms.All of the results of Olds et al (2000aOlds et al ( , 2000b were based on experiments in the color domain. Are the results specific to color, or can they be generalized to other stimulus dimensions?…”

“…All of the results of Olds et al (2000aOlds et al ( , 2000b were based on experiments in the color domain. Are the results specific to color, or can they be generalized to other stimulus dimensions?…”