Mechanisms of attentional selection: Temporally modulated priority tags

Abstract

When a single abrupt onset appears in a multielement display, it captures attention. When multiple onset elements occur, they have conditional priority over no-onset elements such that a limited number of onsets can be serviced with high priority in visual search (Yantis & Johnson, 1990). We report three experiments in which we assess two possible mechanisms for attentional prioritization: a priority queue into which a fixed number of high-priority elements are placed for early servicing during search, and a mechanism that temporarily tags all high-priority elements for early servicing or more frequent sampling. We manipulated the visual quality or interletter confusability ofthe stimuli to prolong encoding and/or comparison operations; this manipulation led to a decrease in the estimated number of elements serviced with high priority. We conclude that a mechanism incorporating temporally decaying priority tags is implicated in servicing multiple abrupt onsets in visual search.The complexity of visual perception requires an efficient selection mechanism that constrains the current visual task so that it is momentarily tractable (Tsotsos, 1988). Selective attention sets priorities that are used for a variety of visual tasks, including efficient visual search. For example, the guided search model of Cave and Wolfe (1990) suggests that an activation value is computed for each element in a visual display according to its similarity to the target on several dimensions and its conspicuity in the display (i.e., its dissimilarity to nontarget elements). Elements are then processed serially in order of their activation strengths. Similar models have been advanced by others (e.g., Bundesen, 1990;Duncan & Humphreys, 1989;Koch & Ullman, 1985).These models all include some kind of prioritizing system in which preliminary decisions are made about which stimuli will be processed first (in serial models) or sampled more frequently (in parallel models). In most cases, a distinction is made between bottom-up or stimulusdriven selection, and top-down or goal-directed selection. In the present article, we describe three experiments in which we investigated one aspect of attentional prioritization via stimulus-driven attentional interrupts generated by abrupt visual onsets.This research was supported by National Institute of Mental Health Grant ROI-MH43924 to Steven Yantis. We are grateful to Vibha Thakral and Elizabeth Graham for excellent technical assistance, and to Howard Egeth, Doug Johnson, Jim Johnston, and Toby Mordkoff for valuable suggestions concerning the research. Our thanks to Lester Krueger, John Palmer, and two anonymous reviewers for their helpful comments on an earlier draft of the article. Correspondence should be sent to Steven Yantis, Department of Psychology, Johns Hopkins University, Baltimore, MD 21218 (e-mail: yantis@jhuvms). Abrupt Onsets and AttentionSeveral lines of research have provided empirical evidence for attentional capture by abrupt onsets.' For example, Todd and Van Gelder (1979) developed the no...

Spatiotemporal Segregation in Visual Search: Evidence From Parietal Lesions.

“…A noticeable difference from Yantis & Johnson's (1990) findings is that here, a maximum of between one and two items was prioritized, whereas Yantis and colleagues found prioritization of up to four items (Yantis & Johnson, 1990;Yantis & Jones, 1991; see also Pylyshyn, 1989). There may be several explanations for this difference.…”

“…It assumes that a number of abrupt new onsets are tagged for selection and that this tagging process is limited in capacity. The tagged items receive priority over older, offset-defined items and also over onsets that remain outside the capacity-limited tagging process or whose tags have decayed (Yantis & Jones, 1991). The model simply assumes that the tagged items are searched first, in a serial fashion, after which the remaining items are searched.…”

“…It is possible that Yantis and Johnson's (1990) participants prioritized more items than they could localize correctly. Other differences include having to perform two tasks and having to remember the cued locations over an extended period of time here, possibly leading to stronger interference and/or decay of activity associated with the cues (Yantis & Jones, 1991).…”

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“…Objects with a stronger luminance contrast, for example, may benefit from selective visual attention when presented together with objects of a lesser contrast (e.g., Yantis & Jones, 1991;Dresp & Grossberg, 1999). Similarly, some colors may attract attention away from other colors in the visual field, the color red in particular.…”

Attentional capture and aging: Implications for visual search performance and oculomotor control.

“…Illinois 61801. Electronic mail may be sent to akramer@s.psych.uiuc.edu.For example, Yantis and colleagues (Yantis & Hillstrom, 1994;Yantis & Jones, 1991;Yantis & Jonides, 1984 have conducted a number of studies in which subjects searched for a predefined target letter that could appear among other letters in a display. In each display, all but one of the letters were constructed by removing segments of figure eight premasks.…”