The psychophysics of visual search

Palmer, John; Verghese, Preeti; Pavel, Misha

doi:10.1016/s0042-6989(99)00244-8

Cited by 423 publications

(517 citation statements)

References 147 publications

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“…In particular, it is only a complete summary of performance if the shape of the psychometric functions is consistent over all of the conditions of interest. The slope of these functions do vary with set size (e.g., Palmer et al, 2000). This effect is not large, but it introduces a complication.…”

Section: Discussionmentioning

confidence: 99%

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Set-size effects for identification versus localization depend on the visual search task.

Busey¹,

Palmer²

2008

Journal of Experimental Psychology: Human Perception and Perfor

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In both behavior and neuroscience research, it is debated whether the processing of identity and location is closely bound throughout processing. One aspect of this debate is the possibly privileged processing of identity or location. For example, processing identity may have unlimited capacity, while processing location does not. The authors have investigated the possibility of such privileged processing by measuring set-size effects for a variety of identification and localization tasks. In particular, set-size effects in accuracy visual search are measured with either 1 or 2 possible targets. For 1-target tasks, set-size effects are smaller for identification than localization; for 2-target tasks, set-size effects are larger for identification than localization. The observed crossover interaction is inconsistent with a privileged processing hypothesis for either identity or location. Furthermore, this interaction is predicted by an independent channel model based on signal detection theory, in which the details of each decision determine the relative magnitude of the set-size effects. This result is consistent with the similar processing of identity and location, and it refutes the privileged processing hypothesis for either identity or location.

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Section: Discussionmentioning

confidence: 99%

“…We follow the notation commonly used in signal detection theory (D. M. Green & Swets, 1966; for more detail, see Palmer et al, 2000). The representation of each stimulus corresponds to a real-valued random variable.…”

Section: Common Notation and Assumptionsmentioning

confidence: 99%

Set-size effects for identification versus localization depend on the visual search task.

Busey¹,

Palmer²

2008

Journal of Experimental Psychology: Human Perception and Perfor

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“…Perhaps object recognition is accomplished by a parallel process that is capable of processing many items at once. Different types of parallel process can be devised that will produce the same patterns of data that led Treisman and others to propose a serial selfterminating search [13].…”

Section: Trends In Cognitive Sciencesmentioning

confidence: 99%

Moving towards solutions to some enduring controversies in visual search

Wolfe

2003

Trends in Cognitive Sciences

244

191

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How do we find a target item in a visual world filled with distractors? A quarter of a century ago, in her influential 'Feature Integration Theory (FIT)', Treisman proposed a two-stage solution to the problem of visual search: a preattentive stage that could process a limited number of basic features in parallel and an attentive stage that could perform more complex acts of recognition, one object at a time. The theory posed a series of problems. What is the nature of that preattentive stage? How do serial and parallel processes interact? How does a search unfold over time? Recent work has shed new light on these issues.Visual search is one of those things we do all day, every day, from finding milk in the refrigerator to locating our car in the car-park. We pay others to do it at airport security checks and in radiology laboratories and, in the past quarter of a century, we have done a great deal of it in our research laboratories. Laboratory search tasks ask the observer to find and/or identify a target item among some number of distractor items. The core empirical fact that needs explanation is that some search tasks are easy and others are difficult (see Fig. 1). We assume that, if we could successfully describe the rules that govern human search behavior, we would be able to improve performance in critical applied search tasks and to offer suggestions to those trying to build machines that might do our search tasks for us. Visual search is also an experimentally tractable way to study selective attention, and it is increasingly clear that any useful theory of visual perception will require an understanding of the role of attention.Treisman's feature integration theory Visual search and the role of attention in search has been much discussed in recent literature (see [1][2][3][4][5] for reviews). This article will concentrate on several issues growing out of Anne Treisman's seminal Feature Integration Theory (FIT) [6]. It would be a great disservice to many other researchers to label FIT as the sole 'big bang' of the visual search universe. However, it does serve well as an organizing principle for a brief review of some interesting and long-running controversies.The original FIT proposed that visual search tasks could be dichotomized into 'preattentive' and 'attentive' categories. Preattentive processing was held to occur in parallel across most or all of the visual field in a single step and to be limited to a small set of basic features like color, size, motion, and orientation. Thus, you could preattentively find a red item among green. Operationally, preattentive search for a target defined by a single basic feature would produce reaction times (RTs) independent of the number of items in the display (set size). Thus, the slope of the function relating RT to set size would be near zero. Other tasks, like a search for a randomly oriented 'T' among 'L's could not be performed preattentively. Attentive processing was presumed to marshal the more extensive perceptual capabilities required to 'bind' features ...

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“…The importance of stimulus discriminability is well established in the visual search literature and has been incorporated into major theoretical frameworks of visual search (e.g., Duncan & Humphreys, 1989;Palmer, Verghese, & Pavel, 2000;Treisman, 1991;Wolfe, Cave, & Franzel, 1989;Wolfe, 1994). Numerous previous studies have demonstrated that detecting a search target becomes more difficult with increased similarity (i.e., lower discriminability) between the target item and the distractors (e.g., Nagy & Sanchez, 1990;Neisser, 1967;Pashler, 1987;Rayner & Fisher, 1987).…”

Section: Current Studymentioning

confidence: 99%

Guidance of eye movements during conjunctive visual search: The distractor-ratio effect.

Shen¹,

Reingold²,

Pomplun³

2003

Canadian Journal of Experimental Psychology / Revue canadienne

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The distractor-ratio effect refers to the finding that search performance in a conjunctive visual search task depends on the relative frequency of two types or subsets of distractors when the total number of items in a display is fixed. Previously, Shen, Reingold, and Pomplun (2000) examined participants' patterns of eye movements in a distractor-ratio paradigm and demonstrated that on any given trial saccadic endpoints were biased towards the smaller subset of distractors and participants flexibly switched between different subsets across trials. The current study explored the boundary conditions of this tendency to flexibly search through a smaller subset of distractors by examining the influence of several manipulations known to modulate search efficiency, including stimulus discriminability (Experiment 1), within-dimension versus crossdimension conjunction search and distractor heterogeneity (Experiment 2). The results indicated that the flexibility of visual guidance and saccadic bias exemplified by the distractor-ratio effect is a robust phenomenon that mediates search efficiency by adapting to changes in the relative informativeness of stimulus dimensions and features.

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The psychophysics of visual search

Cited by 423 publications

References 147 publications

Set-size effects for identification versus localization depend on the visual search task.

Set-size effects for identification versus localization depend on the visual search task.

Moving towards solutions to some enduring controversies in visual search

Guidance of eye movements during conjunctive visual search: The distractor-ratio effect.

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