Serial and parallel processing of visual feature conjunctions

Nakayama, Ken; Silverman, Gerald

doi:10.1038/320264a0

Cited by 831 publications

(609 citation statements)

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“…However, most researchers have abandoned it (e.g. Wolfe, 1998a), as evidence accumulated to suggest that conjunction search can sometimes be quite efficient (Nakayama & Silverman, 1986) and that (as mentioned above), feature search can be inefficient when targets and distractors are very similar (Carter, 1982;Carter & Carter, 1981;Nagy & Sanchez, 1990). In addition, as is well known, sizable display set size slopes might be predicted by either a serial search or a limited-capacity parallel search in which processing is always parallel, but worsens when display set size increases (Townsend, 1976(Townsend, , 1990Wolfe, 1998a).…”

Section: Attentional Capacity Limits and The Serial/parallel Dichotomymentioning

confidence: 99%

Attention capacity and task difficulty in visual search

2005

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When a visual search task is very difficult (as when a small feature difference defines the target), even detection of a unique element may be substantially slowed by increases in display set size. This has been attributed to the influence of attentional capacity limits. We examined the influence of attentional capacity limits on three kinds of search task: difficult feature search (with a subtle featural difference), difficult conjunction search, and spatial-configuration search. In all 3 tasks, each trial contained sixteen items, divided into two eight-item sets. The two sets were presented either successively or simultaneously. Comparison of accuracy in successive versus simultaneous presentations revealed that attentional capacity limitations are present only in the case of spatialconfiguration search. While the other two types of task were inefficient (as reflected in steep search slopes), no capacity limitations were evident. We conclude that the difficulty of a visual search task affects search efficiency but does not necessarily introduce attentional capacity limits. q

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Section: Attentional Capacity Limits and The Serial/parallel Dichotomymentioning

confidence: 99%

Attention capacity and task difficulty in visual search

2005

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“…FIT has been modified over the years since its introduction 37 , but the proposition that spatial attention is crucial for correct feature binding has remained. The theory has been the topic of some debate, especially regarding the question of whether features are processed in a qualitatively or quantitatively different way from conjunctions [38][39][40] . But the fact that spatial attentional deficits disrupt binding, while leaving feature detection relatively intact, lends strong support to the premise that feature detection and conjunction detection occur in qualitatively different ways.…”

Section: Space and Bindingmentioning

confidence: 99%

Binding, spatial attention and perceptual awareness

2003

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The world is experienced as a unified whole, but sensory systems do not deliver it to the brain in this way. Signals from different sensory modalities are initially registered in separate brain areas -even within a modality, features of the sensory mosaic such as colour, size, shape and motion are fragmented and registered in specialized areas of the cortex. How does this information become bound together in experience? Findings from the study of abnormal binding -for example, after stroke -and unusual binding -as in synaesthesia -might help us to understand the cognitive and neural mechanisms that contribute to solving this 'binding problem'.Different areas of the cortex receive sensory information through different receptors (for example, the eyes, ears or touch receptors), showing that different areas of the cortex respond to different features of the sensory mosaic. Investigations of multimodal integration have a long history, but a particularly interesting binding problem arose when reliable evidence began to emerge that, within the brain, different areas are specialized for encoding different features of the visual modality, such as colour, shape, size and motion in vision 1 . Electrophysiological recordings from monkey cortices showed that visual neurons in different areas responded with different strengths to different features 2 . This specialization has received support from functional imaging studies in humans 3 . Moreover, this evidence is consistent with more than a hundred years of neuropsychological reports that lesions in different areas of the human brain can result in relatively isolated deficits in visual processing -for example, ACHROMATOPSIA or visual NEGLECT 4,5 . This modular organization of the brain led to the question of how features that are registered separately are reunited to produce our unified experience of the world 6,7 . Some researchers have argued that this type of 'binding problem' is not a problem at all 8,9 , but recent evidence has shown that it can become a real problem in everyday life when certain areas of the brain are no longer functioning 10 .In this review, I will discuss evidence -from both normal perceivers and neurological patients -that binding features within vision is a problem in humans, and is not just a theoretical construct. I will then describe the role that spatial attention is believed to have in this type of binding, emphasizing the spatial functions of the parietal lobes 11 . Finally, I will explore how binding might change if two or more specialized FEATURE MAPS were to merge. This final issue has been approached within a cognitive neuroscience perspective by testing shape/colour synaesthetes -otherwise normal individuals who perceive internally generated colours (induced by particular visual shapes) as if they were being received by sensory receptors (so that the colours are perceived as 'out there') 12 . For instance, the letter A might induce a certain shade of blue. It has been hypothesized that synaesthesia results from developmentally a...

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“…The red signal in traffic lights is one such example (Bugalski, 1967). To demonstrate the link between spatial attention, color, and depth perception, Nakayama and Silverman (1986) have shown that the visual detection of targets defined by conjunctions of color and depth in a visual search task is faster than the detection of targets defined by a single attribute. The implications of a correlation between perceived depth in geometric configurations and selective visual attention are discussed further by Nakayama, Shimojo, and Ramachandran (1990).…”

Section: The Contribution Of Color Stereopsismentioning

confidence: 99%

“…Then, a strong luminance or color cue combined with a strong geometric cue should produce shorter response latencies than a weaker luminance or color cue combined with a weaker geometric cue. Measuring response latencies to probe attentional mechanisms has proved successful in visual search experiments (e.g., Nakayama & Silverman, 1986), showing that certain combinations of visual cues produce significantly shorter response latencies than others in a given task context. Such effects are commonly explained in terms of facilitation or inhibition of attentional selection (e.g., Goolsby & Suzuki, 2001).…”

Section: The Contribution Of Color Stereopsismentioning

confidence: 99%

“…To test for effects of background luminance previously observed in color stereopsis, we presented isoluminant color pairs on dark and light backgrounds. Finally, to look for a possible correlation between selective visual attention and perceived depth, suggested by findings on visual search for targets defined by color and depth (e.g., Nakayama & Silverman, 1986), we analyzed response times for ''near'' responses in the two experiments.…”

Section: The Contribution Of Color Stereopsismentioning

confidence: 99%

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Interaction of color and geometric cues in depth perception: When does ?red? mean ?near??

Guibal

Dresp

2004

Psychological Research

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Luminance and color are strong and self-sufficient cues to pictorial depth in visual scenes and images. The present study investigates the conditions under which luminance or color either strengthens or overrides geometric depth cues. We investigated how luminance contrast associated with the color red and color contrast interact with relative height in the visual field, partial occlusion, and interposition to determine the probability that a given figure presented in a pair is perceived as ''nearer'' than the other. Latencies of ''near'' responses were analyzed to test for effects of attentional selection. Figures in a pair were supported by luminance contrast (Experiment 1) or isoluminant color contrast (Experiment 2) and combined with one of the three geometric cues. The results of Experiment 1 show that the luminance contrast of a color (here red), when it does not interact with other colors, produces the same effects as achromatic luminance contrasts. The probability of ''near'' increases with the luminance contrast of the color stimulus, the latencies for ''near'' responses decrease with increasing luminance contrast. Partial occlusion is found to be a strong enough pictorial cue to support a weaker red luminance contrast. Interposition cues lose out against cues of spatial position and partial occlusion. The results of Experiment 2, with isoluminant displays of varying color contrast, reveal that red color contrast on a light background supported by any of the three geometric cues wins over green or white supported by any of the three geometric cues. On a dark background, red color contrast supported by the interposition cue loses out against green or white color contrast supported by partial occlusion. These findings reveal that color is not an independent depth cue, but is strongly influenced by luminance contrast and stimulus geometry. Systematically shorter response latencies for stronger ''near'' percepts demonstrate that selective visual attention reliably detects the most likely depth cue combination in a given configuration.

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Serial and parallel processing of visual feature conjunctions

Cited by 831 publications

References 8 publications

Attention capacity and task difficulty in visual search

Attention capacity and task difficulty in visual search

Binding, spatial attention and perceptual awareness

Interaction of color and geometric cues in depth perception: When does ?red? mean ?near??

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