The achromatic mechanism and mechanisms tuned to chromaticity and luminance in visual search

Nagy, Allen L.; Winterbottom, Marc

doi:10.1364/josaa.17.000369

Cited by 16 publications

(12 citation statements)

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“…Values of SNR were computed over all angles in the color space assuming that color contrasts are encoded roughly uniformly by linear mechanisms tuned to different directions, and thus that the contrast is weighted by the cosine of the angle between the element’s axis and the projected axis. Again this is consistent with the selectivity of the color search for multiple color directions observed in the results above and in previous studies (Bauer et al, 1998; D’Zmura, 1991; Nagy & Thomas, 2003; Nagy & Winterbottom, 2000). We further assumed that each axis was encoded by separate “on” and “off” pathways so that background elements only contributed to the noise when they had the same sign as the target (e.g., so that luminance increments were not affected by luminance decrements).…”

Section: Resultssupporting

confidence: 93%

“…Specifically, as with the backgrounds along different chromatic axes, the salience of targets along each color–luminance axis increased as they deviated from the background axis. This is consistent with studies from adaptation, masking, and visual search suggesting that luminance and chromatic contrast are not processed independently (Gegenfurtner & Kiper, 1992; Hansen & Gegenfurtner, 2006; Nagy & Winterbottom, 2000; Webster & Mollon, 1991, 1993). For the present results, there is a strong asymmetry between the response times for the luminance and chromatic targets, with faster detection for targets with luminance contrast.…”

Section: Resultssupporting

confidence: 90%

“…Importantly, this effect was found to hold for any direction in the space, including different chromatic axes or different combinations of luminance and color. This suggests that visual search depends on mechanisms that can be tuned to many different directions in the volume of color space (Bauer et al, 1996; D’Zmura, 1991; Nagy & Thomas, 2003; Nagy & Winterbottom, 2000). …”

Section: Introductionmentioning

confidence: 99%

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Adaptation and visual salience

et al. 2010

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We examined how the salience of color is affected by adaptation to different color distributions. Observers searched for a color target on a dense background of distractors varying along different directions in color space. Prior adaptation to the backgrounds enhanced search on the same background while adaptation to orthogonal background directions slowed detection. Advantages of adaptation were seen for both contrast adaptation (to different color axes) and chromatic adaptation (to different mean chromaticities). Control experiments, including analyses of eye movements during the search, suggest that these aftereffects are unlikely to reflect simple learning or changes in search strategies on familiar backgrounds, and instead result from how adaptation alters the relative salience of the target and background colors. Comparable effects were observed along different axes in the chromatic plane or for axes defined by different combinations of luminance and chromatic contrast, consistent with visual search and adaptation mediated by multiple color mechanisms. Similar effects also occurred for color distributions characteristic of natural environments with strongly selective color gamuts. Our results are consistent with the hypothesis that adaptation may play an important functional role in highlighting the salience of novel stimuli by discounting ambient properties of the visual environment.

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Section: Resultssupporting

confidence: 93%

Section: Resultssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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Adaptation and visual salience

et al. 2010

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“…As an example, many previous psychophysical studies of human color vision have suggested that the cardinal axes in color space represent independent color-coding mechanisms under many conditions (e.g., Nagy, 1999;Nagy & Winterbottom, 2000). Comparisons of the results in Experiments 1 and 2 and the results of Experiment 3 both suggest that signals in different cardinal color mechanisms interact to determine search performance.…”

Section: Discussionmentioning

confidence: 83%

The effect of background color on asymmetries in color search

Rosenholtz¹,

Nagy

Bell

2004

Journal of Vision

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Many previous studies have shown that background color affects the discriminability and appearance of color stimuli. However, research on visual search has not typically considered the role that the background may play. Rosenholtz (2001a) has suggested that color search asymmetries result from the relationship between the stimuli and the background. Here we test the hypothesis that background color should have an effect on asymmetries in visual search based on color, using searches for color stimuli on different colored backgrounds. Observers searched for a single known target stimulus among homogeneous distractor stimuli. The target stimulus differed from the distractors only in chromaticity, but targets and distractors both differed from the backgrounds in luminance so that they were easily visible regardless of chromaticity. Target/distractor pairs differed primarily in saturation (Experiments 1, 2, & 3) or in hue (Experiment 4). Each member of each pair of colors served as target and distractor color on both achromatic and red backgrounds. When the stimuli were presented on an achromatic background, response times were shorter when the more saturated member of each pair of colors served as the target color. When the same stimuli were presented on a red background, the asymmetry was either reversed or abolished. When target and distractors differed in hue, there was little asymmetry on the achromatic background but a sizable asymmetry for some color pairs on the red background. On both backgrounds, the magnitude of the asymmetry varied with the difference between the stimulus colors and the background color. Results confirm that asymmetries in color search are dependent on the relationship between the stimulus colors and the background color. Two candidate models are suggested that show promise in predicting these experimental results: Rosenholtz' saliency model (1999, 2001a) and a modification to signal detection theory models in which the observation noise is proportional to the difference between target/distractor color and background color.

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“…This pattern has been found in particular if the object is relevant for the task (Yantis and Egeth 1999), but even persists if attending to the object that pops-out is known to be irrelevant and disadvantageous to the performance of the task (e.g., Pashler 1988;Theeuwes 1991Theeuwes , 1992. Especially, unique colors (e.g., Nagy and Winterbottom 2000;Galfano 2000, 2001;Turatto et al 2004) and luminance contrasts (Enns et al 2001) seem very effective at capturing attention.…”

Section: Theoretical Accounts Of the Effect Of Cueing On Perceptual Amentioning

confidence: 94%

Towards a Framework for Attention Cueing in Instructional Animations: Guidelines for Research and Design

et al. 2009

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This paper examines the transferability of successful cueing approaches from text and static visualization research to animations. Theories of visual attention and learning as well as empirical evidence for the instructional effectiveness of attention cueing are reviewed and, based on Mayer's theory of multimedia learning, a framework was developed for classifying three functions for cueing: (1) selection-cues guide attention to specific locations, (2) organization-cues emphasize structure, and (3) integration-cues explicate relations between and within elements. The framework was used to structure the discussion of studies on cueing in animations. It is concluded that attentional cues may facilitate the selection of information in animations and sometimes improve learning, whereas organizational and relational cueing requires more consideration on how to enhance understanding. Consequently, it is suggested to develop cues that work in animations rather than borrowing effective cues from static representations. Guidelines for future research on attention cueing in animations are presented. Keywords Instructional animations . Cognitive load theory . Instructional designRecent advances in software and computer technology enable designers of computer-based instruction to use dynamic visualizations, such as animation and video, to help learners remember complex dynamic systems and, ultimately, understand the materials (Lowe 2004). At present, the majority of animations present information in close correspondence with the referential situation, without highlighting the information or providing cues to help learners process the material. However, manipulating the visuospatial characteristics of animations may make them more effective, just as manipulating these aspects in static

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The achromatic mechanism and mechanisms tuned to chromaticity and luminance in visual search

Cited by 16 publications

References 29 publications

Adaptation and visual salience

Adaptation and visual salience

The effect of background color on asymmetries in color search

Towards a Framework for Attention Cueing in Instructional Animations: Guidelines for Research and Design

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