Target Color Research Articles

Task-Irrelevant Features in Visual Working Memory Influence Covert Attention: Evidence from a Partial Report Task.

Selecting a target based on a representation in visual working memory (VWM) affords biasing covert attention towards objects with memory-matching features. Recently, we showed that even task-irrelevant features of a VWM template bias attention. Specifically, when participants had to saccade to a cued shape, distractors sharing the cue’s search-irrelevant color captured the eyes. While a saccade always aims at one target location, multiple locations can be attended covertly. Here, we investigated whether covert attention is captured similarly as the eyes. In our partial report task, each trial started with a shape-defined search cue, followed by a fixation cross. Next, two colored shapes, each including a letter, appeared left and right from fixation, followed by masks. The letter inside that shape matching the preceding cue had to be reported. In Experiment 1, either target, distractor, both, or no object matched the cue’s irrelevant color. Target-letter reports were most frequent in target-match trials and least frequent in distractor-match trials. Irrelevant cue and target color never matched in Experiment 2. Still, participants reported the distractor more often to the target’s disadvantage, when cue and distractor color matched. Thus, irrelevant features of a VWM template can influence covert attention in an involuntarily object-based manner when searching for trial-wise varying targets.

Humans can efficiently look for but not select multiple visual objects.

The human brain recurrently prioritizes task-relevant over task-irrelevant visual information. A central question is whether multiple objects can be prioritized simultaneously. To answer this, we let observers search for two colored targets among distractors. Crucially, we independently varied the number of target colors that observers anticipated, and the number of target colors actually used to distinguish the targets in the display. This enabled us to dissociate the preparation of selection mechanisms from the actual engagement of such mechanisms. Multivariate classification of electroencephalographic activity allowed us to track selection of each target separately across time. The results revealed only small neural and behavioral costs associated with preparing for selecting two objects, but substantial costs when engaging in selection. Further analyses suggest this cost is the consequence of neural competition resulting in limited parallel processing, rather than a serial bottleneck. The findings bridge diverging theoretical perspectives on capacity limitations of feature-based attention.

Acoustophoretic volumetric displays using a fast-moving levitated particle

Displays have revolutionized the way we work and learn, and thus, the development of display technologies is of paramount importance. The possibility of a free-space display in which 3D graphics can be viewed from 360° without obstructions is an active area of research—holograms or lightfield displays can realize such a display, but they suffer from clipping and a limited field of view. Here, we use a phased array of ultrasonic emitters to realize a volumetric acoustophoretic display in which a millimetric particle is held in midair using acoustic radiation forces and moved rapidly along a 3D path. Synchronously, a light source illuminates the particle with the target color at each 3D position. We show that it is possible to render simple figures in real time (10 frames per second) as well as raster images at a lower frame rate. Additionally, we explore the dynamics of a fast-moving particle inside a phased-array levitator and identify potential sources of degradation in image quality. The dynamics are nonlinear and lead to distortion in the displayed images, and this distortion increases with drawing speed. The created acoustophoretic display shows promise as a future form of display technology.

Cueing color imagery: A critical analysis of imagery-perception congruency effects.

The relation between mental imagery and visual perception is a long debated topic in experimental psychology. In a recent study, Wantz, Borst, Mast, and Lobmaier (2015) demonstrated that color imagery could benefit color perception in a task that involved generating imagery in response to a cue prior to a forced-choice color discrimination task. Here, we scrutinized whether the method of Wantz et al. warrants strong inferences about the role of color imagery in color perception. In Experiments 1-3, we demonstrate that the imagery effect reported by Wantz et al. does replicate nicely using their method but does not occur when cue-target contingencies and a redundancy between the imagery and response dimensions are removed from their method. In Experiments 4-6, we explored cued imagery effects further using a method in which the cued imagery dimension was orthogonal to the response dimension. The results of these experiments demonstrate that a compelling endogenously cued imagery effect does not occur for lone targets but does occur for singleton color targets embedded amid homogenous color distractors. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Alpha‐band desynchronization reflects memory‐specific processes during visual change detection

Recent work investigating physiological mechanisms of working memory (WM) has revealed that modulation of alpha and beta frequency bands within the EEG plays a key role in WM storage. However, the nature of that role is unclear. In the present study, we examined event-related desynchronization of alpha and beta (α/β-ERD) elicited by visual tasks with and without a memory component to measure the impact of a WM demand on this electrophysiological marker. We recorded EEG from 60 healthy participants while they completed three variants on a typical change detection task: one in which participants passively viewed the sample array, passive (WM-); one in which participants viewed and attended the sample array in search of a target color but did not memorize the colors, active (WM-); and one in which participants encoded, attended to, and memorized the sample array, active (WM+). Replicating previous findings, we found that active (WM+) elicited robust α/β-ERD in frontal and posterior electrode clusters and that α-ERD was significantly associated with WM capacity. By contrast, α/β-ERD was significantly smaller in the passive (WM-) and active (WM-) tasks, which did not consistently differ from one another. Furthermore, no such relationship was observed between WM capacity and desynchronization in the passive (WM-) or active (WM-) tasks. Taken together, these results suggest that α-ERD during memory formation reflects a memory-specific process such as consolidation or maintenance, rather than serving a generalized role in perceptual gating or engagement of attention.

Conjunction search: Can we simultaneously bias attention to features and relations?

Attention allows selection of sought-after objects by tuning attention in a top-down manner to task-relevant features. Among other possible search modes, attention can be tuned to the exact feature values of a target (e.g., red, large), or to the relative target feature (e.g., reddest, largest item), in which case selection is context dependent. The present study tested whether we can tune attention simultaneously to a specific feature value (e.g., specific size) and a relative target feature (e.g., relative color) of a conjunction target, using a variant of the spatial cueing paradigm. Tuning to the specific feature of the target was encouraged by randomly presenting the conjunction target in a varying context of nontarget items, and feature-specific versus relational tuning was assessed by briefly presenting conjunction cues that either matched or mismatched the relative versus physical features of the target. The results showed that attention could be biased to the specific size and the relative color of the conjunction target or vice versa. These results suggest the existence of local and relatively low-level attentional control mechanisms that operate independently of each other in separate feature dimensions (color, size) to choose the best search strategy in line with current top-down goals.

Hearing words changes color perception: Facilitation of color discrimination by verbal and visual cues.

As part of learning some languages, people learn to name colors using categorical labels such as "red," "yellow," and "green." Such labeling clearly facilitates communicating about colors, but does it also impact color perception? We demonstrate that simply hearing color words enhances categorical color perception, improving people's accuracy in discriminating between simultaneously presented colors in an untimed task. Immediately after hearing a color word participants were better able to distinguish between colors from the named category and colors from nearby categories. Discrimination between typical and atypical category members was also enhanced. Verbal cues slightly decreased discrimination accuracy between two typical shades of the named color. In contrast to verbal cues, a preview of the target color, an arguably more informative cue, failed to yield any changes to discrimination accuracy. The finding that color words strongly affect color discrimination accuracy suggests that categorical color perception may be caused by color representations being augmented in-the-moment by language. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Motivation System for Students to Learn Control Engineering and Image Processing

Our aim was to motivate students to study control engineering and image processing. To this end, we designed a motivation system based on the ARCS model, developed by John M. Keller, to motivate learners. We used a drone as the control object. The ARCS model consists of four steps: attention, relevance, confidence, and satisfaction. The control process is performed by capturing images from the drone’s camera on a PC via Wi-Fi, and detecting a target color using an image processing technique. Then, the PC sends the control inputs from a PID controller back to the drone to track the target color by keeping it at the center of the images. With this system, students can gain knowledge on control engineering and image processing by tuning the parameters of PID controller and image processing, and observing the responses of the drone. To assess the effectiveness of our system, we requested 150 first-grade technical college students, who had no prior knowledge of control engineering and image processing, to attend our lecture. After the lecture, the students were asked to answer a questionnaire on their interests. The result demonstrated that over 80% of them expressed an interest in learning these two techniques.

Colour recipe prediction using ant colony algorithm: principle of resolution and analysis of performances

AbstractThis paper presents a new method for colour recipe prediction using ant colony optimisation. Three reactive dyes, namely CI Reactive Yellow 145, CI Reactive Red 238 and CI Reactive Blue 235, were used for colour formulation. Samples of 100% cotton fabrics were used for dyeing. The objective was to assure, control and optimise the colour formulation step by determining the dyes to be applied and their respective concentrations to reproduce the desired shades. The criterion of optimisation is to minimise the colour differences [Colour Measurement Committee (2:1)] between the target colour and the colour obtained by the proposed recipe. Errors between the proposed recipe and actual concentrations are also evaluated. The developed algorithm showed good performances with small colour differences between the target and reproduced colours (all lower than 0.7).

How Does Spatial Attention Influence the Probability and Fidelity of Colour Perception?

Existing research has found that spatial attention alters how various stimulus properties are perceived (e.g., luminance, saturation), but few have explored whether it improves the accuracy of perception. To address this question, we performed two experiments using modified Posner cueing tasks, wherein participants made speeded detection responses to peripheral colour targets and then indicated their perceived colours on a colour wheel. In E1, cues were central and endogenous (i.e., prompted voluntary attention) and the interval between cues and targets (stimulus onset asynchrony, or SOA) was always 800 ms. In E2, cues were peripheral and exogenous (i.e., captured attention involuntarily) and the SOA varied between short (100 ms) and long (800 ms). A Bayesian mixed-model analysis was used to isolate the effects of attention on the probability and the fidelity of colour encoding. Both endogenous and short-SOA exogenous spatial cueing improved the probability of encoding the colour of targets. Improved fidelity of encoding was observed in the endogenous but not in the exogenous cueing paradigm. With exogenous cues, inhibition of return (IOR) was observed in both RT and probability at the long SOA. Overall, our findings reinforce the utility of continuous response variables in the research of attention.

Interactive influences of color attributes on color perception bias

Graphic user interfaces and information visualization use color to represent qualitative or quantitative information. The interaction between adjacent colors leads to perceptual bias, known as simultaneous color contrast, and implicitly distort the understanding of visualized information presentation. To investigate the effect of simultaneous color contrast, we conduct two empirical experiments, in both theoretical and application settings, using a set of random target/proximal combinations of colors in the CIEL*a*b* color space. The perception bias of a target color, induced by its surround, is measured. Linear regression analysis indicates that both a high saturation of the proximal color and a high a*/low b* value of the target color cause a strong simultaneous color contrast (i.e., high perception bias). A moderating effect analysis indicates that a* value/b* value of the target color moderates the influence of the saturation of the proximal color on the perception bias. For example, controlling the saturation of the proximal color, the more reddish/yellowish the target color is, the more alleviated the perceptual bias is.

"Individual differences in search and monitoring for color targets in dynamic visual displays": Correction to Muhl-Richardson et al. (2018).

Reports an error in "Individual differences in search and monitoring for color targets in dynamic visual displays" by Alex Muhl-Richardson, Hayward J. Godwin, Matthew Garner, Julie A. Hadwin, Simon P. Liversedge and Nick Donnelly (Journal of Experimental Psychology: Applied, 2018[Dec], Vol 24[4], 564-577). In the article, there was a formatting error in table 2 on page 573. The corrected table is presented in the erratum, and the online version of this article has been corrected. (The following abstract of the original article appeared in record 2018-04009-001.) Many real-world tasks now involve monitoring visual representations of data that change dynamically over time. Monitoring dynamically changing displays for the onset of targets can be done in two ways: detecting targets directly, post-onset, or predicting their onset from the prior state of distractors. In the present study, participants' eye movements were measured as they monitored arrays of 108 colored squares whose colors changed systematically over time. Across three experiments, the data show that participants detected the onset of targets both directly and predictively. Experiments 1 and 2 showed that predictive detection was only possible when supported by sequential color changes that followed a scale ordered in color space. Experiment 3 included measures of individual differences in working memory capacity (WMC) and anxious affect and a manipulation of target prevalence in the search task. It found that predictive monitoring for targets, and decisions about target onsets, were influenced by interactions between individual differences in verbal and spatial WMC and intolerance of uncertainty, a characteristic that reflects worry about uncertain future events. The results have implications for the selection of individuals tasked with monitoring dynamic visual displays for target onsets. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Splitting the attentional spotlight? Evidence from attentional capture by successive events

ABSTRACTMust attention be disengaged from a location before it can be moved to another? We addressed this question in four experiments. Participants searched for a target defined by its colour. The search display followed either one or two successive singleton cues that were expected to capture attention because they were in the target colour. We found a spatial benefit at the location of the first cue even though attention had been shifted to the location of the second cue. However, this benefit was smaller than when the second cue had been absent. These findings suggest that attention can be directed to a new location before it is entirely disengaged from its previous locus. We tested and rejected alternative interpretations, according to which this residual spatial effect resulted from occasional failures of attentional capture by the second cue, or from variability of the speed at which attention was shifted from one cue to the other. Taken together, our findings suggest that shifting attention from one location to another results in two simultaneous foci of attention for at least 300 ms. We discuss the possibility that the residual spatial benefits observed here may reflect pre-attentive tagging rather than parallel allocation of a limited resource to two separate locations.

The allocation of resources in visual working memory and multiple attentional templates.

In a visual search task, sensory input is matched to a representation of the search target in visual working memory (VWM). This representation is referred to as attentional template. We investigated the conditions that allow for more than a single attentional template. The attentional template of color targets was measured by means of the contingent attentional capture paradigm. We found that attentional templates did not differ between search with 1 and 2 memorized target colors, suggesting that dual target search allowed for multiple attentional templates. In the same paradigm, we asked participants to memorize target and distractor color with equal precision. Both were presented before the search task. An attentional template was set up for the target, but not for the distractor color, suggesting that keeping a color in VWM does not automatically result in the creation of multiple attentional templates. Importantly, the precision of recall of the distractor color was worse than the precision of recall of the target color, regardless of instructions, suggesting that participants always allocated fewer VWM resources to the distractor color. Thus, 2 attentional templates may be set up, but only when the 2 colors receive an equal amount of resources in VWM (i.e., in dual target search). In contrast, when 1 item is deprioritized because of task demands, it receives fewer resources in VWM and multiple attentional templates cannot be established. Thus, unequal roles in the search task prevented the simultaneous operation of multiple attentional templates in VWM. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Different shape and color targets detection using auto indexing images in computer vision system

One of the main challenges in computer vision is to determine the number of different types, shapes, locations and color targets within the image plane for use in computer control systems. In this study, an algorithm introduced to detect the number of targets (one or two), their shapes (square or circle) and colors (red, green or blue). A new technique presented as a digital indexing code table to present the studied color targets images. The indexing table technique depends on decimal and binary numbers. In this study, there were 42 different cases represents all the input images. There is a special case considered for the similarity of input images in case it has the same shape and color, but a change in rotation and space between two image targets. This solved using referencing to indicate the same target in each case. Thus, the classification results were 100% for the presented algorithm for all input cases.

Barriers block the effect of joint attention on working memory: Perspective taking matters.

Joint focus of attention between two individuals can influence the way that observers attend, encode, and value items. Using a nonpredictive gaze cuing task we previously found that working memory (WM) was better for jointly attended (validly cued) versus invalidly cued colored squares. Here we examine whether this influence of gaze on WM is driven by observers sharing the perspective of the face cue (mental state account), or simply by increased attention to the cued location (social attention account). To manipulate perspective taking, a closed barrier obstructed the cue face's view of the memoranda, while an open barrier allowed the cue face to "see" the colors. A central cue face flanked by two identical barriers looked left or right, followed 500 ms later by colored squares for encoding which appeared equally often in the validly and invalidly cued locations. After a blank 1,000 ms maintenance interval, participants stated whether a probe color was present or not in the preceding display. When the barrier was open, WM was significantly impaired for invalidly versus validly cued items. When the barrier was closed, the effect of gaze cues on WM was abolished. In contrast, further experiments showed a significant cuing effect on the speed of simple target localization and color discrimination regardless of barrier type. These findings support the mental state account of joint attention in WM, whereby the attentional focus of another alters WM via higher level engagement with the second person perspective. A goal-specific model of perspective taking is proposed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

색면추상을 적용한 루이스 바라간과 제임스 터렐의 거대색채 분석

Currently, the field of visual arts has expanded its scope and meaning by the development of media technology. Nevertheless, form and colors are the main means to express the value system pursued by painters and architects. Among them, the overwhelming color is used as a tool to determine the nuance of the art itself or the space where the art is installed. Especially the vast color of the visual arts has a great influence on synesthesia effect. In other words, overwhelming color is a transition of sensations that loosens the space between the interior and exterior of the space - the work and the workspace. Therefore, overwhelming color can not be seen only as a result of the physical energy of light. Therefore, this study examines the works of Luis Barragán and James Turrell, who actively utilize the features of color facial abstraction and apply gigantic colors to the nuances of space. The characteristics of the used by them are as follows. First, overwhelming color does not aim at the coloring and harmony of the target color as the expression element of the artist. That is, the form is collapsed, newly completed, and has abstract properties of cancellation. Second, this do not seek formative formality by means of color. Thus, the macroscopic colors are juxtaposed or collided with each other and have a hybridization characteristic of Non-figurative. Third, this extend color to spaces outside objects. Especially, the weight of the overwhelming color has the unified characteristic of the borderless due to the mystique and awe.

Competitive binding predicts nonlinear responses of olfactory receptors to complex mixtures

In color vision, the quantitative rules for mixing lights to make a target color are well understood. By contrast, the rules for mixing odorants to make a target odor remain elusive. A solution to this problem in vision relied on characterizing receptor responses to different wavelengths of light and subsequently relating these responses to perception. In olfaction, experimentally measuring receptor responses to a representative set of complex mixtures is intractable due to the vast number of possibilities. To meet this challenge, we develop a biophysical model that predicts mammalian receptor responses to complex mixtures using responses to single odorants. The dominant nonlinearity in our model is competitive binding (CB): Only one odorant molecule can attach to a receptor binding site at a time. This simple framework predicts receptor responses to mixtures of up to 12 monomolecular odorants to within 15% of experimental observations and provides a powerful method for leveraging limited experimental data. Simple extensions of our model describe phenomena such as synergy, overshadowing, and inhibition. We demonstrate that the presence of such interactions can be identified via systematic deviations from the competitive-binding model.

Macaque dorsal premotor cortex exhibits decision-related activity only when specific stimulus\u2013response associations are known

How deliberation on sensory cues and action selection interact in decision-related brain areas is still not well understood. Here, monkeys reached to one of two targets, whose colors alternated randomly between trials, by discriminating the dominant color of a checkerboard cue composed of different numbers of squares of the two target colors in different trials. In a Targets First task the colored targets appeared first, followed by the checkerboard; in a Checkerboard First task, this order was reversed. After both cues appeared in both tasks, responses of dorsal premotor cortex (PMd) units covaried with action choices, strength of evidence for action choices, and RTs— hallmarks of decision-related activity. However, very few units were modulated by checkerboard color composition or the color of the chosen target, even during the checkerboard deliberation epoch of the Checkerboard First task. These findings implicate PMd in the action-selection but not the perceptual components of the decision-making process in these tasks.

Temporal integration and attentional selection of color and contrast target pairs in rapid serial visual presentation

Performance in a dual target rapid serial visual presentation task was investigated, dependent on whether the color or the contrast of the targets was the same or different. Both identification accuracy on the second target, as a measure of temporal attention, and the frequency of temporal integration were measured. When targets had a different color (red or blue), overall identification accuracy of the second target and identification accuracy of the second target at Lag 1 were both higher than when targets had the same color. At the same time, increased temporal integration of the targets at Lag 1 was observed in the different color condition, even though actual (non-integrated) single targets never consisted of multiple colors. When the color pairs were made more similar, so that they all fell within the range of a single nominal hue (blue), these effects were not observed. Different findings were obtained when contrast was manipulated. Identification accuracy of the second target was higher in the same contrast condition than in the different contrast condition. Higher identification accuracy of both targets was furthermore observed when they were presented with high contrast, while target contrast did not influence temporal integration at all. Temporal attention and integration were thus influenced differently by target contrast pairing than by (categorical) color pairing. Categorically different color pairs, or more generally, categorical feature pairs, may thus afford a reduction in temporal competition between successive targets that eventually enhances attention and integration.