Visual Search Mechanisms Research Articles

Can playing video games enhance reading skills through more efficient serial visual search mechanisms? Insights from an eye tracking study

ABSTRACT Reading disorders are associated with atypical top-down visual attention (VA) processes like reduced VA span and slower serial visual search (SVS). In contrast, expert action video game (AVG) players, known for their efficient top-down VA, exhibit improved reading abilities. It is unclear whether these benefits stem solely from AVGs or apply to other gaming experiences. To explore this, AVG players (AVGPs), players of genres excluding AVGs (VGPs), and non-players were evaluated on their VA span, and behavioural and oculomotor performance in SVS. VGPs, but not AVGPs, demonstrated enhanced performance and oculomotor behaviour in SVS compared to non-players, while both player groups showed a trend towards better VA span skills. Notably, reading-related skills were enhanced in the two player groups, but particularly more so in VGPs. These findings support the existence of potential benefits of playing video games different from classical AVGs for the development of top-down VA and reading-related abilities.

Impaired eye movements in Parkinson's disease and their relationship to top–down and bottom–up neural processing

AbstractIntroductionEye movement disorder in patients with Parkinson's disease (PD) is less likely to appear when observing complex images compared with simple images. However, in case of auditory stimuli, meaningful stimuli can promote PD movement. Thus, we measured visual search movements with an eye tracker to investigate whether visual search changes in PD depending on the meaningfulness of visual stimuli; additionally, we measured event‐related potentials (ERPs) to neurophysiologically examine visual information processing in PD.MethodsData from 11 patients with cognitively unimpaired PD and 10 neurologically healthy individuals (controls) were used in this study. We simultaneously measured eye tracking and ERPs during the observation of three types of images: operation, noun, and meaningless figures. We compared intergroup differences in visual search parameters, such as saccade count, fixation time, and saccade amplitude, as well as in ERPs vertex‐to‐vertex amplitudes and latency among P1, N1, P2, and N2 at the posterior regions. These ERPs reflect different stages of visual information processing and provide insights into the underlying neural mechanisms of visual search in PD.ResultsAll visual search parameters were consistently smaller in the PD group than in the control group, regardless of visual stimulus. The saccade count in the PD group was significantly lower than in the control group for operation and meaningless figures but not for noun figures. Further, P1 and N1 amplitudes—bottom–up processing—were smaller in PD group when viewing operation figures and N2 amplitudes—top–down processing—were larger in PD group when viewing operation and meaningless figures.ConclusionsPD's visual search movements may change depending on the meaningfulness of visual stimuli. Further, the abnormal visual search movements in PD may be due to insufficient bottom–up processing and excessive top–down processing.Plain Language SummaryParkinson's disease (PD) is a neurodegenerative disorder that can cause eye movement disorders. People with PD may have difficulty searching for and processing visual information. In this study, we investigated how meaningfulness affects visual search movements and visual information processing in people with PD. We measured eye movements and brain activity in response to different types of visual stimuli, including meaningful and meaningless images, and compared them to a group of healthy control participants. Our results showed that PD patients had fewer eye movements and different brain activity patterns compared to healthy controls, regardless of the meaningfulness of the visual stimuli. However, we also found that the meaningfulness of visual stimuli had an effect on visual search movements in PD patients. This suggests that meaningfulness can impact the way people with PD process visual information. Understanding these differences could help in the development of new therapies to improve visual processing in people with PD.

Solar photovoltaic cell model optimal parameter identification by using an improved chimp optimization algorithm

Identifying the parameters of solar photovoltaic (PV) cell models accurately and reliably is crucial for simulating, evaluating, and controlling PV systems. For this reason, we present an improved chimp optimization algorithm (IChOA) for the generation of precise and reliable solar PV cell models. As a new and improved version of the standard chimp optimization algorithm (ChOA), IChOA embeds two mutation rules in ChOA that include the elite opposition-based learning and visual search mechanism. The first rule is applied to strengthen global exploration capacity of ChOA, and the second one is utilized to enhance ChOA’s local exploitation ability (convergence accuracy). Based on the six benchmark test functions with different characteristics, the effectiveness of IChOA is evaluated by comparing to other five well-known optimization algorithms. The results suggest that IChOA offers superior performance over other competing algorithms. Finally, IChOA’s performance is confirmed through optimizing parameters for three widely employed mathematical models, specifically the single diode model, the double diode model, and the multi-cell PV modules. The findings prove the excellent performance of the suggested approach.

Visual expertise is more than meets the eye: an examination of holistic visual processing in radiologists and architects.

One of the dominant behavioral markers of visual-expert search strategy, holistic visual processing (HVP), suggests that experts process information from a larger region of space in conjunction with a more focused gaze pattern to improve search speed and accuracy. To date, extant literature suggests that visual search expertise is domain specific, including HVP and its associated behaviors. The current study is the first to use eye tracking to directly measure the HVP strategies of two expert groups, radiologists and architects, in comparison to one another and a novice control. In doing so, we replicated and extended this prior research: visual expertise is domain specific. However, our eye-tracking data indicate that contrary to this prior work, HVP strategies are transferable across domains. Yet, despite the transfer of HVP strategies, there is neither reduced search time nor greater accuracy in visual search outside of an expert's domain. Therefore, our data suggest that HVP behaviors are a particular form of visual search mechanism that, outside of an expert's native search-ecology, are not necessarily conducive to more general visual search success. It is in addition to explicit knowledge of an expert's domain, how to search, and where to search, that HVP strategies are their most effective for visual search success.

Salient object detection based on global to local visual search guidance

The human eye has the behavior of fixation shift, which is represented by visual search mechanism. Human visual search mechanism has the characteristics of visual guidance from global to local. In order to imitate this behavior, this paper proposes a novel salient object detection model which integrates global and local perception based on visual search guidance. First, by using multi-level feature complementarity, a coarse global perceptual map can be obtained by encoding VGG network and decoding deconvolution network. Then, through the Maximally Stable External Regions (MSER) algorithm, the local hotspot sub-regions in the coarse global perceptual map are intercepted, and generating a visual guidance search path based on the maximum response principle, and the local fine perceptual map is successively merged through the Squeeze-and-Excitation Networks (SENet) step by step. Finally, the salient map integrating the coarse global and fine local perception is achieved. Because only one local area needs to be integrated at a time, which is equivalent to solving a relatively simple problem at a time, it is easy to get more accurate results. The experimental results show that the time-consuming of our model is relatively low and compared with the classical and more recent SOTA methods, our model also shows competitive results.

Enhanced detection of gaze toward an object: Sociocognitive influences on visual search

Another person’s gaze direction is a rich source of social information, especially eyes gazing toward prominent or relevant objects. To guide attention to these important stimuli, visual search mechanisms may incorporate sophisticated coding of eye-gaze and its spatial relationship to other objects. Alternatively, any guidance might reflect the action of simple perceptual ‘templates’ tuned to visual features of socially relevant objects, or intrinsic salience of direct-gazing eyes for human vision. Previous findings that direct gaze (toward oneself) is prioritised over averted gaze do not distinguish between these accounts. To resolve this issue, we compared search for eyes gazing toward a prominent object versus gazing away, finding more efficient search for eyes ‘gazing toward’ the object. This effect was most clearly seen in target-present trials when gaze was task-relevant. Visual search mechanisms appear to specify gazer-object relations, a computational building-block of theory of mind.

孤独症谱系障碍者视觉定向与视觉搜索的特点及神经机制

孤独症谱系障碍者视觉定向与视觉搜索的特点及神经机制

Selective influence and sequential operations: A research strategy for visual search

ABSTRACTWe discuss the problem of elucidating mechanisms of visual search. We begin by considering the history, logic, and methods of relating behavioural or cognitive processes with neural processes. We then survey briefly the cognitive neurophysiology of visual search and essential aspects of the neural circuitry supporting this capacity. We introduce conceptually and empirically a powerful but underutilized experimental approach to dissect the cognitive processes supporting performance of a visual search task with factorial manipulations of singleton-distractor identifiability and stimulus-response cue discriminability. We show that systems factorial technology can distinguish processing architectures from the performance of macaque monkeys. This demonstration offers new opportunities to distinguish neural mechanisms through selective manipulation of visual encoding, search selection, rule encoding, and stimulus-response mapping.

Neural decoding with visual attention using sequential Monte Carlo for leaky integrate-and-fire neurons.

How the brain makes sense of a complicated environment is an important question, and a first step is to be able to reconstruct the stimulus that give rise to an observed brain response. Neural coding relates neurobiological observations to external stimuli using computational methods. Encoding refers to how a stimulus affects the neuronal output, and entails constructing a neural model and parameter estimation. Decoding refers to reconstruction of the stimulus that led to a given neuronal output. Existing decoding methods rarely explain neuronal responses to complicated stimuli in a principled way. Here we perform neural decoding for a mixture of multiple stimuli using the leaky integrate-and-fire model describing neural spike trains, under the visual attention hypothesis of probability mixing in which the neuron only attends to a single stimulus at any given time. We assume either a parallel or serial processing visual search mechanism when decoding multiple simultaneous neurons. We consider one or multiple stochastic stimuli following Ornstein-Uhlenbeck processes, and dynamic neuronal attention that switches following discrete Markov processes. To decode stimuli in such situations, we develop various sequential Monte Carlo particle methods in different settings. The likelihood of the observed spike trains is obtained through the first-passage time probabilities obtained by solving the Fokker-Planck equations. We show that the stochastic stimuli can be successfully decoded by sequential Monte Carlo, and different particle methods perform differently considering the number of observed spike trains, the number of stimuli, model complexity, etc. The proposed novel decoding methods, which analyze the neural data through psychological visual attention theories, provide new perspectives to understand the brain.

Beta and Theta Oscillations Differentially Support Free Versus Forced Control over Multiple-Target Search.

Many important situations require human observers to simultaneously search for more than one object. Despite a long history of research into visual search, the behavioral and neural mechanisms associated with multiple-target search are poorly understood. Here we test the novel theory that the efficiency of looking for multiple targets critically depends on the mode of cognitive control the environment affords to the observer. We used an innovative combination of electroencephalogram (EEG) and eye tracking while participants searched for two targets, within two different contexts: either both targets were present in the search display and observers were free to prioritize either one of them, thus enabling proactive control over selection; or only one of the two targets would be present in each search display, which requires reactive control to reconfigure selection when the wrong target has been prioritized. During proactive control, both univariate and multivariate signals of beta-band (15-35 Hz) power suppression before display onset predicted switches between target selections. This signal originated over midfrontal and sensorimotor regions and has previously been associated with endogenous state changes. In contrast, imposed target selections requiring reactive control elicited prefrontal power enhancements in the delta/theta band (2-8 Hz), but only after display onset. This signal predicted individual differences in associated oculomotor switch costs, reflecting reactive reconfiguration of target selection. The results provide compelling evidence that multiple target representations are differentially prioritized during visual search, and for the first time reveal distinct neural mechanisms underlying proactive and reactive control over multiple-target search.SIGNIFICANCE STATEMENT Searching for more than one object in complex visual scenes can be detrimental for search performance. Although perhaps annoying in daily life, this can have severe consequences in professional settings such as medical and security screening. Previous research has not yet resolved whether multiple-target search involves changing priorities in what people attend to, and how such changes are controlled. We approached these questions by concurrently measuring cortical activity and eye movements using EEG and eye tracking while observers searched for multiple possible targets. Our findings provide the first unequivocal support for the existence of two modes of control during multiple-target search, which are expressed in qualitatively distinct time-frequency signatures of the EEG both before and after visual selection.

Visual Search, Prediction Ability and Brain Neural Mechanisms of Different of Female Volleyball Players

In order to explore whether the experience within the role of movement influences information processing, this paper studies the visual search and prediction abilities of different women volleyball players and their brain neural mechanisms. A laboratory composing of a preparatory room, a master control room, and a test room was established. Subjects were required to perform experimental tasks in the test room alone. The results of multivariate analysis of variance showed that the main effect of the role was significant, indicating that different roles have different responses to different types of attacks. Volleyball players of different roles use different visual search strategies for visual search. The main attack team and the supporting attack team use short search durations more frequently for gaze duration.

Two-dimensional hidden semantic information model for target saliency detection and eyetracking identification

Saliency detection has been applied to the target acquisition case. This paper proposes a two-dimensional hidden Markov model (2D-HMM) that exploits the hidden semantic information of an image to detect its salient regions. A spatial pyramid histogram of oriented gradient descriptors is used to extract features. After encoding the image by a learned dictionary, the 2D-Viterbi algorithm is applied to infer the saliency map. This model can predict fixation of the targets and further creates robust and effective depictions of the targets’ change in posture and viewpoint. To validate the model with a human visual search mechanism, two eyetrack experiments are employed to train our model directly from eye movement data. The results show that our model achieves better performance than visual attention. Moreover, it indicates the plausibility of utilizing visual track data to identify targets.

Visual Search Revived: The Slopes Are Not That Slippery: A Reply to Kristjansson (2015).

Kristjansson (2015) suggests that standard research methods in the study of visual search should be “reconsidered.” He reiterates a useful warning against treating reaction time x set size functions as simple metrics that can be used to label search tasks as “serial” or “parallel.” However, I argue that he goes too far with a broad attack on the use of slopes in the study of visual search. Used wisely, slopes do provide us with insight into the mechanisms of visual search.

Attenuation of visual search deficits through complimentary tactile stimulation in low luminance environments: evidence from ERP and eye tracking analyses.

Event Abstract Back to Event Attenuation of visual search deficits through complimentary tactile stimulation in low luminance environments: evidence from ERP and eye tracking analyses. Mathew Hunter1*, Bettina Olk2 and Ben Godde1 1 Jacobs University, Germany 2 HSD Hochschule Döpfer, University of Applied Sciences, Germany Searching for a visual target among distractors is one of the most common yet complex tasks we are facing in our everyday lives. Despite the fact that our visual search mechanisms are quite adept, we are still subject to limitations of our visual processing which is particularly evident in environments of extremely low luminance (<0.5 cd/m2). Even with a thorough understanding of visual perception in low luminance environments, little is known regarding search processes within these conditions [1], and subsequently, the primary contributing factors to decreases in performance that are observed in these environments and if there are any mechanisms for attenuation. Hunter et al. [2] have provided contrast efficiency functions for simple visual search tasks within the low luminance spectrum, which specifically relate the cumulative effects of relative contrast luminance and the innate contrast of complex target stimuli to search performance. In an attempt to understand the mechanisms behind decreases in performance and how such decreases could be attenuated we have also demonstrated that different aspects of tactile stimulation, such as the predictive probability of a tactile stimulus, or type of tactile stimulation (spatial or frequency information regarding the location of a target), could be used to improve search performance and their fitting along an efficiency function [3]. We suggested a “gating window” providing the psychophysical boundaries pertaining to when in the visual search process tactile information can improve performance, and how this changes with respect to different tactile properties. We observed that coding of a tactile stimulus is only beneficial when a minimum mean response time of 500 ms is required in order to solve the task. The goal of the present study was to assess the neurophysiological mechanisms related to the reception of visual and complimentary tactile information and the visual scanning process. To this end we incorporated measurements of scan patterns (eye tracking) and of event related potentials (ERP). To isolate the temporal determinants of the “gating window”, we specifically focused on the early perceptual components that relate to the visual and tactile reception and integration spanning the first 500 ms of a trial. We targeted seven individual ERP components: P45, N80, P100, N140, N180, N2, and P300 and selected from the Fz, Cz, Pz, C3, C4, P3, P4, O1 and O2 electrodes. Eleven participants performed three different tactile-visual search (target present/absent) paradigms incorporating three different types of tactile encoding, i.e. frequency (20 Hz and 40 Hz stimulation), spatial (left vs right), and frequency and spatial, to provide information regarding the location of a target. We assessed in how far a given type of tactile stimulation was beneficial in improving visual search performance (adapted from [3]). Behavioural results replicated previous findings. The addition of a tactile stimulus designed to provide information about the target, improved performance (RT and d’) which is normally affected in low luminance environments; however, no differences were observed with respect to a specific tactile encoding type. Quantitative analyses of scan patterns measuring the number of saccades, fixation durations, search array dwell time and location were completed. Results revealed that the scan pattern variables were primarily influenced by tactile spatial coding (left vs right) with minimal effects observed in the frequency coding condition. The ERP results primarily implicated the N2 component at Fz, Cz and Pz electrodes as a contributing factor to performance demonstrated by a significant positive correlation with RT (0.87 p < 0.01) and a negative correlation (0.83 p < 0.01) for d’. More specifically, increased peak latencies reflected slower RTs and decreased performance. These correlations remained consistent independent of the type of tactile stimulation. With respect to scanning behavior, the N2 component over the C4 (0.75, p < 0.05) electrode correlated positively with the total number of fixations and negatively with the peak amplitude over the Cz electrode (Cz = -0.67, p < 0.005). The N2 component has been previously implicated in visual tactile cross-modal congruency paradigms [4], where incongruency reflects greater negative potential amplitudes. Consistent with our results, a greater incongruency or conflict would reflect poorer performance (slower RTs and poorer d’ score). Our results provide preliminary evidence with respect to the distinct integration gating component reported by Hunter et al. [3] and ultimately insight into the interactions of multi-sensory integration and performance. The individual components allowed verification of the gating, but more neural processing post this gating process that we did not examine with our study will contribute to response execution.

Parallel mechanisms for visual search in zebrafish.

Parallel visual search mechanisms have been reported previously only in mammals and birds, and not animals lacking an expanded telencephalon such as bees. Here we report the first evidence for parallel visual search in fish using a choice task where the fish had to find a target amongst an increasing number of distractors. Following two-choice discrimination training, zebrafish were presented with the original stimulus within an increasing array of distractor stimuli. We found that zebrafish exhibit no significant change in accuracy and approach latency as the number of distractors increased, providing evidence of parallel processing. This evidence challenges theories of vertebrate neural architecture and the importance of an expanded telencephalon for the evolution of executive function.

Top-Down Saliency Detection via Hidden Semantic Information

Saliency detection has been applied in many cases. This paper proposes a 2D hidden Markov model (2D-HMM) which exploits the hidden semantic information of image to detect the salient regions. A spatial pyramid Histogram of Oriented Gradient (SP-HOG) descriptor is used to extract feature. After encoding the image by a learned dictionary, the 2D-viterbi algorithm is applied to inferring the saliency map. This model can depict the shapes of targets, and also it is robust to the targets’ change of posture and viewpoint. To validate the model with human’s visual search mechanism, eye track experiment is employed to train our model directly from the eye data. The results show that our model achieves a better performance than eye data. Moreover, it indicates that learning from eye track data to figure out their targets is possible.

Autism spectrum disorder, but not amygdala lesions, impairs social attention in visual search

People with autism spectrum disorders (ASD) have pervasive impairments in social interactions, a diagnostic component that may have its roots in atypical social motivation and attention. One of the brain structures implicated in the social abnormalities seen in ASD is the amygdala. To further characterize the impairment of people with ASD in social attention, and to explore the possible role of the amygdala, we employed a series of visual search tasks with both social (faces and people with different postures, emotions, ages, and genders) and non-social stimuli (e.g., electronics, food, and utensils). We first conducted trial-wise analyses of fixation properties and elucidated visual search mechanisms. We found that an attentional mechanism of initial orientation could explain the detection advantage of non-social targets. We then zoomed into fixation-wise analyses. We defined target-relevant effects as the difference in the percentage of fixations that fell on target-congruent vs. target-incongruent items in the array. In Experiment 1, we tested 8 high-functioning adults with ASD, 3 adults with focal bilateral amygdala lesions, and 19 controls. Controls rapidly oriented to target-congruent items and showed a strong and sustained preference for fixating them. Strikingly, people with ASD oriented significantly less and more slowly to target-congruent items, an attentional deficit especially with social targets. By contrast, patients with amygdala lesions performed indistinguishably from controls. In Experiment 2, we recruited a different sample of 13 people with ASD and 8 healthy controls, and tested them on the same search arrays but with all array items equalized for low-level saliency. The results replicated those of Experiment 1. In Experiment 3, we recruited 13 people with ASD, 8 healthy controls, 3 amygdala lesion patients and another group of 11 controls and tested them on a simpler array. Here our group effect for ASD strongly diminished and all four subject groups showed similar target-relevant effects. These findings argue for an attentional deficit in ASD that is disproportionate for social stimuli, cannot be explained by low-level visual properties of the stimuli, and is more severe with high-load top-down task demands. Furthermore, this deficit appears to be independent of the amygdala, and not evident from general social bias independent of the target-directed search.

Monitoring mechanisms in visual search: An fMRI study

This fMRI study investigates the neural underpinning and the cognitive factors associated with monitoring in visual search. A visual search task was designed by pseudo-randomly mixing four experimental conditions, which were obtained through the factorial combination of salience (pop-out vs. non pop-out) and target presence (present vs. absent). The fastest responses were obtained when a salient target was presented, while responses were slowest with target-absent conditions, which required extensive evaluation of the visual scene. Partial Least Square multivariate analysis was used to analyze the fMRI data. The first Latent Variable revealed a set of fronto-parietal and occipital regions, which was cohesively activated especially when the presence of the target stimulus was not easy to discard, such as when all stimuli in the visual scene were non-targets or when one stimulus among the rest was salient (pop-out) but not a target. The most extensive and robust activation within this cohesive set of regions was located in the right inferior/middle frontal gyrus. This finding corroborates evidence in favor of a role of the right lateral prefrontal cortex, and associated regions, for evaluative operations, extending previous findings to the visual search domain.

Search asymmetry and eye movements in infants and adults.

Search asymmetry is characterized by the detection of a feature-present target amidst feature-absent distractors being efficient and unaffected by the number of distractors, whereas detection of a feature-absent target amidst feature-present distractors is typically inefficient and affected by the number of distractors. Although studies have attempted to investigate this phenomenon with infants (e.g., Adler, Inslicht, Rovee-Collier, & Gerhardstein in Infant Behavioral Development, 21, 253-272, 1998; Colombo, Mitchell, Coldren, & Atwater in Journal of Experimental Psychology: Learning, Memory and Cognition, 19, 98-109, 1990), due to methodological limitations, their findings have been unable to definitively establish the development of visual search mechanisms in infants. The present study assessed eye movements as a means to examine an asymmetry in responding to feature-present versus feature-absent targets in 3-month-olds, relative to adults. Saccade latencies to localize a target (or a distractor, as in the homogeneous conditions) were measured as infants and adults randomly viewed feature-present (R among Ps), feature-absent (P among Rs), and homogeneous (either all Rs or all Ps) arrays at set sizes of 1, 3, 5, and 8. Results indicated that neither infants' nor adults' saccade latencies to localize the target in the feature-present arrays were affected by increasing set sizes, suggesting that localization of the target was efficient. In contrast, saccade latencies to localize the target in the feature-absent arrays increased with increasing set sizes for both infants and adults, suggesting an inefficient localization. These findings indicate that infants exhibit an asymmetry consistent with that found with adults, providing support for functional bottom-up selective attention mechanisms in early infancy.

If you don't find it often, you often don't find it: why some cancers are missed in breast cancer screening.

Mammography is an important tool in the early detection of breast cancer. However, the perceptual task is difficult and a significant proportion of cancers are missed. Visual search experiments show that miss (false negative) errors are elevated when targets are rare (low prevalence) but it is unknown if low prevalence is a significant factor under real world, clinical conditions. Here we show that expert mammographers in a real, low-prevalence, clinical setting, miss a much higher percentage of cancers than are missed when the mammographers search for the same cancers under high prevalence conditions. We inserted 50 positive and 50 negative cases into the normal workflow of the breast cancer screening service of an urban hospital over the course of nine months. This rate was slow enough not to markedly raise disease prevalence in the radiologists’ daily practice. Six radiologists subsequently reviewed all 100 cases in a session where the prevalence of disease was 50%. In the clinical setting, participants missed 30% of the cancers. In the high prevalence setting, participants missed just 12% of the same cancers. Under most circumstances, this low prevalence effect is probably adaptive. It is usually wise to be conservative about reporting events with very low base rates (Was that a flying saucer? Probably not.). However, while this response to low prevalence appears to be strongly engrained in human visual search mechanisms, it may not be as adaptive in socially important, low prevalence tasks like medical screening. While the results of any one study must be interpreted cautiously, these data are consistent with the conclusion that this behavioral response to low prevalence could be a substantial contributor to miss errors in breast cancer screening.