Visual Conjunction Search Research Articles

A novel gaze-based visual search task for children with CVI: A twin study

Visual search is often impaired in children with cerebral visual impairment (CVI), but the current assessment of visual search performance is limited. This study aimed to investigate underlying visual search processes in detail by including gaze-based measurements. Twin brothers (age 11.8 years), one diagnosed with CVI and one with neurotypical development, underwent a newly developed conjunction visual search task while simultaneously their gaze was recorded. In addition to speed and accuracy, we analyzed additional timing and spatial parameters of the search process before and after their initial fixation in the target area. The twin with CVI had good visual sensory functions, but impaired search performance indicated by longer search time and larger search areas. Also, it was observed that in more difficult task conditions, he tended to miss the target, even when fixating on it. These results point towards higher-order visual deficits. This study gives insight into the visual search challenges of a child with CVI. Mapping the search process in detail provided new and distinctive information that can shape more tailored support. Coupling verbal and nonverbal gaze-based outcomes is a promising first step towards a more inclusive nonverbal and nonmotor assessment.

Reading problems and their connection with visual search and attention.

Attention has been hypothesized to act as a sequential gating mechanism for the orderly processing of letters and words. These same visuoattentional processes are often assumed to partake in some but not all types of visual search. In the current study, 24 dyslexic and 36 typical readers completed an attentionally demanding visual conjunction search. Visual feature search served as an internal control. It has been suggested that reading problems should go hand in hand with specific problems in visual conjunction search-particularly elevated conjunction search slopes (time per search item)-often interpreted as a problem with visual attention. Results showed that reading problems were associated with slower visual search, especially conjunction search. However, reading deficits were not associated with increased conjunction search slopes but instead with increased search intercepts, traditionally not interpreted as reflecting attention. We discuss these results in the context of hypothesized visuoattentional problems in dyslexia. Remaining open to multiple interpretations of the data, the current study demonstrates that difficulties in visual search are associated with reading problems, in accordance with growing literature on visual cognition problems in developmental dyslexia.

Visual search in infantile nystagmus syndrome

ABSTRACT Clinical relevance Research on infantile nystagmus syndrome (INS) and visual search is limited. Conducting this research could assist practitioners in understanding how INS affects the real-life visual activities of patients and aid in developing new clinical visual function assessments for INS. Background The aim of this work is to investigate how subjects with INS perform visual search tasks, and, particularly, to assess how INS subjects perform when targets are located at their null position or away from it, and when under additional cognitive demands. Methods INS subjects (N = 15) and controls (N = 20) performed conjunction and feature search tasks, both with and without mental arithmetic. Search performance was assessed using log-transformed total search time, gaze-dependent search time, and accuracy. Cognitive demand was quantified by pupil size and the NASA task-load index score. Results INS subjects showed longer search times compared to controls in conjunction search (P < 0.01), but not in feature search. Within INS and control subjects, the total search times were significantly increased by the addition of mental arithmetic (P < 0.0001). There was no difference in gaze-dependent search times between null target position and 15° away from null target position of subjects in conjunction search (P > 0.05). Accuracies were 100% for both control and INS subjects in both conjunction and feature search. Conclusion Conjunction visual search was impaired in adult INS subjects, and further worsened under increased cognitive demand. The null position did not affect the visual search performance in INS

Visual and cognitive processes contribute to age-related improvements in visual selective attention.

Children (N = 103, 4-9 years, 59 females, 84% White, c. 2019) completed visual processing, visual feature integration (color, luminance, motion), and visual search tasks. Contrast sensitivity and feature search improved with age similarly for luminance and color-defined targets. Incidental feature integration improved more with age for color-motion than luminance-motion. Individual differences in feature search ( = .11) and incidental feature integration ( = .06) mediated age-related changes in conjunction visual search, an index of visual selective attention. These findings suggest that visual selective attention is best conceptualized as a series of developmental trajectories, within an individual, that vary by an object's defining features. These data have implications for design of educational and interventional strategies intended to maximize attention for learning and memory.

A feature and conjunction visual search immersive virtual reality serious game for measuring spatial and distractor inhibition attention using response time and action kinematics

ABSTRACT Background Treisman (1980) proposed that visual-spatial attention to targets presented with distractors involves parallel and serial cognition. When the target is different from distractors by a single feature, the number of distractors does not influence search speed (parallel). However, when the target is different from the distractor by a conjunction of features, increased numbers of distractors increase task difficulty (serial). Here, we developed a serious game in immersive virtual reality (IVR) for evaluating spatial and distractor inhibition attention. Methods We tested 60 healthy participants. They performed the serious game in which they had to find a target mole wearing a red miner’s helmet. In the single feature parallel conditions, the distractor moles wore blue (miner’s or horned) helmets, and in the conjunction feature serial conditions, the distractor moles wore blue miner’s helmets or red horned helmets. There were 11–17–23 distractors. Responses were made with the dominant hand by hitting the target with a virtual hammer. We measured mean response time (RT), mean velocity (MV) and coefficient of variance of speed (CV). Results Participants were significantly slower (RT and MV) and showed greater CV when responding to targets in conjunction compared to single feature search tasks. Further, participants were slower (RT and MV) and showed greater CV when the number of distractors increased. A significant interaction between search tasks and distractors showed that RT and CV only increased with distractor number for the conjunction search tasks. MV decreased with distractor number for both single and conjunction tasks, with a stronger decrease for conjunction relative to single feature search. Conclusion The results replicated previous findings, providing support for the use of immersive virtual reality technology for the simultaneous evaluation of spatial and distractor inhibition attention using complex 3D objects.

Attentional disengagement effect based on relevant features.

In visual search tasks, distractors similar to the target can attract our attention and affect the speed of attentional disengagement. The attentional disengagement refers to shifting attention away from stimuli that are not relevant to the task. Previous studies mainly focused on the attentional disengagement of one feature dimension. However, the mechanisms of different feature dimensions on attentional disengagement in single and conjunction visual search remain unclear. In the current study, we adopted the oculomotor disengagement paradigm and used saccade latency as an indicator to explore the effects of different feature dimensions of center stimuli on attentional disengagement. In both single and conjunction feature search tasks, participants began each search by fixating on a center stimulus that appeared simultaneously with search display but would not be the target. Participants were instructed to ensure the first saccade to the target location. In Experiments 1A (single feature search) and 1B (conjunction feature search), we found that the attentional disengagement was significantly delayed or accelerated when center stimuli shared color features with the target or salient distractor, but not in shape feature. Moreover, we found that the difference between the two feature dimensions might be caused by their different search difficulty (Experiment 1C). Therefore, in Experiment 2, we matched the difficulty of searching for color and shape tasks before exploring whether there were differences in the effects of different feature dimensions on attentional disengagement. However, the results in Experiment 2 were similar to those in Experiment 1A, indicating that the different effects of feature dimensions on attentional disengagement were caused by feature asymmetry. Therefore, in Experiment 3, we improved the salient discernibility of shape dimension and matched color search to it. The results showed that although the attentional disengagement was delayed in shape dimension, it was still smaller than that in color dimension. Our results supported that goal-oriented attention sets were the main cause of delayed attentional disengagement. By series of experiments, we found that the utilization of different feature dimensions was associated with task difficulty and the features asymmetry in both single and conjunction visual search.

Visual search training benefits from the integrative effect of enhanced covert attention and optimized overt eye movements.

Training serves as an effective approach to improve visual search performance when the target does not automatically pop out from the distractors. In the present study, we trained participants on a conjunction visual search task and examined the training effects in behavior and eye movement. The results of Experiments 1 to 4 showed that training improved behavioral performance and reduced the number of saccades and overall scanning time. Training also increased the search initiation time before the first saccade and the proportion of trials in which the participants correctly identified the target without any saccade, but these effects were modulated by stimulus’ parameters. In Experiment 5, we simultaneously recorded eye movements and electroencephalography signals and the results revealed significant N2 posterior contralateral (N2pc) components after the stimulus onset (i.e., stimulus-locked) and before the first saccade (i.e., saccade-locked) when the search target was the trained one. These N2pc components can be considered as the neural signatures for the enhanced covert attention to the trained target. Together with the training-induced increase in functional visual field, these mechanisms could support the beneficial effects of increased search initiation time and reduced number of saccades. These findings suggest that visual search training enhanced covert attention to target and optimized overt eye movements to facilitate search performance.

Digital haptics improve speed of visual search performance in a dual-task setting

Dashboard-mounted touchscreen tablets are now common in vehicles. Screen/phone use in cars likely shifts drivers’ attention away from the road and contributes to risk of accidents. Nevertheless, vision is subject to multisensory influences from other senses. Haptics may help maintain or even increase visual attention to the road, while still allowing for reliable dashboard control. Here, we provide a proof-of-concept for the effectiveness of digital haptic technologies (hereafter digital haptics), which use ultrasonic vibrations on a tablet screen to render haptic perceptions. Healthy human participants (N = 25) completed a divided-attention paradigm. The primary task was a centrally-presented visual conjunction search task, and the secondary task entailed control of laterally-presented sliders on the tablet. Sliders were presented visually, haptically, or visuo-haptically and were vertical, horizontal or circular. We reasoned that the primary task would be performed best when the secondary task was haptic-only. Reaction times (RTs) on the visual search task were fastest when the tablet task was haptic-only. This was not due to a speed-accuracy trade-off; there was no evidence for modulation of VST accuracy according to modality of the tablet task. These results provide the first quantitative support for introducing digital haptics into vehicle and similar contexts.

The perception of subset quantity and items in an environment with distractors in a population with mathematical learning difficulties

People often perceive a quantity of specific objects that appear as part of an overall group of items (a subset). This study investigates this type of perception among a population with mathematical leaning difficulties (MLD). Sixty-two participants (mean age: 26.82) reported the general and subset quantity of items using a subset quantity detection task or a conjunction visual search task. MLD had difficulties perceiving both the general quantity presented and the subset quantity of items. They also had difficulties preforming a conjunction visual search task, even when the task did not involve numerical processing. MLD has spatial difficulties in the form of visual search and subset quantity detection. The current study suggests that MLD might experience greater difficulties in daily tasks, which might be related to those tasks (e.g., detecting the amount of forks among other items of silverware on the table).

Work fatigue and attention performance in remise and taxi drivers

Fatigue is considered a risk factor in traffic accidents, particularly in the case of professional drivers. In this population, extended working hours constitute one of the main precursors of fatigue. The objective of this work was to study the subjective perception of fatigue and the attentional performance in taxi / remise drivers at the beginning and end of a work day. Professional drivers (n = 30) were compared with a group of workers from different sectors (n = 30), matched by gender and age. A Fatigue severity scale, an Analogue visual fatigue scale, and a Conjunctive visual search task were administered. Overall, professional drivers showed higher scores in the fatigue severity scale. With regard to the attentional task, the ANOVA showed that professional drivers were less accurate in their performance. The practical implications of these findings are discussed.

The efficiency of visual search for a frequently changed target is preserved in older adults.

Visual search is a psychological function integral to most people's daily lives. The extent to which visual search efficiency, and in particular the ability to use top-down attention in visual search, changes across the lifespan has been the focus of ongoing research. Here we sought to understand how the ability to frequently and dynamically change the target in a conjunction search task was affected by ageing. To do this, we compared visual search performance of a group of younger and older adults under conditions in which the target type was determined by a cue and could change on trial-to-trial basis (Intermixed), versus when the target type was fixed for a block of trials (Blocked). Although older adults were overall slower at the conjunction visual search task, and both groups were slower in the Intermixed compared with the Blocked Condition, older adults were not disproportionately affected by the Intermixed relative to the Blocked conditions. These results indicate that the ability to frequently change the target of visual search is preserved in older adults. This conclusion is consistent with an emerging consensus that many aspects of visual search and top-down contributions to it are preserved across the lifespan. It is also consistent with a growing body of work which challenges the neurocognitive theories of ageing that predict sweeping deficits in complex top-down components of cognition.

Action Video Games Enhance Attentional Control and Phonological Decoding in Children with Developmental Dyslexia.

Reading acquisition is extremely difficult for about 5% of children because they are affected by a heritable neurobiological disorder called developmental dyslexia (DD). Intervention studies can be used to investigate the causal role of neurocognitive deficits in DD. Recently, it has been proposed that action video games (AVGs)—enhancing attentional control—could improve perception and working memory as well as reading skills. In a partial crossover intervention study, we investigated the effect of AVG and non-AVG training on attentional control using a conjunction visual search task in children with DD. We also measured the non-alphanumeric rapid automatized naming (RAN), phonological decoding and word reading before and after AVG and non-AVG training. After both video game training sessions no effect was found in non-alphanumeric RAN and in word reading performance. However, after only 12 h of AVG training the attentional control was improved (i.e., the set-size slopes were flatter in visual search) and phonological decoding speed was accelerated. Crucially, attentional control and phonological decoding speed were increased only in DD children whose video game score was highly efficient after the AVG training. We demonstrated that only an efficient AVG training induces a plasticity of the fronto-parietal attentional control linked to a selective phonological decoding improvement in children with DD.

Spatial attention and spatial short term memory in PSP and Parkinson's disease

Progressive Supranuclear Palsy (PSP) is a neurodegenerative disorder characterised by deterioration in motor, oculomotor and cognitive function. A key clinical feature of PSP is the progressive paralysis of eye movements, most notably for vertical saccades. These oculomotor signs can be subtle, however, and PSP is often misdiagnosed as Parkinson’s disease (PD), in its early stages. Although some of the clinical features of PD and PSP overlap, they are distinct disorders with differing underlying pathological processes, responses to treatment and prognoses. One key difference lies in the effects the diseases have on cognition. The oculomotor system is tightly linked to cognitive processes such as spatial attention and spatial short-term memory (sSTM), and previous studies have suggested that PSP and PD experience different deficits in these domains. We therefore hypothesised that people with PSP (N = 15) would experience problems with attention (assessed with feature and conjunction visual search tasks) and sSTM (assessed with the Corsi blocks task) compared to people with PD (N = 16) and Age Matched Controls (N = 15). As predicted, feature and conjunction search were sgnificantly slower in the PSP group compared to the other groups, and this deficit was significantly worse for feature compared to conjunction search. The PD group did not differ from AMC on feature search but were significantly impaired on the conjunction search. The PSP group also had a pronounced vertical sSTM impairment that was not present in PD or AMC groups. It is argued that PSP is associated with specific impairment of visuospatial cognition which is caused by degeneration of the oculomotor structures that support exogenous spatial attention, consistent with oculomotor theories of spatial attention and memory.

Analysis of omission and commission errors in a visual search task by school-age children (Análisis de errores de omisión y comisión en una tarea de búsqueda visual en niños de edad escolar)

ABSTRACT Visual search is an attentional process that requires the subject to search for a target among distractors. Failures in this process are associated with a variety of difficulties that manifest in different stages of development. They are often assessed using Conjunction Visual Search tasks. Despite this, few studies have analysed the errors committed in these tasks during development in detail. The purpose of this study is to analyse the types of errors associated with developmental changes in school-age children. Our hypotheses are that younger children would present more errors than older ones; there would be more omission errors than commission errors; younger children would commit more omission errors than older ones; and omission errors would increase as the number of distractors increased. The study results have shown that errors tend to decrease throughout development. Specifically, commission errors remain stable according to the number of distractors and task complexity, while omission errors increase according to these variables. These results provide evidence indicating that error types are based on different cognitive processes.

Where's the wine? Heavy social drinkers show attentional bias towards alcohol in a visual conjunction search task.

Research indicates that high consumers of alcohol exhibit attentional bias (AB) towards alcohol-related cues, suggestive of a cognitive mechanism that might drive substance seeking. Many tasks that measure AB (e.g. visual probe, addiction Stroop), however, are limited by their reliance on non-appetitive control cues, the serial presentation of stimuli and their poor internal reliability. The current study employed a visual conjunction search (VCS) task capable of presenting multiple alcoholic and non-alcoholic appetitive cues simultaneously to assess whether social drinkers attend selectively to alcoholic stimuli. To assess the construct validity of this task, we examined whether alcohol consumption and related problems, subjective craving and drinking motives predict alcohol-specific AB. A VCS task was performed in a laboratory setting, which required participants to detect the presence of appetitive alcoholic (wine, beer) and non-alcoholic (cola, lemonade) targets within arrays of matching and non-matching distractors. Data from 99 participants were assessed [meanage =20.77, standard deviation (SD)=2.98; 64 (65%) females], with 81.8% meeting the threshold for harmful alcohol consumption (meanAUDIT =12.89, SD=5.79). Self-reports of alcohol consumption and related problems [Alcohol Use Disorders Identification Test (AUDIT)], subjective craving (Alcohol Craving Questionnaire Short Form) and drinking motives (Drinking Motives Questionnaire Short Form) were obtained, and the VCS task measured response times for the correct detection of alcoholic and non-alcoholic targets. Participants were significantly quicker to detect alcoholic relative to non-alcoholic appetitive targets (P<0.001, dz =0.41), which was predicted positively by AUDIT scores (P=0.013, R2 =0.06%). The VCS task achieved excellent reliability (α>0.79), superior to other paradigms. The visual conjunction search task appears to be a highly reliable method for assessing alcohol-related attentional bias, and shows that heavy social drinkers prioritize alcoholic cues in their immediate environment.

Foraging with Anne Treisman: Features versus conjunctions, patch leaving and memory for foraged locations.

Foraging tasks are increasingly used to investigate human visual attention as they may provide a more dynamic and multifaceted picture of attentional orienting than more traditionally used visual search tasks. A common way of assessing foraging performance involves measuring when foragers decide to move to a new "patch" with a higher yield. We assessed this using Anne Treisman's famous feature versus conjunction manipulation in an iPad foraging task. We measured how well patch leaving accorded with the predictions of the marginal value theorem that describes how foragers may optimize their foraging by leaving a patch once the average yield within a patch drops below the average yield in the whole environment. Human foraging in our paradigm deviated from the predictions of such optimal foraging conceptions, and our participants kept on foraging within the same patch for longer than expected. Patch leaving and intertarget times differed surprisingly little between feature and conjunction foraging, especially in light of the dramatic differences typically seen between performance on feature and conjunction visual search tasks. Other aspects of foraging performance (run number and switch costs) differed strongly between feature and conjunction foraging, however. We conclude that human foraging is probably influenced by too many factors to be captured with a relatively simple mathematical model.

Cognitive flexibility in adulthood and advanced age: Evidence of internal and external validity

Aging causes changes that affect functioning of cognitive processes such as cognitive flexibility (CF). Given it allows changing both behavior and thinking in dynamic contexts, it constitutes an essential trait of adaptive, goal-oriented behavior. Despite its importance, specific techniques to evaluate CF in older adults are lacking. The goal of this article is to describe and comparatively analyze the functioning of CF in a sample of 169 individuals representing three age groups—younger-age, middle-age and advanced-age adults—by obtaining evidence of internal and external validity. Using a correlational and cross-sectional research design, four studies were conducted in order to evaluate construct validity—fulfillment of experimental paradigm criteria and contrast between groups and tests with different methods. In addition to the Fingers Task, the study used the CAMBIOS Cognitive Flexibility Test, TAC’s Conjunction Visual Search Task (which evaluates perceptual inhibition) and a verbal fluency task with changes. The results provide evidence of the functioning of CF in adulthood and advanced age, which has implications for neurocognitive clinical evaluation in these stages of life. Additionally, evidence was obtained in favor of the concurrent validity of the instruments used to measure CF, contributing to the solidity of future studies on this executive function.

Grouping does not help you to guide conjunction visual search

Grouping does not help you to guide conjunction visual search

Bilingual Advantages in Inhibition or Selective Attention: More Challenges.

A large sample (N = 141) of college students participated in both a conjunctive visual search task and an ambiguous figures task that have been used as tests of selective attention. Tests for effects of bilingualism on attentional control were conducted by both partitioning the participants into bilinguals and monolinguals and by treating bilingualism as a continuous variable, but there were no effects of bilingualism in any of the tests. Bayes factor analyses confirmed that the evidence substantially favored the null hypothesis. These new findings mesh with failures to replicate language-group differences in congruency-sequence effects, inhibition-of-return, and working memory capacity. The evidence that bilinguals are better than monolinguals at attentional control is equivocal at best.

Visual attention, biological motion perception, and healthy ageing

Biological motion perception is the ability of the visual system to perceive complex human movement patterns. The previous studies have shown a direct link between attentional abilities and performance on biological motion tasks, both of which have been shown to deteriorate with age. However, it is not known whether there is a direct link between age-related deficits in biological motion processing and attention. Here, we investigated whether age-related changes in biological motion perception are mediated by impaired attentional abilities. To assess basic biological motion performance, we asked 42 younger (M = 21 years) and 39 older adults (M = 69 years) to indicate the facing direction of point-light actions. Performance did not differ between age groups. We assessed visual spatial and selective attentional abilities, using a range of tasks: conjunctive visual search, spatial cueing, and the Stroop task. Across all tasks, older adults were significantly slower to respond and exhibited larger interference/cueing effects, compared to younger adults. To assess attentional demands in relation with biological motion perception, participants performed a biological motion search task for which they had to indicate the presence of a target point-light walker among a varied number of distracters. Older adults were slower, and generally worse than younger adults at discriminating the walkers. Correlations showed that there was no significant relationship between performance in attention tasks and biological motion processing, which indicates that age-related changes in biological motion perception are unlikely to be driven by general attentional decline.