scholarly journals The effects of induced optical blur on visual search performance and training

2021 ◽  
pp. 174702182110502
Author(s):  
Azuwan Musa ◽  
Alison R Lane ◽  
Amanda Ellison

Visual search is a task often used in the rehabilitation of patients with cortical and non-cortical visual pathologies such as visual field loss. Reduced visual acuity is often comorbid with these disorders, and it remains poorly defined how low visual acuity may affect a patient’s ability to recover visual function through visual search training. The two experiments reported here investigated whether induced blurring of vision (from 6/15 to 6/60) in a neurotypical population differentially affected various types of feature search tasks, whether there is a minimal acceptable level of visual acuity required for normal search performance, and whether these factors affected the degree to which participants could improve with training. From the results, it can be seen that reducing visual acuity did reduce search speed, but only for tasks where the target was defined by shape or size (not colour), and only when acuity was worse than 6/15. Furthermore, searching behaviour was seen to improve with training in all three feature search tasks, irrespective of the degree of blurring that was induced. The improvement also generalised to a non-trained search task, indicating that an enhanced search strategy had been developed. These findings have important implications for the use of visual search as a rehabilitation aid for partial visual loss, indicating that individuals with even severe comorbid blurring should still be able to benefit from such training.

2018 ◽  
Author(s):  
Alasdair D F Clarke ◽  
Jessica Irons ◽  
Warren James ◽  
Andrew B. Leber ◽  
Amelia R. Hunt

A striking range of individual differences has recently been reported in three different visual search tasks. These differences in performance can be attributed to strategy, that is, the efficiency with which participants control their search to complete the task quickly and accurately. Here we ask if an individual's strategy and performance in one search task is correlated with how they perform in the other two. We tested 64 observers in the three tasks mentioned above over two sessions. Even though the test-retest reliability of the tasks is high, an observer's performance and strategy in one task did not reliably predict their behaviour in the other two. These results suggest search strategies are stable over time, but context-specific. To understand visual search we therefore need to account not only for differences between individuals, but also how individuals interact with the search task and context. These context-specific but stable individual differences in strategy can account for a substantial proportion of variability in search performance.


Author(s):  
Thomas Z. Strybel ◽  
Jan M. Boucher ◽  
Greg E. Fujawa ◽  
Craig S. Volp

The effectiveness of auditory spatial cues in visual search performance was examined in three experiments. Auditory spatial cues are more effective than abrupt visual onsets when the target appears in the peripheral visual field or when the contrast of the target is degraded. The duration of the auditory spatial cue did not affect search performance.


Author(s):  
Gyouhyung Kyung ◽  
Sungryul Park

Objective The aim of this study is to examine the interactive effects of display curvature radius and display size on visual search accuracy, visual search speed, and visual fatigue. Background Although the advantages of curved displays have been reported, little is known about the interactive effects of display curvature radius and size. Method Twenty-seven individuals performed visual search tasks at a viewing distance of 50 cm using eight configurations involving four display curvature radii (400R, 600R, 1200R, and flat) and two display sizes (33″ and 50″). To simulate curved screens, five flat display panels were horizontally arranged with their centers concentrically repositioned following each display curvature radius. Results For accuracy, speed, and fatigue, 33″–600R and 50″–600R provided the best or comparable-to-best results, whereas 50″–flat provided the worst results. For accuracy and fatigue, 33″–flat was the second worst. The changes in the horizontal field of view and viewing angle due to display curvature as well as the association between effective display curvature radii and empirical horopter (loci of perceived equidistance) can explain these results. Conclusion The interactive effects of display curvature radius and size were evident for visual search performance and fatigue. Beneficial effects of curved displays were maintained across 33″ and 50″, whereas increasing flat display size from 33″ to 50″ was detrimental. Application For visual search tasks at a viewing distance of 50 cm, 33″–600R and 50″ 600R displays are recommended, as opposed to 33″ and 50″ flat displays. Wide flat displays must be carefully considered for visual display terminal tasks.


Vision ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 46
Author(s):  
Alasdair D. F. Clarke ◽  
Anna Nowakowska ◽  
Amelia R. Hunt

Visual search is a popular tool for studying a range of questions about perception and attention, thanks to the ease with which the basic paradigm can be controlled and manipulated. While often thought of as a sub-field of vision science, search tasks are significantly more complex than most other perceptual tasks, with strategy and decision playing an essential, but neglected, role. In this review, we briefly describe some of the important theoretical advances about perception and attention that have been gained from studying visual search within the signal detection and guided search frameworks. Under most circumstances, search also involves executing a series of eye movements. We argue that understanding the contribution of biases, routines and strategies to visual search performance over multiple fixations will lead to new insights about these decision-related processes and how they interact with perception and attention. We also highlight the neglected potential for variability, both within and between searchers, to contribute to our understanding of visual search. The exciting challenge will be to account for variations in search performance caused by these numerous factors and their interactions. We conclude the review with some recommendations for ways future research can tackle these challenges to move the field forward.


Author(s):  
Mary P. Czerwinski ◽  
Evan M. Feldman ◽  
Edward Cutrell

Traditional studies of attention, training and visual search have focused on the use of separable dimensions (usually alphanumeric stimuli), and equating the number of items in consistent versus varied mapping training paradigms. However, the design of visual displays requires a heavy reliance upon configural and integral dimensions (stimuli that group). This set of studies examines the effects of configural dimensions (also using alphanumeric stimuli), as well as equating the number of training trials on specific targets between consistent versus varied mapping conditions. Predictions from extant theories of attention and visual search will be discussed where relevant. Results show that both factors have a large influence on the effects of training in visual search tasks. The influence of these variables needs to be incorporated into current theories of attention and visual search, especially as they are applied to the design of graphical user interfaces and visual displays.


2003 ◽  
Vol 89 (6) ◽  
pp. 3340-3343 ◽  
Author(s):  
Neil G. Muggleton ◽  
Chi-Hung Juan ◽  
Alan Cowey ◽  
Vincent Walsh

Recent physiological recording studies in monkeys have suggested that the frontal eye fields (FEFs) are involved in visual scene analysis even when eye movement commands are not required. We examined this proposed function of the human frontal eye fields during performance of visual search tasks in which difficulty was matched and eye movements were neither necessary nor required. Magnetic stimulation over FEF modulated performance on a conjunction search task and a simple feature search task in which the target was unpredictable from trial to trial, primarily by increasing false alarm responses. Simple feature search with a predictable target was not affected. The results establish that human FEFs are critical to visual selection, regardless of the need to generate a saccade command.


2013 ◽  
Vol 6 (4) ◽  
Author(s):  
Brent Winslow ◽  
Angela Carpenter ◽  
Jesse Flint ◽  
Xuezhong Wang ◽  
David Tomasetti ◽  
...  

Visual search is a complex task that involves many neural pathways to identify relevant areas of interest within a scene. Humans remain a critical component in visual search tasks, as they can effectively perceive anomalies within complex scenes. However, this task can be challenging, particularly under time pressure. In order to improve visual search training and performance, an objective, process-based measure is needed. Eye tracking technology can be used to drive real-time parsing of EEG recordings, providing an indication of the analysis process. In the current study, eye fixations were used to generate ERPs during a visual search task. Clear differences were observed following performance, suggesting that neurophysiological signatures could be developed to prevent errors in visual search tasks.


2021 ◽  
Author(s):  
Wen Wen ◽  
Zhibang Huang ◽  
Yin Hou ◽  
Sheng Li

To perform challenging visual search tasks, attention should be selectively allocated to promote targets and inhibit distractors. Rejection templates based on the distractor's feature can be built to constrain the search process by filtering-out matched stimuli. We measured electroencephalography (EEG) of human participants when they performed a visual search task under conditions in which the distractor cues were constant within a block (fixed-cueing) or changed on a trial-by-trial basis (varied-cueing). Sustained representation of the cued colors could be decoded from the whole-brain EEG signal during the retention interval in the fixed-cueing condition, implying a formed rejection template. By contrast, transient representation of the cued colors was observed in the varied-cueing condition only after cue onset with significant but lower decoding accuracy than the fixed-cueing condition. The differential neural representations of the to-be-ignored color in the two cueing conditions agreed with the visual search performance that the fixed-cueing condition demonstrated a larger inhibition benefit of the distractor cueing than the varied-cueing condition. During the retention interval, we also observed stronger posterior alpha lateralization and mid-frontal theta/beta power in the varied-cueing condition, indicating the cognitive costs in template formation caused by the trialwisely change of distractor colors. The stable template formed in the fixed-cueing condition was utilized to inhibit the matched distractors in the search array and this was accompanied by larger mid-frontal theta activity. Taken together, our findings highlighted the critical roles of distractor consistency in linking template formation to successful distractor inhibition and the functional relevance of frontal theta activity in support of template formation and implementation.


1981 ◽  
Vol 53 (2) ◽  
pp. 411-418
Author(s):  
Lance A. Portnoff ◽  
Jerome A. Yesavage ◽  
Mary B. Acker

Disturbances in attention are among the most frequent cognitive abnormalities in schizophrenia. Recent research has suggested that some schizophrenics have difficulty with visual tracking, which is suggestive of attentional deficits. To investigate differential visual-search performance by schizophrenics, 15 chronic undifferentiated and 15 paranoid schizophrenics were compared with 15 normals on two tests measuring visual search in a systematic and an unsystematic stimulus mode. Chronic schizophrenics showed difficulty with both kinds of visual-search tasks. In contrast, paranoids had only a deficit in the systematic visual-search task. Their ability for visual search in an unsystematized stimulus array was equivalent to that of normals. Although replication and cross-validation is needed to confirm these findings, it appears that the two tests of visual search may provide a useful ancillary method for differential diagnosis between these two types of schizophrenia.


2021 ◽  
Vol 11 (3) ◽  
pp. 283
Author(s):  
Olga Lukashova-Sanz ◽  
Siegfried Wahl

Visual search becomes challenging when the time to find the target is limited. Here we focus on how performance in visual search can be improved via a subtle saliency-aware modulation of the scene. Specifically, we investigate whether blurring salient regions of the scene can improve participant’s ability to find the target faster when the target is located in non-salient areas. A set of real-world omnidirectional images were displayed in virtual reality with a search target overlaid on the visual scene at a pseudorandom location. Participants performed a visual search task in three conditions defined by blur strength, where the task was to find the target as fast as possible. The mean search time, and the proportion of trials where participants failed to find the target, were compared across different conditions. Furthermore, the number and duration of fixations were evaluated. A significant effect of blur on behavioral and fixation metrics was found using linear mixed models. This study shows that it is possible to improve the performance by a saliency-aware subtle scene modulation in a challenging realistic visual search scenario. The current work provides an insight into potential visual augmentation designs aiming to improve user’s performance in everyday visual search tasks.


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