scholarly journals Principles of tactile search over the body

2019 ◽  
Author(s):  
Elizabeth J. Halfen ◽  
John F. Magnotti ◽  
Md. Shoaibur Rahman ◽  
Jeffrey M. Yau

AbstractAlthough we experience complex patterns over our entire body, how we selectively perceive multi-site touch over our bodies remains poorly understood. Here, we characterized tactile search behavior over the body using a tactile analog of the classic visual search task. Participants judged whether a target stimulus (e.g., 10-Hz vibration) was present or absent on the upper or lower limbs. When present, the target stimulus could occur alone or with distractor stimuli (e.g., 30-Hz vibrations) on other body locations. We varied the number and spatial configurations of the distractors as well as the target and distractor frequencies and measured the impact of these factors on search response times. First, we found that response times were faster on target-present trials compared to target-absent trials. Second, response times increased with the number of stimulated sites, suggesting a serial search process. Third, search performance differed depending on stimulus frequencies. This frequency-dependent behavior may be related to perceptual grouping effects based on timing cues. We constructed models to explore how the locations of the tactile cues influenced search behavior. Our modeling results reveal that, in isolation, cues on the index fingers make relatively greater contributions to search performance compared to stimulation experienced on other body sites. Additionally, co-stimulation of sites within the same limb or simply on the same body side preferentially influence search behavior. Our collective findings identify some principles of attentional search that are common to vision and touch, but others that highlight key differences that may be unique to body-based spatial perception.New & NoteworthyLittle is known about how we selectively experience multi-site touch over the body. Using a tactile analog of the classic visual search paradigm, we show that tactile search behavior for flutter cues is generally consistent with a serial search process. Modeling results reveal the preferential contributions of index finger stimulation and two-site interactions involving ipsilateral and within-limb patterns. Our results offer initial evidence for spatial and temporal principles underlying tactile search behavior over the body.

2020 ◽  
Vol 123 (5) ◽  
pp. 1955-1968
Author(s):  
Elizabeth J. Halfen ◽  
John F. Magnotti ◽  
Md. Shoaibur Rahman ◽  
Jeffrey M. Yau

Little is known about how we selectively experience multisite touch patterns over the body. Using a tactile analog of the classic visual target search paradigm, we show that tactile search behavior for flutter cues is generally consistent with a serial search process. Modeling results reveal the preferential contributions of index finger stimulation and two-site stimulus interactions involving ipsilateral patterns and within-limb patterns. Our results offer initial evidence for spatial and temporal principles underlying tactile search behavior over the body.


Author(s):  
Tobias Rieger ◽  
Lydia Heilmann ◽  
Dietrich Manzey

AbstractVisual inspection of luggage using X-ray technology at airports is a time-sensitive task that is often supported by automated systems to increase performance and reduce workload. The present study evaluated how time pressure and automation support influence visual search behavior and performance in a simulated luggage screening task. Moreover, we also investigated how target expectancy (i.e., targets appearing in a target-often location or not) influenced performance and visual search behavior. We used a paradigm where participants used the mouse to uncover a portion of the screen which allowed us to track how much of the stimulus participants uncovered prior to their decision. Participants were randomly assigned to either a high (5-s time per trial) or a low (10-s time per trial) time-pressure condition. In half of the trials, participants were supported by an automated diagnostic aid (85% reliability) in deciding whether a threat item was present. Moreover, within each half, in target-present trials, targets appeared in a predictable location (i.e., 70% of targets appeared in the same quadrant of the image) to investigate effects of target expectancy. The results revealed better detection performance with low time pressure and faster response times with high time pressure. There was an overall negative effect of automation support because the automation was only moderately reliable. Participants also uncovered a smaller amount of the stimulus under high time pressure in target-absent trials. Target expectancy of target location improved accuracy, speed, and the amount of uncovered space needed for the search.Significance Statement Luggage screening is a safety–critical real-world visual search task which often has to be done under time pressure. The present research found that time pressure compromises performance and increases the risk to miss critical items even with automation support. Moreover, even highly reliable automated support may not improve performance if it does not exceed the manual capabilities of the human screener. Lastly, the present research also showed that heuristic search strategies (e.g., areas where targets appear more often) seem to guide attention also in luggage screening.


Author(s):  
P. Manivannan ◽  
Sara Czaja ◽  
Colin Drury ◽  
Chi Ming Ip

Visual search is an important component of many real world tasks such as industrial inspection and driving. Several studies have shown that age has an impact on visual search performance. In general older people demonstrate poorer performance on such tasks as compared to younger people. However, there is controversy regarding the source of the age-performance effect. The objective of this study was to examine the relationship between component abilities and visual search performance, in order to identify the locus of age-related performance differences. Six abilities including reaction time, working memory, selective attention and spatial localization were identified as important components of visual search performance. Thirty-two subjects ranging in age from 18 - 84 years, categorized in three different age groups (young, middle, and older) participated in the study. Their component abilities were measured and they performed a visual search task. The visual search task varied in complexity in terms of type of targets detected. Significant relationships were found between some of the component skills and search performance. Significant age effects were also observed. A model was developed using hierarchical multiple linear regression to explain the variance in search performance. Results indicated that reaction time, selective attention, and age were important predictors of search performance with reaction time and selective attention accounting for most of the variance.


Author(s):  
May Jorella Lazaro ◽  
Sungho Kim ◽  
Yohan Kang ◽  
Myung Hwan Yun

Clutter in tactical situation displays (TSD) is a persistent problem that affects pilots’ performance. Decluttering methods such as dimming, dotting, small-sizing and removal have been used in several display types to reduce clutter. This study aims to investigate the effects of different decluttering methods applied in TSD on pilots’ visual search performance. It also aims to uncover the basic psychophysical processes underlying the pilots’ visual search behavior through computational modeling. Data from fifteen Air-Force pilots showed that accuracy is higher and response time is faster when the TSD is decluttered, regardless of the technique. However, when the data was fitted into the hierarchical drift-diffusion model, it was revealed that among the techniques tested, dimming yielded the best search performance based on the model parameters. This study suggests that analyzing behavioral data through computational modeling may lead to better insights that are more practical and applicable in solving the issues in visual search in TSDs.


Author(s):  
Karl F. Van Orden ◽  
Joseph DiVita

Previous research has demonstrated that search times are reduced when flicker is used to highlight color coded symbols, but that flicker is not distracting when subjects must search for non-highlighted symbols. This prompted an examination of flicker and other stimulus dimensions in a conjunctive search paradigm. In all experiments, at least 15 subjects completed a minimum of 330 trials in which they indicated the presence or absence of target stimuli on a CRT display that contained either 8, 16 or 32 items. In Experiment 1, subjects searched for blue-steady or red-flickering (5.6 Hz) circular targets among blue-flickering and red-steady distractors. Blue-steady targets produced a more efficient search rate (11.6 msec/item) than red-flickering targets (19.3 msec/item). In Experiment 2, a conjunction of flicker and size (large and small filled circles) yielded the opposite results; the search performance for large-flickering targets was unequivocally parallel. In Experiment 3, conjunctions of form and flicker yielded highly serial search performance. The findings are consistent with the response properties of parvo and magnocellular channels of the early visual system, and suggest that search is most efficient when one of these channels can be filtered completely.


Author(s):  
Megan H. Papesh ◽  
Michael C. Hout ◽  
Juan D. Guevara Pinto ◽  
Arryn Robbins ◽  
Alexis Lopez

AbstractDomain-specific expertise changes the way people perceive, process, and remember information from that domain. This is often observed in visual domains involving skilled searches, such as athletics referees, or professional visual searchers (e.g., security and medical screeners). Although existing research has compared expert to novice performance in visual search, little work has directly documented how accumulating experiences change behavior. A longitudinal approach to studying visual search performance may permit a finer-grained understanding of experience-dependent changes in visual scanning, and the extent to which various cognitive processes are affected by experience. In this study, participants acquired experience by taking part in many experimental sessions over the course of an academic semester. Searchers looked for 20 categories of targets simultaneously (which appeared with unequal frequency), in displays with 0–3 targets present, while having their eye movements recorded. With experience, accuracy increased and response times decreased. Fixation probabilities and durations decreased with increasing experience, but saccade amplitudes and visual span increased. These findings suggest that the behavioral benefits endowed by expertise emerge from oculomotor behaviors that reflect enhanced reliance on memory to guide attention and the ability to process more of the visual field within individual fixations.


Author(s):  
Ulrich Engelke ◽  
Andreas Duenser ◽  
Anthony Zeater

Selective attention is an important cognitive resource to account for when designing effective human-machine interaction and cognitive computing systems. Much of our knowledge about attention processing stems from search tasks that are usually framed around Treisman's feature integration theory and Wolfe's Guided Search. However, search performance in these tasks has mainly been investigated using an overt attention paradigm. Covert attention on the other hand has hardly been investigated in this context. To gain a more thorough understanding of human attentional processing and especially covert search performance, the authors have experimentally investigated the relationship between overt and covert visual search for targets under a variety of target/distractor combinations. The overt search results presented in this work agree well with the Guided Search studies by Wolfe et al. The authors show that the response times are considerably more influenced by the target/distractor combination than by the attentional search paradigm deployed. While response times are similar between the overt and covert search conditions, they found that error rates are considerably higher in covert search. They further show that response times between participants are stronger correlated as the search task complexity increases. The authors discuss their findings and put them into the context of earlier research on visual search.


2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Enkelejda Kasneci ◽  
Alex A. Black ◽  
Joanne M. Wood

To date, few studies have investigated the eye movement patterns of individuals with glaucoma while they undertake everyday tasks in real-world settings. While some of these studies have reported possible compensatory gaze patterns in those with glaucoma who demonstrated good task performance despite their visual field loss, little is known about the complex interaction between field loss and visual scanning strategies and the impact on task performance and, consequently, on quality of life. We review existing approaches that have quantified the effect of glaucomatous visual field defects on the ability to undertake everyday activities through the use of eye movement analysis. Furthermore, we discuss current developments in eye-tracking technology and the potential for combining eye-tracking with virtual reality and advanced analytical approaches. Recent technological developments suggest that systems based on eye-tracking have the potential to assist individuals with glaucomatous loss to maintain or even improve their performance on everyday tasks and hence enhance their long-term quality of life. We discuss novel approaches for studying the visual search behavior of individuals with glaucoma that have the potential to assist individuals with glaucoma, through the use of personalized programs that take into consideration the individual characteristics of their remaining visual field and visual search behavior.


Author(s):  
Nathan Messmer ◽  
Nathan Leggett ◽  
Melissa Prince ◽  
Jason S. McCarley

Gaze linking allows team members in a collaborative visual task to scan separate computer monitors simultaneously while their eye movements are tracked and projected onto each other’s displays. The present study explored the benefits of gaze linking to performance in unguided and guided visual search tasks. Participants completed either an unguided or guided serial search task as both independent and gaze-linked searchers. Although it produced shorter mean response times than independent search, gaze linked search was highly inefficient, and gaze linking did not differentially affect performance in guided and unguided groups. Results suggest that gaze linking is likely to be of little value in improving applied visual search.


2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Alejandro Lleras ◽  
Zhiyuan Wang ◽  
Anna Madison ◽  
Simona Buetti

Recently, Wang, Buetti and Lleras (2017) developed an equation to predict search performance in heterogeneous visual search scenes (i.e., multiple types of non-target objects simultaneously present) based on parameters observed when participants perform search in homogeneous scenes (i.e., when all non-target objects are identical to one another). The equation was based on a computational model where every item in the display is processed with unlimited capacity and independently of one another, with the goal of determining whether the item is likely to be a target or not. The model was tested in two experiments using real-world objects. Here, we extend those findings by testing the predictive power of the equation to simpler objects. Further, we compare the model’s performance under two stimulus arrangements: spatially-intermixed (items randomly placed around the scene) and spatially-segregated displays (identical items presented near each other). This comparison allowed us to isolate and quantify the facilitatory effect of processing displays that contain identical items (homogeneity facilitation), a factor that improves performance in visual search above-and-beyond target-distractor dissimilarity. The results suggest that homogeneity facilitation effects in search arise from local item-to-item interaction (rather than by rejecting items as “groups”) and that the strength of those interactions might be determined by stimulus complexity (with simpler stimuli producing stronger interactions and thus, stronger homogeneity facilitation effects).


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