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Clinical Scenario: Individuals with chronic ankle instability (CAI) typically complete balance training protocols to improve postural control and reduce recurrent injury risk. However, the presence of CAI persists after traditional balance training protocols suggesting that such programs may be missing elements that could be beneficial to patients. Visual occlusion modalities, such as stroboscopic goggles, may be able to augment balance training exercises to further enhance postural control gains in those with CAI. However, a cumulative review of the existing evidence has yet to be conducted. Focused Clinical Question: Does wearing stroboscopic goggles during balance training result in greater improvements to postural control than balance training alone in those with CAI? Summary of Key Findings: All 3 studies indicated that the stroboscopic goggles group had statistically significant improvements in either a measure of static or dynamic postural control relative to the standard balance training group. However, significant improvements were not consistent across all postural control outcomes assessed in the included studies. Clinical Bottom Line: Postural control may improve more in those with CAI when stroboscopic goggles were worn while completing balance training exercises relative to completing balance training exercises alone. Strength of Recommendation: Overall, consistent moderate- to high-quality evidence was present in the 3 studies, suggesting grade C evidence for the use of stroboscopic goggles during balance training in those with CAI. [ABSTRACT FROM AUTHOR]

During visuomotor learning, improvements in motor performance accompany changes in how people use vision. However, the dependencies between altered visual reliance and improvements in motor skill is unclear. The present studies used an online sequence learning task to quantify how changing the availability of visual information affected motor skill learning (study 1) and how changing motor skill affected visual reliance (study 2). Participants used their keyboard to respond to targets falling vertically down a game screen. In study 1 (n = 49), the availability of visual information was altered by manipulating where the targets were visible on the screen. Three experimental groups practiced the task during full or limited vision conditions (when the targets were only visible in specific areas). We hypothesized that limiting visual information would reduce motor learning (i.e., the rate of improvement during training trial blocks). Instead, although participants performed worse during limited vision trials (P < 0.001), there was no difference in learning rate (P = 0.87). In study 2 (n = 119), all participants practiced the task with full vision and their visual reliance (i.e., their performance change between full and limited vision conditions) was quantified before and after training. We hypothesized that with motor learning, visual reliance on future targets would increase, whereas visual reliance on the current targets would decrease. The results of study 2 partially support our hypotheses with visual reliance decreasing for all visual areas (P < 0.001). Together, the results suggest changing motor skill alters how people use vision, but changing visual availability does not affect motor learning. NEW & NOTEWORTHY: Previous research has established how people use visual information changes with motor learning. However, the dependencies of these two processes on each other are unclear. We find that limiting the availability of visual information degrades motor performance but not motor learning. We also find that motor learning reduces the impact of limiting the availability of visual information on motor performance. Together, these results suggest that how people use visual information depends on their motor skill. [ABSTRACT FROM AUTHOR]

Background: This study contributes to expanding the existing literature on learning technical skills in youth soccer by comparing the effectiveness of different training approaches in the development of passing skills. The ecological-dynamic approach, which emphasizes the continuous and adaptive interaction between the athlete and the environment, is analyzed in comparison to the traditional prescriptive approach, which relies on predefined techniques and exercises. The aim of the study is to determine which of the two approaches is more effective in improving the performance of young soccer players. Methods: Thirty players (age 12 ± 1.2 years) were randomly assigned to two groups: the ecological-dynamic group (ECG) and a control group (CON). Both groups underwent an eight-week training program with equal sessions. The ECG group's training focused on adjusting constraints like the learning environment, game rules, and visual restrictions to boost adaptability and problem-solving skills. The CON group followed a traditional prescriptive approach with specific instructions, goal setting, immediate feedback, and structured exercise progression. Passing abilities were evaluated before and after the program using the Loughborough Soccer Passing Test, with a retention test administered five weeks later. Descriptive statistics, including mean values and percentage improvements, were used. A repeated measures ANOVA compared differences between the groups. Results: The analysis revealed a significant Occasion × Group interaction for all performance variables, indicating that the ECG group experienced greater improvements than the CON group. Specifically, the ECG group showed significant reductions in Trial Time (p = 0.001, ηp2 = 0.6), Penalty Time (p = 0.016, ηp2 = 0.4), and Overall Performance (p = 0.011, ηp2 = 0.8) from pre-test to post-test. However, these improvements did not persist into the retention test (p = 0.131, p = 0.792, and p = 0.192, respectively). The CON group also improved significantly in Trial Time (p = 0.003), Penalty Time (p = 0.002), and Overall Performance (p = 0.001) from pre-test to post-test, but with smaller effect sizes and no sustained gains at retention. Conclusions: The ecological-dynamic approach (EDG) has proven to be more effective in enhancing passing skills compared to the traditional prescriptive approach (CON). Although both methods led to performance improvements, the EDG group achieved more significant progress. [ABSTRACT FROM AUTHOR]

Background: This study contributes to expanding the existing literature on learning technical skills in youth soccer by comparing the effectiveness of different training approaches in the development of passing skills. The ecological-dynamic approach, which emphasizes the continuous and adaptive interaction between the athlete and the environment, is analyzed in comparison to the traditional prescriptive approach, which relies on predefined techniques and exercises. The aim of the study is to determine which of the two approaches is more effective in improving the performance of young soccer players. Methods: Thirty players (age 12 ± 1.2 years) were randomly assigned to two groups: the ecological-dynamic group (ECG) and a control group (CON). Both groups underwent an eight-week training program with equal sessions. The ECG group’s training focused on adjusting constraints like the learning environment, game rules, and visual restrictions to boost adaptability and problem-solving skills. The CON group followed a traditional prescriptive approach with specific instructions, goal setting, immediate feedback, and structured exercise progression. Passing abilities were evaluated before and after the program using the Loughborough Soccer Passing Test, with a retention test administered five weeks later. Descriptive statistics, including mean values and percentage improvements, were used. A repeated measures ANOVA compared differences between the groups. Results: The analysis revealed a significant Occasion × Group interaction for all performance variables, indicating that the ECG group experienced greater improvements than the CON group. Specifically, the ECG group showed significant reductions in Trial Time (p = 0.001, ηp2 = 0.6), Penalty Time (p = 0.016, ηp2 = 0.4), and Overall Performance (p = 0.011, ηp2 = 0.8) from pre-test to post-test. However, these improvements did not persist into the retention test (p = 0.131, p = 0.792, and p = 0.192, respectively). The CON group also improved significantly in Trial Time (p = 0.003), Penalty Time (p = 0.002), and Overall Performance (p = 0.001) from pre-test to post-test, but with smaller effect sizes and no sustained gains at retention. Conclusions: The ecological-dynamic approach (EDG) has proven to be more effective in enhancing passing skills compared to the traditional prescriptive approach (CON). Although both methods led to performance improvements, the EDG group achieved more significant progress.

Simple Summary: Higher levels of our visual systems process information from broad regions of our visual space, recognising scenes, objects, and faces, often regardless of their location. In contrast, earlier levels of our visual system respond to small detailed visual features, such as lines oriented in a certain direction and at precise spatial locations. High- and low-level visual areas are reciprocally connected, and visual perception emerges from recurrent neuronal computations between these areas. When tuning our brain imaging analysis to the spatial precision of the top-down connections from higher- to lower-level visual areas, do higher areas project their coarse spatial tuning or is this processing translated to the high-precision coding of the lower-level target region they are projecting to? For example, while neurons in early visual areas respond to the precise location of a cup on your desk, and higher-level areas continue to respond to the cup even when the cup is slightly moved, how is communication between higher-level visual areas and lower-level visual areas resolved? We hypothesised that the more generalised contextual information of 'the cup is somewhere here' is broadcast to cells in lower visual areas that would otherwise not respond, and those that are responding with the information 'an object boundary is precisely detected here' can now confirm whether it is consistent with the explanation that this contour belongs to a cup. In line with this hypothesis, we found that early visual areas receive feedback information that generalises across images in which the features have been spatially displaced. The data inform our understanding of how early visual areas are modulated by higher areas during visual perception. Neurons in the primary visual cortex (V1) receive sensory inputs that describe small, local regions of the visual scene and cortical feedback inputs from higher visual areas processing the global scene context. Investigating the spatial precision of this visual contextual modulation will contribute to our understanding of the functional role of cortical feedback inputs in perceptual computations. We used human functional magnetic resonance imaging (fMRI) to test the spatial precision of contextual feedback inputs to V1 during natural scene processing. We measured brain activity patterns in the stimulated regions of V1 and in regions that we blocked from direct feedforward input, receiving information only from non-feedforward (i.e., feedback and lateral) inputs. We measured the spatial precision of contextual feedback signals by generalising brain activity patterns across parametrically spatially displaced versions of identical images using an MVPA cross-classification approach. We found that fMRI activity patterns in cortical feedback signals predicted our scene-specific features in V1 with a precision of approximately 4 degrees. The stimulated regions of V1 carried more precise scene information than non-stimulated regions; however, these regions also contained information patterns that generalised up to 4 degrees. This result shows that contextual signals relating to the global scene are similarly fed back to V1 when feedforward inputs are either present or absent. Our results are in line with contextual feedback signals from extrastriate areas to V1, describing global scene information and contributing to perceptual computations such as the hierarchical representation of feature boundaries within natural scenes. [ABSTRACT FROM AUTHOR]

Motion planning for autonomous vehicles remains a challenge in urban road environments with occlusions. In this study, we present a motion planning framework that prioritizes safety, comfort, and efficiency to enable autonomous vehicles to navigate safely through urban roads with occlusions. Our solution consists of three main components: local path planning, trajectory planning, and speed planning. First, based on the improved Artificial Potential Field to generate the local path, then the optimal trajectory is solved in the S-L coordinate with the local path as the reference line. Subsequently, the potential risk probability of the occluded area is incorporated into the incomplete information static game framework and implement speed planning based on the game results and the proposed vehicle “safe driving” to complete the collision avoidance between the autonomous vehicle and visible or obscured dynamic traffic participants. In high pedestrian traffic scenarios, simulation verification shows that the proposed model enhances autonomous vehicle comfort levels by about 32% $\sim $ 48% compared to the baseline method utilizing automatic emergency brake system (AEB). We also conducted simulation verification of the proposed model in overtaking and left-turning traffic scenarios, comparing it with other models. The results demonstrate that our proposed model ensures safe autonomous driving in traffic scenario with occlusions while maintaining comfort and efficiency.

Purpose: Recent work involving reaching and aiming tasks provides evidence that an internal focus results in less error than an external focus when visual information is removed. The purpose of this study was to extend these findings by determining how an internal and external focus impact motor performance during a balancing task for adults with and without visual occlusion. Method: Thirty-two undergraduate students were randomly assigned to perform the task with or without visual occlusion. Participants balanced on a stability platform during four familiarization trials, three internal focus trials, and three external focus trials. Results: A significant Focus x Vision interaction indicated the group without visual occlusion had significantly lower root mean square error (RMSE) with an external focus, whereas the group with visual occlusion had lower RMSE with an internal focus. Conclusions: These findings indicate that for tasks that rely on online sensory feedback, such as balancing, the optimal attentional focus may be dependent on the dominant type of sensory feedback that is available. [ABSTRACT FROM AUTHOR]

Background: Visual occlusion reduces players' field of vision and directly affects their physical, technical and positional performance. Therefore, it is important to understand how visual perception is affected, and whether training with visual occlusion leads to an improvement in performance. Objective: This study aimed to examine whether training with visual occlusion could improve technical skills in young football players. Methods: Thirty male Under-14 amateur football players were randomly assigned to a visual occlusion group (OCC; n = 15) and a control group (CON; n = 15). In addition to the conventional training program, the OCC performed visual occlusion training sessions using spatial occlusion goggles that removed the sight of the participants' limbs and lower body. The CON performed only the conventional training program. The study consisted of a pre-test, two months of training intervention and a post-test. Contextualised technical skills were tested using the Loughborough Soccer Passing Test. Results: Both OCC (p = .21) and CON (p = .43) did not change Trial performance. However, the OCC experienced small-to-moderate improvements in Penalty time (p = .002; d = 0.51, 95% CI [0.10, 0.70]) and Global performance (p = .005, d = 0.44, 95% CI [0.05, 0.66]). The CON did not show changes in Penalty time (p = .61) and Global performance (p = .89) variables. A significant moment × group interaction was found in Penalty time (p = .016, ηp ² = .19, 95% CI [.03, .48]) and Global performance (p = .011, ηp ² = .21, 95% CI [.01, .45]). Conclusions: The OCC has shown a significant reduction in the amount of time required to complete the trial and the Penalty time. These results suggest that incorporating visual occlusion as a paradigm into a training program for football players may positively impact their technical skills. [ABSTRACT FROM AUTHOR]

Despite extensive research on passerine reproduction, it remains difficult to predict which traits of individuals, nesting populations and landscapes drive extrapair paternity (EPP). Two broad categories of drivers, habitat structure and population level factors, have been considered separately or at a single spatial or temporal scale. We used a 6-year nesting data set of scissor-tailed flycatcher, Tyrannus forficatus , which have high rates of cuckoldry (73% of nests, 59% of nestlings), to explore how nest density, breeding synchrony, habitat structure and clutch initiation date affect EPP rates. We further considered synchrony at two temporal and habitat structure at two spatial scales. We predicted that visual occlusion from vertical habitat structuring on breeding territories would allow extrapair males to go unnoticed and provide cover for extrapair copulations. Predictions for effects of nest density and fertility synchrony were double-edged: EPP may either increase as extrapair mate availability and ease of comparison with social mates increases or decrease as social mates increase their efforts to assure paternity. Using Bayesian techniques, we found a combination of population level factors and habitat structure, including interactions among the latter, at different scales best accounted for variation in EPP. EPP declined with increasing population synchrony. Variation in EPP was also explained by fine-scale habitat measures, decreasing with increasing nest tree diameter at breast height and woody vegetation cover but increasing with tree density. Notably, EPP increased with a coarse-scale habitat measure, linear extent of fence or powerline, suggesting a role for human alteration of habitat. Fences are used as communal perches by neighbours and floater males, potentially increasing interactions between asynchronous individuals. Our study demonstrates that breeding synchrony influences the probability of EPP and that habitat structure on individual territories is a strong predictor of paternity that acts independently of breeding density or synchrony at our scale of measurement. • We explore factors influencing cuckoldry in scissor-tailed flycatchers across 6 years. • Cuckoldry increased with populationwide fertility synchrony. • Cuckoldry was not related to spatial distribution of nests. • Cuckoldry increased with tree number and powerline/fence length and low shrub cover. • These correlates may impact cuckoldry via their effects on male mate guarding. [ABSTRACT FROM AUTHOR]

Neurons in the primary visual cortex (V1) receive sensory inputs that describe small, local regions of the visual scene and cortical feedback inputs from higher visual areas processing the global scene context. Investigating the spatial precision of this visual contextual modulation will contribute to our understanding of the functional role of cortical feedback inputs in perceptual computations. We used human functional magnetic resonance imaging (fMRI) to test the spatial precision of contextual feedback inputs to V1 during natural scene processing. We measured brain activity patterns in the stimulated regions of V1 and in regions that we blocked from direct feedforward input, receiving information only from non-feedforward (i.e., feedback and lateral) inputs. We measured the spatial precision of contextual feedback signals by generalising brain activity patterns across parametrically spatially displaced versions of identical images using an MVPA cross-classification approach. We found that fMRI activity patterns in cortical feedback signals predicted our scene-specific features in V1 with a precision of approximately 4 degrees. The stimulated regions of V1 carried more precise scene information than non-stimulated regions; however, these regions also contained information patterns that generalised up to 4 degrees. This result shows that contextual signals relating to the global scene are similarly fed back to V1 when feedforward inputs are either present or absent. Our results are in line with contextual feedback signals from extrastriate areas to V1, describing global scene information and contributing to perceptual computations such as the hierarchical representation of feature boundaries within natural scenes.

For decades, both empirical and theoretical models have been proposed to explain the patterns and mechanisms of collective decision-making (CDM). The most-studied CDM scenario is the best-of-n problem in a static environment. However, natural environments are typically dynamic. In dynamic environments, the visual occlusions produced by other members of a large-scale group are also common. Hence, some agents of a group are less informed than others, and their state uncertainties increase. This paper develops a new model referred to as the generalized Ising model with dynamic confidence (GIM-C) to reduce the state uncertainty induced by visual occlusions. The proposed model first estimates the expected rewards of possible actions with dynamic confidence weighting. It then gives the probability of choosing each action based on the generalized Ising model with an external field defined by the last stage's results. Numerical simulations demonstrate that GIM-C shares the key feature of social cohesion with previous CDM models. Furthermore, in order to illustrate the efficiency of the proposed GIM-C, the collecting foraging task is considered, where a large-scale group of agents is required to obtain rewards with the presence of a dynamic predator and visual occlusions. The good performance of GIM-C in the collecting foraging task demonstrates that dynamic confidence weighting is efficient in reducing the state uncertainty introduced by visual occlusions. The proposed GIM-C also demonstrates the importance of enhancing the influence of informed agents in CDM problems in a dynamic environment with visual occlusions. [ABSTRACT FROM AUTHOR]

In humans, extrastriate visual areas are strongly activated by symmetry. However, perfect symmetry is rare in natural visual images. Recent findings showed that when parts of a symmetric shape are presented at different points in time the process relies on a perceptual memory buffer. Does this temporal integration need a retinotopic reference frame? For the first time we tested integration of parts both in the temporal and spatial domain, using a non-retinotopic frame of reference. In Experiment 1, an irregular polygonal shape (either symmetric or asymmetric) was partly occluded by a rectangle for 500 ms (T1). The rectangle moved to the opposite side to reveal the other half of the shape, whilst occluding the previously visible half (T2). The reference frame for the object was static: the two parts stimulated retinotopically corresponding receptive fields (revealed over time). A symmetry-specific ERP response from ~300 ms after T2 was observed. In Experiment 2 dynamic occlusion was combined with an additional step at T2: the new half-shape and occluder were rotated by 90°. Therefore, there was a moving frame of reference and the retinal correspondence between the two parts was disrupted. A weaker but significant symmetry-specific response was recorded. This result extends previous findings: global symmetry representation can be achieved in extrastriate areas non-retinotopically, through integration in both temporal and spatial domain. [ABSTRACT FROM AUTHOR]

Current models of object recognition are based on spatial representations build from object features that are simultaneously present in the retinal image. However, one can recognize an object when it moves behind a static occlude, and only a small fragment of its shape is visible through a slit at a given moment in time. Such anorthoscopic perception requires spatiotemporal integration of the successively presented shape parts during slit-viewing. Human fMRI studies suggested that ventral visual stream areas represent whole shapes formed through temporal integration during anorthoscopic perception. To examine the time course of shape-selective responses during slit-viewing, we recorded the responses of single inferior temporal (IT) neurons of rhesus monkeys to moving shapes that were only partially visible through a static narrow slit. The IT neurons signaled shape identity by their response when that was cumulated across the duration of the shape presentation. Their shape preference during slit-viewing equaled that for static, whole-shape presentations. However, when analyzing their responses at a finer time scale, we showed that the IT neurons responded to particular shape fragments that were revealed by the slit. We found no evidence for temporal integration of slit-views that result in a whole-shape representation, even when the monkey was matching slit-views of a shape to static whole-shape presentations. These data suggest that, although the temporally integrated response of macaque IT neurons can signal shape identity in slit-viewing conditions, the spatiotemporal integration needed for the formation of a whole-shape percept occurs in other areas, perhaps downstream to IT. [ABSTRACT FROM AUTHOR]

Introduction: The effect of central vision occlusion on two-hand coordination tasks is assessed in previous studies. However, the effect of peripheral vision on these tasks is not clearly identified; therefore, the purpose of this study was to investigate the effect of limitation of peripheral vision on two-hand coordination tasks. Material and Methods: Seven right-handed and right eye-dominant girl students with a mean age of 24.00 ± 3.46 years participated in this study. Subjects tested under four experimental conditions including peripheral vision limitation of the position of right hand, left hand, and both hands, and no peripheral limitations of hand position in the two-handed Vienna coordination task with four tries for each condition. The data were analyzed using 1 × 4 repeated measures ANOVA. Results: All three conditions of visual peripheral limitation showed less errors than the conditions without visual limitation (P < 0.05). However, no significant difference was observed between four experimental conditions in the variable of total time (P > 0.05). Conclusion: It seems that the visual peripheral limitation, as an environmental constraint, may increase the focus and attention of people in the two-hand coordination task.

Objective: To assess the attentional demand of different contextual factors in driving.Background: The attentional demand on the driver varies with the situation. One approach for estimating the attentional demand, via spare capacity, is to use visual occlusion.Method: Using a 3 × 5 within-subjects design, 33 participants drove in a fixed-base simulator in three scenarios (i.e., urban, rural, and motorway), combined with five fixed occlusion durations (1.0, 1.4, 1.8, 2.2, and 2.6 s). By pressing a microswitch on a finger, the driver initiated each occlusion, which lasted for the same predetermined duration within each trial. Drivers were instructed to occlude their vision as often as possible while still driving safely.Results: Stepwise logistic regression per scenario indicated that the occlusion predictors varied with scenario. In the urban environment, infrastructure-related variables had the biggest influence, whereas the distance to oncoming traffic played a major role on the rural road. On the motorway, occlusion duration and time since the last occlusion were the main determinants.Conclusion: Spare capacity is dependent on the scenario, selected speed, and individual factors. This is important for developing workload managers, infrastructural design, and aspects related to transfer of control in automated driving.Application: Better knowledge of the determinants of spare capacity in the road environment can help improve workload managers, thereby contributing to more efficient and safer interaction with additional tasks. [ABSTRACT FROM AUTHOR]

The purpose of this study was to analyse swimmers' perceptual judgements of a simulated time-to-contact task in freestyle swimming relays. The study sample consisted of 31 national-level swimmers of both genders (n = 18 males, 17.22 ± 1.95 yrs.; n = 13 females, 14.61 ±.76 yrs.). Participants were asked to watch two videos corresponding to the last course of a given swimmer during a competition of 4 × 100 m and 4 × 200 m freestyle events. These videos were presented with temporal occlusion correspondent to predetermined approaching distances (7.5, 5.0, and 2.5 m). Participants were required to simulate a typical position in standby for exiting the block and estimate the time-to-contact of the incoming swimmer by pressing a switch. A Wilcoxon test was performed to determine differences between time-to-contact and real contact time. The results showed that estimation of time-to-contact was generally lower than real contact time at all approaching distances (with occlusion) and for both genders (p <.05), except at a 7.5-m distance in the men's 4 × 200 m (p =.744; r =.09) and at 5.0 m in both the 4 × 100 m and 4 × 200 m for the female group (p =.279, r =.22 for 4 × 100 m; p =.2453, r =.17 for 4 × 200 m). The larger variation (Δ) between estimation and real contact time was found at a 7.5 m occlusion distance in the female 4 × 100 m (p <.001; r =.82). Swimmers tend to underestimate the time-to-contact of the incoming swimmer, in the context of a simulated relay race. Taken together, these results highlight the importance of perceptual abilities development in swimmers to optimize their technique and effectiveness during relay starts. [ABSTRACT FROM AUTHOR]

Abstract When symmetry is present in the retinal image, a symmetry-sensitive network in the extrastriate visual areas activates, and response magnitude scales with degree of regularity. Is this activation driven by the regularity in the image, or can the network recover regularity of an object? We investigated whether the network responds to bilateral symmetry for dynamically occluded shapes, and thus responds to symmetry in the object. The stimulus was an irregular shape partly occluded by a rectangle. After 500 ms, the rectangle was displaced to the other side, occluding the previously visible half, and revealing the other half for 1000 ms. Therefore, no symmetry was present in the image at any point in time. Exp.1 and Exp.2 used vertical and horizontal axis of reflection, and in Exp. 3 there was no occluder. Participants could detect symmetry with >80% accuracy. More importantly, ERP analysis showed a symmetry-specific response from ∼300 ms after presentation of the second half of the shape. When integration was made from halves of asymmetric whole shapes (Exp.4), and when symmetry was not task-relevant (Exp.5), no symmetry response was recorded. The results show, for the first time, an electrophysiological evidence of symmetry representation in the brain obtained by assembling information over time into a unitary gestalt. The integration process occurs when observers look for symmetric matches between the parts, and only if these are perceived as belonging to the same object. Highlights • A symmetry-sensitive network in the extrastriate visual areas reflects the perceptual coding of visual regularity in the retinal image. • This study investigated whether the symmetry-network can process the dynamic integration of transient (asymmetric) parts to give a holistic representation of symmetry (at object-level). • Results from three experiments showed that a symmetry-ERP response was generated when two separate (asymmetric) parts of a shape were viewed at different timepoints (Experiment 1, 2, and 3). • Another experiment confirmed that this process occurs only if the parts are perceived as belonging to the same object (Experiment 4). • Finally, the integration process occurs when observers look for symmetric matches between the parts (i.e. active symmetry discrimination) (Experiment 5). [ABSTRACT FROM AUTHOR]

In this work, we contribute to the current understanding of human behaviors in telepresence when visual occlusions are introduced in a remote collaboration context. Occlusions can occur when users in remote locations are engaged in physical collaborative tasks. This can yield to frustration and inefficient collaboration between the collaborators. In this work, we aim to design a better user interface to improve remote collaboration experience. We conducted two human-subjects experiments to investigate the following interlinked research questions: (a) what are the impacts of occlusion on remote collaborations, and (b) can an autonomous handling of occlusions improve telepresence collaboration experience for remote users? Results from our preliminary experiment demonstrate that occlusions introduce a significant social interference that necessitates collaborators to reorient or reposition themselves. Subsequently, we conducted a main experiment to evaluate the efficacy of autonomous occlusion handling for remote users. Results from this experiment indicate that the use of an autonomous controller yields a remote user experience that is more comparable (in terms of their vocal non-verbal behaviors ["The vocal non-verbal behaviour includes all spoken cues that surround the verbal message and influence its actual meaning." (Vinciarelli in Image Vis Comput 27(12):1743-1759, 2009)], task performance and perceived workload) to collaborations performed by two co-located parties. Finally, we discuss the implications of a better controller design for similar robot-mediated social interactions. [ABSTRACT FROM AUTHOR]

Objective To investigate the extent of a driver’s mental model with irrevocable visual occlusion and analysing the distance to crash. Background Drivers have a mental model of the immediate surroundings which allows them to predict their own as well as others’ travel paths. To navigate safely through traffic, this mental model has to be updated frequently to remain valid. In between information sampling events, the mental model will become outdated over time, as the traffic system is dynamic. Method A simulator study with 22 participants was conducted to investigate the information decay in the mental model. This was implemented by extending visual occlusion until the driver collided with another vehicle or ran off the road, thus providing an estimate of how long it takes until the mental model becomes obsolete. Results An analysis of variance with the factors curve direction, curve radius and traffic showed that curve radius did not influence the distance to crash. Without traffic, drivers veered off the road sooner in right curves. Adding traffic eliminated this difference. Traffic ahead led to a shortened distance to crash. Compared to a tangential travel path from the current lateral position at the time of the occlusion, drivers crashed on average 2.6 times later than they would have, had they not had any mental model of the situation. Conclusions The drivers’ mental representation of the future situation seems to include information on how to act, to alleviate deviations in yaw angle, including and considering the presence of other road users. [ABSTRACT FROM AUTHOR]

Our interaction with objects is facilitated by the availability of visual feedback. Here, we investigate how and when visual feedback affects the way we grasp an object. Based on the main views on grasping (reach-and-grasp and double-pointing views), we designed four experiments to test: (1) whether the availability of visual feedback influences the digits independently, and (2) whether the absence of visual feedback affects the initial part of the movement. Our results show that occluding (part of) the hand’s movement path influences the movement trajectory from the beginning. Thus, people consider the available feedback when planning their movements. The influence of the visual feedback depends on which digit is occluded, but its effect is not restricted to the occluded digit. Our findings indicate that the control mechanisms are more complex than those suggested by current views on grasping. [ABSTRACT FROM AUTHOR]

This paper shows that it is possible to estimate the subjective precision (inverse variance) of Bayesian beliefs during oculomotor pursuit. Subjects viewed a sinusoidal target, with or without random fluctuations in its motion. Eye trajectories and magnetoencephalographic (MEG) data were recorded concurrently. The target was periodically occluded, such that its reappearance caused a visual evoked response field (ERF). Dynamic causal modelling (DCM) was used to fit models of eye trajectories and the ERFs. The DCM for pursuit was based on predictive coding and active inference, and predicts subjects' eye movements based on their (subjective) Bayesian beliefs about target (and eye) motion. The precisions of these hierarchical beliefs can be inferred from behavioural (pursuit) data. The DCM for MEG data used an established biophysical model of neuronal activity that includes parameters for the gain of superficial pyramidal cells, which is thought to encode precision at the neuronal level. Previous studies (using DCM of pursuit data) suggest that noisy target motion increases subjective precision at the sensory level: i.e., subjects attend more to the target's sensory attributes. We compared (noisy motion-induced) changes in the synaptic gain based on the modelling of MEG data to changes in subjective precision estimated using the pursuit data. We demonstrate that imprecise target motion increases the gain of superficial pyramidal cells in V1 (across subjects). Furthermore, increases in sensory precision – inferred by our behavioural DCM – correlate with the increase in gain in V1, across subjects. This is a step towards a fully integrated model of brain computations, cortical responses and behaviour that may provide a useful clinical tool in conditions like schizophrenia. [ABSTRACT FROM AUTHOR]

Objective: We studied the utility of occlusion distance as a function of task-relevant event density in realistic traffic scenarios with self-controlled speed.Background: The visual occlusion technique is an established method for assessing visual demands of driving. However, occlusion time is not a highly informative measure of environmental task-relevant event density in self-paced driving scenarios because it partials out the effects of changes in driving speed.Method: Self-determined occlusion times and distances of 97 drivers with varying backgrounds were analyzed in driving scenarios simulating real Finnish suburban and highway traffic environments with self-determined vehicle speed.Results: Occlusion distances varied systematically with the expected environmental demands of the manipulated driving scenarios whereas the distributions of occlusion times remained more static across the scenarios. Systematic individual differences in the preferred occlusion distances were observed. More experienced drivers achieved better lane-keeping accuracy than inexperienced drivers with similar occlusion distances; however, driving experience was unexpectedly not a major factor for the preferred occlusion distances.Conclusion: Occlusion distance seems to be an informative measure for assessing task-relevant event density in realistic traffic scenarios with self-controlled speed. Occlusion time measures the visual demand of driving as the task-relevant event rate in time intervals, whereas occlusion distance measures the experienced task-relevant event density in distance intervals.Application: The findings can be utilized in context-aware distraction mitigation systems, human-automated vehicle interaction, road speed prediction and design, as well as in the testing of visual in-vehicle tasks for inappropriate in-vehicle glancing behaviors in any dynamic traffic scenario for which appropriate individual occlusion distances can be defined. [ABSTRACT FROM AUTHOR]

To solve the problem of the measurement information loss caused by occlusion of the field of view in line-structured light measurement, a vision occlusion solution of the line-structured light measurement system based on a plane mirror is proposed in this work. In the system, a symmetrical structure between real and virtual images was created by the mirror. A checkerboard with a light stripe and its mirror image were captured by the camera in an image. The centers of the light stripe and its mirror image were corrected by the vanishing point constraint, and a calibration method of the free plane target was used to calibrate the real and virtual light planes. The real and virtual point clouds of the object were obtained by scanning with a linear guide. According to the ideal reflection model of the mirror, the real and virtual point clouds of the object were transformed into a common coordinate system, and an iterative closest point (ICP) algorithm was used to realize fine registration. As a result, the occluded parts can be compensated for each other. Compared with a standard ball, the mean/maximum absolute error of the measurement was 0.2553/0.3276 mm. The experimental results revealed that the proposed method can obtain the complete surface of the object, thus effectively solving the occlusion problem in the line-structured light measurement, and reducing the loss of the measurement information, which can meet the industrial measurement requirements. [ABSTRACT FROM AUTHOR]

Research in cycling safety seeks to better understand bicycle-related crashes and injuries. The present naturalistic cycling study contributes to this research by collecting data about bicyclists’ behavior and impressions of safety–critical situations, information unavailable in traditional data sources (e.g., accident databases, observational studies). Naturalistic data were collected from 16 bicyclists (8 female; M = 39.1 years, SD = 11.4 years) who rode instrumented bicycles for two weeks. Bicyclists were instructed to report all episodes in which they felt uncomfortable while riding (subjective risk perception), even if they didn’t fall. After data collection, the bicyclists were interviewed in detail regarding their self-reported safety–critical events. Environmental conditions were also recorded via video (e.g., road surface, weather). In total, 63 safety–critical events (56 non-crashes, 7 crashes) were reported by the bicyclists, mainly due to interactions with other road users – but also due to poorly maintained infrastructure. In low-visibility conditions, vehicle-bicycle and bicycle-bicycle events were the most uncomfortable for the bicyclists. Self-reported pedestrian–bicycle events primarily consisted of pedestrians starting to cross the bicycle path without looking. With one exception, all crashes found in the study belonged to poorly maintained road and infrastructure. In particular, construction work or obstacles in the bicycle path were reported as uncomfortable and annoying by the bicyclists. This study shows how naturalistic data and bicyclists’ interviews together can provide a more informative picture of safety–critical situations experienced by the bicyclist than traditional data sources can. [ABSTRACT FROM AUTHOR]

The classical rubber hand illusion is induced by an experimenter (eg stimulation with a brush) and usually realized with some sort of visual occlusion. Here, we demonstrate a new phenomenon: the self-induced rubber hand illusion. It is possible to elicit the feeling of a third hand without any help from an experimenter and under conditions of no occlusion. The findings are discussed within the context of neural plasticity. [ABSTRACT FROM AUTHOR]

Mantises (Mantodea, Mantidae) visually detect insect prey and capture it by a ballistic strike of their specialized forelegs. We tested predatory responses of female mantis, Sphodromantis viridis, to computer generated visual stimuli, to determine the effects of (i) target size and velocity (ii) discrete changes in target size and (iii) visual occlusion. Maximal predatory responses were elicited by stimuli that (i) subtended ~20°-23° horizontally and ~16°-19° vertically, at the eye, and moved across the screen at angular velocities of ~46°-119°/s, (ii) increased in size in a stepwise manner, with step duration ≥0.8 s, while stimuli decreasing in size elicited only peering movements, (iii) Stimuli disappearing gradually behind a virtual occlusion elicited one or more head saccades but not actual interception. [ABSTRACT FROM AUTHOR]