Effects of older age on visual and self-motion sensory cue integration in navigation.

Older adults demonstrate impairments in navigation that cannot be explained by general cognitive and motor declines. Previous work has shown that older adults may combine sensory cues during navigation differently than younger adults, though this work has largely been done in dark environments where sensory integration may differ from full-cue environments. Here, we test whether aging adults optimally combine cues from two sensory systems critical for navigation: vision (landmarks) and body-based self-motion cues. Participants completed a homing (triangle completion) task using immersive virtual reality to offer the ability to navigate in a well-lit environment including visibility of the ground plane. An optimal model, based on principles of maximum-likelihood estimation, predicts that precision in homing should increase with multisensory information in a manner consistent with each individual sensory cue's perceived reliability (measured by variability). We found that well-aging adults (with normal or corrected-to-normal sensory acuity and active lifestyles) were more variable and less accurate than younger adults during navigation. Both older and younger adults relied more on their visual systems than a maximum likelihood estimation model would suggest. Overall, younger adults' visual weighting matched the model's predictions whereas older adults showed sub-optimal sensory weighting. In addition, high inter-individual differences were seen in both younger and older adults. These results suggest that older adults do not optimally weight each sensory system when combined during navigation, and that older adults may benefit from interventions that help them recalibrate the combination of visual and self-motion cues for navigation.

Using virtual reality to assess dynamic self-motion and landmark cues for spatial updating in children and adults.

The relative contribution of different sources of information for spatial updating - keeping track of one's position in an environment - has been highly debated. Further, children and adults may differ in their reliance on visual versus body-based information for spatial updating. In two experiments, we tested children (age 10-12 years) and young adult participants on a virtual point-to-origin task that varied the types of self-motion information available for translation: full-dynamic (walking), visual-dynamic (controller induced), and no-dynamic (teleporting). In Experiment 1, participants completed the three conditions in an indoor virtual environment with visual landmark cues. Adults were more accurate in the full- and visual-dynamic conditions (which did not differ from each other) compared to the no-dynamic condition. In contrast, children were most accurate in the visual-dynamic condition and also least accurate in the no-dynamic condition. Adults outperformed children in all conditions. In Experiment 2, we removed the potential for relying on visual landmarks by running the same paradigm in an outdoor virtual environment with no geometrical room cues. As expected, adults' errors increased in all conditions, but performance was still relatively worse in teleporting. Surprisingly, children showed overall similar accuracy and patterns across locomotion conditions to adults. Together, the results support the importance of dynamic translation information (either visual or body-based) for spatial updating across both age groups, but suggest children may be more reliant on visual information than adults.

A comparison of virtual locomotion methods in movement experts and non-experts: testing the contributions of body-based and visual translation for spatial updating.

Both visual and body-based (vestibular and proprioceptive) information contribute to spatial updating, or the way a navigator keeps track of self-position during movement. Research has tested the relative contributions of these sources of information and found mixed results, with some studies demonstrating the importance of body-based information, especially for translation, and some demonstrating the sufficiency of visual information. Here, we invoke an individual differences approach to test whether some individuals may be more dependent on certain types of information compared to others. Movement experts tend to be dependent on motor processes in small-scale spatial tasks, which can help or hurt performance, but it is unknown if this effect extends into large-scale spatial tasks like spatial updating. In the current study, expert dancers and non-dancers completed a virtual reality point-to-origin task with three locomotion methods that varied the availability of body-based and visual information for translation: walking, joystick, and teleporting. We predicted decrements in performance in both groups as self-motion information was reduced, and that dancers would show a larger cost. Surprisingly, both dancers and non-dancers performed with equal accuracy in walking and joystick and were impaired in teleporting, with no large differences between groups. We found slower response times for both groups with reductions in self-motion information, and minimal evidence for a larger cost for dancers. While we did not see strong dance effects, more participation in spatial activities related to decreased angular error. Together, the results suggest a flexibility in reliance on visual or body-based information for translation in spatial updating that generalizes across dancers and non-dancers, but significant decrements associated with removing both of these sources of information.

Spatial Reference Frame but Neither Age nor Gender Predict Performance on a Water-Level Task in 8- to 11-Year-Old Children.

Successful performance on the water-level task, a common measure of spatial perception, requires adopting an environmental, rather than object-centered, spatial frame of reference. Use of this strategy has not been systematically studied in prepubertal children, a developmental period during which individual differences in spatial abilities start to emerge. In this study, children aged 8 to 11 reported their age and gender, completed a paper-and-pencil water-level task, and drew a map of their neighborhood to assess spontaneous choice of spatial frame of reference. Results showed a surprising lack of age or gender difference in water-level performance, but a significant effect of spatial frame of reference. Although they made up only a small portion of the sample, children who drew allocentric maps had the highest water-level score, with very high accuracy. These results suggest that children who adopt environmental-based reference frames when depicting their familiar environment may also use environmental-based reference frame strategies to solve spatial perception tasks, thereby facilitating highly accurate performance.

Going the distance and beyond: simulated low vision increases perception of distance traveled during locomotion.

In a series of experiments, we tested the hypothesis that severely degraded viewing conditions during locomotion distort the perception of distance traveled. Some research suggests that there is little-to-no systematic error in perceiving closer distances from a static viewpoint with severely degraded acuity and contrast sensitivity (which we will refer to as blur). However, several related areas of research-extending across domains of perception, attention, and spatial learning-suggest that degraded acuity and contrast sensitivity would affect estimates of distance traveled during locomotion. In a first experiment, we measured estimations of distance traveled in a real-world locomotion task and found that distances were overestimated with blur compared to normal vision using two measures: verbal reports and visual matching (Experiments 1 a, b, and c). In Experiment 2, participants indicated their estimate of the length of a previously traveled path by actively walking an equivalent distance in a viewing condition that either matched their initial path (e.g., blur/blur) or did not match (e.g., blur/normal). Overestimation in blur was found only when participants learned the path in blur and made estimates in normal vision (not in matched blur learning/judgment trials), further suggesting a reliance on dynamic visual information in estimates of distance traveled. In Experiment 3, we found evidence that perception of speed is similarly affected by the blur vision condition, showing an overestimation in perception of speed experienced in wheelchair locomotion during blur compared to normal vision. Taken together, our results demonstrate that severely degraded acuity and contrast sensitivity may increase people's tendency to overestimate perception of distance traveled, perhaps because of an increased perception of speed of self-motion.

Let me be your guide: physical guidance improves spatial learning for older adults with simulated low vision.

Monitoring one's safety during low vision navigation demands limited attentional resources which may impair spatial learning of the environment. In studies of younger adults, we have shown that these mobility monitoring demands can be alleviated, and spatial learning subsequently improved, via the presence of a physical guide during navigation. The present study extends work with younger adults to an older adult sample with simulated low vision. We test the effect of physical guidance on improving spatial learning as well as general age-related changes in navigation ability. Participants walked with and without a physical guide on novel real-world paths in an indoor environment and pointed to remembered target locations. They completed concurrent measures of cognitive load on the trials. Results demonstrate an improvement in learning under low vision conditions with a guide compared to walking without a guide. However, our measure of cognitive load did not vary between guidance conditions. We also conducted a cross-age comparison and found support for age-related declines in spatial learning generally and greater effects of physical guidance with increasing age.

Effect of Display Technology on Perceived Scale of Space.

OBJECTIVE: Our goal was to evaluate the degree to which display technologies influence the perception of size in an image. BACKGROUND: Research suggests that factors such as whether an image is displayed stereoscopically, whether a user's viewpoint is tracked, and the field of view of a given display can affect users' perception of scale in the displayed image. METHOD: Participants directly estimated the size of a gap by matching the distance between their hands to the gap width and judged their ability to pass unimpeded through the gap in one of five common implementations of three display technologies (two head-mounted displays [HMD] and a back-projection screen). RESULTS: Both measures of gap width were similar for the two HMD conditions and the back projection with stereo and tracking. For the displays without tracking, stereo and monocular conditions differed from each other, with monocular viewing showing underestimation of size. CONCLUSIONS: Display technologies that are capable of stereoscopic display and tracking of the user's viewpoint are beneficial as perceived size does not differ from real-world estimates. Evaluations of different display technologies are necessary as display conditions vary and the availability of different display technologies continues to grow. APPLICATIONS: The findings are important to those using display technologies for research, commercial, and training purposes when it is important for the displayed image to be perceived at an intended scale.

The addition of a spatial auditory cue improves spatial updating in a virtual reality navigation task.

Auditory cues are integrated with vision and body-based self-motion cues for motion perception, balance, and gait, though limited research has evaluated their effectiveness for navigation. Here, we tested whether an auditory cue co-localized with a visual target could improve spatial updating in a virtual reality homing task. Participants navigated a triangular homing task with and without an easily localizable spatial audio signal co-located with the home location. The main outcome was unsigned angular error, defined as the absolute value of the difference between the participant's turning response and the correct response towards the home location. Angular error was significantly reduced in the presence of spatial sound compared to a head-fixed identical auditory signal. Participants' angular error was 22.79° in the presence of spatial audio and 30.09° in its absence. Those with the worst performance in the absence of spatial sound demonstrated the greatest improvement with the added sound cue. These results suggest that auditory cues may benefit navigation, particularly for those who demonstrated the highest level of spatial updating error in the absence of spatial sound.

Perceiving distance in virtual reality: theoretical insights from contemporary technologies.

Decades of research have shown that absolute egocentric distance is underestimated in virtual environments (VEs) when compared with the real world. This finding has implications on the use of VEs for applications that require an accurate sense of absolute scale. Fortunately, this underperception of scale can be attenuated by several factors, making perception more similar to (but still not the same as) that of the real world. Here, we examine these factors as two categories: (i) experience inherent to the observer, and (ii) characteristics inherent to the display technology. We analyse how these factors influence the sources of information for absolute distance perception with the goal of understanding how the scale of virtual spaces is calibrated. We identify six types of cues that change with these approaches, contributing both to a theoretical understanding of depth perception in VEs and a call for future research that can benefit from changing technologies. This article is part of the theme issue 'New approaches to 3D vision'.

New Approaches to 3D Vision.

New approaches to 3D vision are enabling new advances in artificial intelligence and autonomous vehicles, a better understanding of how animals navigate the 3D world, and new insights into human perception in virtual and augmented reality. Whilst traditional approaches to 3D vision in computer vision (SLAM: simultaneous localization and mapping), animal navigation (cognitive maps), and human vision (optimal cue integration) start from the assumption that the aim of 3D vision is to provide an accurate 3D model of the world, the new approaches to 3D vision explored in this issue challenge this assumption. Instead, they investigate the possibility that computer vision, animal navigation, and human vision can rely on partial or distorted models or no model at all. This issue also highlights the implications for artificial intelligence, autonomous vehicles, human perception in virtual and augmented reality, and the treatment of visual disorders, all of which are explored by individual articles. This article is part of a discussion meeting issue 'New approaches to 3D vision'.

The relationship between space and time perception: A registered replication of Casasanto and Boroditsky (2008).

Everything in our environment moves through both space and time, and to effectively act we must be aware of both spatial and temporal elements in relation to our own body. Thus, perception of space and time have an intimate relationship. Walsh's a theory of magnitude (ATOM) suggests that space and time perception rely on a general magnitude system and their relationship should be roughly symmetrical. Alternatively, metaphor theory, which is based on the philosophical work of Lakoff and Johnson, argues that we represent time using spatial metaphor and thus the relationship should be asymmetrical (with space influencing time more than time influences space). A compelling line of evidence for metaphor theory comes from the work of Casasanto and Boroditsky who experimentally demonstrated this asymmetric effect. However, in our previous unpublished online replication attempt of this work, we found a roughly symmetrical relationship between space and time, more in line with the theoretical predictions of ATOM. Given this, we performed a registered replication of Casasanto and Boroditsky (2008) in both an online and laboratory environment.

Evaluating the Visibility of Architectural Features for People with Low Vision -A Quantitative Approach.

Most people with low vision rely on their remaining functional vision for mobility. Our goal is to provide tools to help design architectural spaces in which safe and effective mobility is possible by those with low vision---spaces that we refer to as visually accessible. We describe an approach that starts with a 3D CAD model of a planned space and produces labeled images indicating whether or not structures that are potential mobility hazards are visible at a particular level of low vision. There are two main parts to the analysis. The first, previously described, represents low-vision status by filtering a calibrated luminance image generated from the CAD model and associated lighting and materials information to produce a new image with unseen detail removed. The second part, described in this paper, uses both these filtered images and information about the geometry of the space obtained from the CAD model and related lighting and surface material specifications to produce a quantitative estimate of the likelihood of particular hazards being visible. We provide examples of the workflow required, a discussion of the novelty and implications of the approach, and a short discussion of needed future work.

How can basic research on spatial cognition enhance the visual accessibility of architecture for people with low vision?

People with visual impairment often rely on their residual vision when interacting with their spatial environments. The goal of visual accessibility is to design spaces that allow for safe travel for the large and growing population of people who have uncorrectable vision loss, enabling full participation in modern society. This paper defines the functional challenges in perception and spatial cognition with restricted visual information and reviews a body of empirical work on low vision perception of spaces on both local and global navigational scales. We evaluate how the results of this work can provide insights into the complex problem that architects face in the design of visually accessible spaces.

Visual capture influences body-based indications of visual extent.

Visual information regarding limb location can override proprioceptive information when there is conflict between the two-a phenomenon referred to as visual capture. In three experiments, we employed the "mirror illusion," in which the perceived location of one's hand is influenced by the visual information specified by the mirror reflection of the other hand, to test whether visual capture influences body-based indications of the extent of objects. Participants viewed their visible hand and its reflection in a mirror after the unseen hand was positioned at one of four locations on a tabletop. The unseen hand's location appeared to be the same distance from the mirror as the visible hand's location. After viewing the visible hand and its reflection while simultaneously performing simple finger movements with both hands, participants viewed a block and had to move their unseen hand to a position that would allow them to grasp the block between their two hands. Movements of the unseen hand relative to the visible hand were biased by the visual information, reflecting errors in moved hand position given visual-proprioceptive conflict. In Experiment 1, visual capture influenced the indications of object extent for objects within reach and aligned with the viewer's midline. Experiments 2 and 3 extended these findings to indications of extent for objects outside the viewer's reach (Experiment 2) and misaligned with the viewer's midline (Experiment 3). These results suggest that visual body information has a generalizable effect on actions used to indicate space perception that extends beyond egocentric spatial localization tasks.

The powerful influence of marks: Visual and knowledge-driven processing in hurricane track displays.

Given the widespread use of visualizations to communicate hazard risks, forecast visualizations must be as effective to interpret as possible. However, despite incorporating best practices, visualizations can influence viewer judgments in ways that the designers did not anticipate. Visualization designers should understand the full implications of visualization techniques and seek to develop visualizations that account for the complexities in decision-making. The current study explores the influence of visualizations of uncertainty by examining a case in which ensemble hurricane forecast visualizations produce unintended interpretations. We show that people estimate more damage to a location that is overlapped by a track in an ensemble hurricane forecast visualization compared to a location that does not coincide with a track. We find that this effect can be partially reduced by manipulating the number of hurricane paths displayed, suggesting the importance of visual features of a display on decision making. Providing instructions about the information conveyed in the ensemble display also reduced the effect, but importantly, did not eliminate it. These findings illustrate the powerful influence of marks and their encodings on decision-making with visualizations. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Does active learning benefit spatial memory during navigation with restricted peripheral field?

Spatial learning of real-world environments is impaired with severely restricted peripheral field of view (FOV). In prior research, the effects of restricted FOV on spatial learning have been studied using passive learning paradigms - learners walk along pre-defined paths and are told the location of targets to be remembered. Our research has shown that mobility demands and environmental complexity may contribute to impaired spatial learning with restricted FOV through attentional mechanisms. Here, we examine the role of active navigation, both in locomotion and in target search. First, we compared effects of active versus passive locomotion (walking with a physical guide versus being pushed in a wheelchair) on a task of pointing to remembered targets in participants with simulated 10° FOV. We found similar performance between active and passive locomotion conditions in both simpler (Experiment 1) and more complex (Experiment 2) spatial learning tasks. Experiment 3 required active search for named targets to remember while navigating, using both a mild and a severe FOV restriction. We observed no difference in pointing accuracy between the two FOV restrictions but an increase in attentional demands with severely restricted FOV. Experiment 4 compared active and passive search with severe FOV restriction, within subjects. We found no difference in pointing accuracy, but observed an increase in cognitive load in active versus passive search. Taken together, in the context of navigating with restricted FOV, neither locomotion method nor level of active search affected spatial learning. However, the greater cognitive demands could have counteracted the potential advantage of the active learning conditions.

Toward Objective Evaluation of Working Memory in Visualizations: A Case Study Using Pupillometry and a Dual-Task Paradigm.

Cognitive science has established widely used and validated procedures for evaluating working memory in numerous applied domains, but surprisingly few studies have employed these methodologies to assess claims about the impacts of visualizations on working memory. The lack of information visualization research that uses validated procedures for measuring working memory may be due, in part, to the absence of cross-domain methodological guidance tailored explicitly to the unique needs of visualization research. This paper presents a set of clear, practical, and empirically validated methods for evaluating working memory during visualization tasks and provides readers with guidance in selecting an appropriate working memory evaluation paradigm. As a case study, we illustrate multiple methods for evaluating working memory in a visual-spatial aggregation task with geospatial data. The results show that the use of dual-task experimental designs (simultaneous performance of several tasks compared to single-task performance) and pupil dilation can reveal working memory demands associated with task difficulty and dual-tasking. In a dual-task experimental design, measures of task completion times and pupillometry revealed the working memory demands associated with both task difficulty and dual-tasking. Pupillometry demonstrated that participants' pupils were significantly larger when they were completing a more difficult task and when multitasking. We propose that researchers interested in the relative differences in working memory between visualizations should consider a converging methods approach, where physiological measures and behavioral measures of working memory are employed to generate a rich evaluation of visualization effort.

Sensory-motor and cognitive functions of the human posterior parietal cortex involved in manual actions.

The posterior parietal cortex (PPC) is considered the dominant structure in the dorsal stream of visual processing, defined in the context of systems for perception and action. It is well-established that the human PPC is critical to sensory-motor transformations involved in online manual actions. A related body of literature identifies the PPC as important to cognitive aspects of action representation such as imagery, tool use, and gestures. The goal of the present paper is to review and compare the PPC contribution to representations of both motor control and motor cognition. Relating the sensory-motor and cognitive components of PPC function is important for an understanding of integrative representations of manual actions and the relation between perception, action, and cognition. Proposed theories of multiple dorsal stream systems supporting different action-relevant goals are discussed.

Navigating with peripheral field loss in a museum: learning impairments due to environmental complexity.

BACKGROUND: Previous research has found that spatial learning while navigating in novel spaces is impaired with extreme restricted peripheral field of view (FOV) (remaining FOV of 4°, but not of 10°) in an indoor environment with long hallways and mostly orthogonal turns. Here we tested effects of restricted peripheral field on a similar real-world spatial learning task in an art museum, a more challenging environment for navigation because of valuable obstacles and unpredictable paths, in which participants were guided along paths through the museum and learned the locations of pieces of art. At the end of each path, participants pointed to the remembered landmarks. Throughout the spatial learning task, participants completed a concurrent auditory reaction time task to measure cognitive load. RESULTS: Unlike the previous study in a typical hallway environment, spatial learning was impaired with a simulated 10° FOV compared to a wider 60° FOV, as indicated by greater average pointing error with restricted FOV. Reaction time to the secondary task also revealed slower responses, suggesting increased attentional demands. CONCLUSIONS: We suggest that the presence of a spatial learning deficit in the current experiment with this level of FOV restriction is due to the complex and unpredictable paths traveled in the museum environment. Our results also convey the importance of the study of low-vision spatial cognition in irregularly structured environments that are representative of many real-world settings, which may increase the difficulty of spatial learning while navigating.

Mind the Gap: Gap Affordance Judgments of Children, Teens, and Adults in an Immersive Virtual Environment.

Affordances are possibilities for action that depend on both an observer's capabilities and the properties of the environment. Immersive Virtual Environments (IVEs) have been used to examine affordances in adults, demonstrating that judgments about action capabilities are made similarly to the real world. However, less is known about affordance judgments in middle-aged children and adolescents in IVEs. Differences in rate of growth, decision criteria, and perceived risk could influence affordance judgments for children. In Experiment 1, children, teens, and adults stood in an IVE at ground level or at a height of 15 m, and were asked to view gaps of different widths. Across all age groups, estimates of gap crossing were underestimated at the higher height compared to the ground, consistent with reports of fear and risk of falling. Children, compared to adults, underestimated their maximum crossable gap compared to their actual crossable gap. To test whether this difference was specific to IVEs or a more generalized age effect, children and adults were tested on gap estimates in the real world in Experiment 2. This real world study showed no difference between children and adults, suggesting a unique contribution of the IVE to children's affordance judgments. We discuss the implications for using IVEs to study children's affordances.