Angular Disparity Research Articles

The cost of perspective switching: Constraints on simultaneous activation.

Visual perspective taking often involves transitioning between perspectives, yet the cognitive mechanisms underlying this process remain unclear. The current study draws on insights from task- and language-switching research to address this gap. In Experiment 1, 79 participants judged the perspective of an avatar positioned in various locations, observing either the rectangular or the square side of a rectangular cube hanging from the ceiling. The avatar's perspective was either consistent or inconsistent with the participant's, and its computation sometimes required mental transformation. The task included both single-position blocks, in which the avatar's location remained fixed across all trials, and mixed-position blocks, in which the avatar's position changed across trials. Performance was compared across trial types and positions. In Experiment 2, 126 participants completed a similar task administered online, with more trials, and performance was compared at various points within the response time distribution (vincentile analysis). Results revealed a robust switching cost. However, mixing costs, which reflect the ability to maintain multiple task sets active in working memory, were absent, even in slower response times. Additionally, responses to the avatar's position varied as a function of consistency with the participants' viewpoint and the angular disparity between them. These findings suggest that perspective switching is costly, people cannot activate multiple perspectives simultaneously, and the computation of other people's visual perspectives varies with cognitive demands.

Assessment of embodied visuospatial perspective taking in augmented reality: insights from a reaction time task

Understanding another person’s visual perceptions is known as visuospatial perspective taking, with evidence to date demonstrating it is delineated across two levels, depending on how different that perspective is. Some strategies for visuospatial perspective taking have also been found to involve embodied cognition. However, the current generalisation of these findings is limited due to experimental setup and the use of computer monitors as the interface for experimental tasks. Augmented reality interfaces could possibly extend on the generalisation of these findings by situating virtual stimuli in the real environment, thus providing a higher degree of ecological validity and experimental standardisation. This study aimed to observe visuospatial perspective taking in augmented reality. This was achieved in participant experiments (N=24) using the Left-Right behavioural speeded decision task, which requires participants to discriminate between target objects relative to the perspective of an avatar. Angular disparity and posture congruence between the avatar and participant were manipulated between each trial to delineate between the two levels of visuospatial perspective taking and understand its potentially embodied nature. Although generalised linear mixed modeling indicated that angular disparity increased task difficulty, unexpectedly findings on posture congruence were less clear. Together, this suggests that visuospatial perspective taking in this study can be delineated across two levels. Further implications for embodied cognition and empathy research are discussed.

Spatial Perspective Taking in Non-Autistic Children and Autistic Children: Do Social Processes Benefit or Obstruct?

ABSTRACT The present study investigated whether the presence of another person in a visuospatial perspective taking (VSPT) paradigm would influence the performance of non-autistic and autistic children. Experiment 1 tested non-autistic children aged 5–7 (N = 82, 42 girls) in a self-condition (pure spatial updating of self-mental rotation) and an other-condition (taking another agent’s perspective). Experiment 2 compared 18 autistic children (3 girls, aged 7.17–14.33 years old) and 22 mental ability-matched non-autistic peers (10 girls, M age = 6.82). Both experiments were conducted in mainland China with Chinese participants. Non-autistic children below 7 years of age and autistic children performed better in the self-condition than in the other-condition, especially when angular disparities were greater than 90°, while no such differences were observed in 7-year-old non-autistic children. The interaction between perspective and angular disparity indicated the interference of another agent’s presence in typical VSPT tasks from a developmental perspective. The results were discussed with regard to the nonsynchronous development of spatial and social ability involved in the VSPT paradigm and its implications for the purity of VSPT as a measure of spatial ability.

The effect of internal and external visualization of rotation on postural stability

IntroductionDuring mental rotation tasks, it is assumed that participants visualize a rotation of objects in their minds (internal visualization), but mental rotation has also been linked to the visible rotation of objects on a screen (external visualization). The angular disparity in mental rotation also influences postural sway, the movements of the body center. Postural sway is thus suspected as one type of indirect measurement of the rotation process. We compare the external visualization of rotation with the suspected internal visualization during mental rotation tasks. We suspect both are similar and thus produce a comparable effect on postural sway.MethodsOne hundred and fifty participants completed three rotation tasks with cube figures, two of which were aided by external visualization. Their center of pressure was measured throughout. The effects of external visualization, angular disparity, and their interaction on postural sway were compared using Bayesian statistics and a decision boundary of 3 or 1/3.Results and discussionThe results indicate no differences between conditions for all postural sway parameters. We observe differences between conditions in cognitive load and reaction time. However, as these partially also differ between the two external visualization conditions and do not transfer to differences between the postural sway parameters, the underlying processes in the three conditions are likely similar. Our results support the notion that the visualization of rotation is central to postural sway during mental rotation. This further supports that the rotation process of the external visualization and mental rotation are similar and thus that stimuli are indeed rotated mentally during mental rotation tasks. Our results further support that the common process between mental and manual rotation lies in the visualization instead of mental rotation being an imagined motor action. Because visual control and feedback play an essential role in many motor tasks, the results could also be of further interest for a more general link between motor and cognitive tasks and bidirectional benefits through the construction of visual similarities.

Three-Dimensional Mapping of the Rotation of Interactive Virtual Objects with Eye-Tracking Data.

We present a method for real-time recording of human interaction with three-dimensional (3D) virtual objects. The approach consists of associating rotation data of the manipulated object with behavioral measures, such as eye tracking, to make better inferences about the underlying cognitive processes. The task consists of displaying two identical models of the same 3D object (a molecule), presented on a computer screen: a rotating, interactive object (iObj) and a static, target object (tObj). Participants must rotate iObj using the mouse until they consider its orientation to be identical to that of tObj. The computer tracks all interaction data in real time. The participant's gaze data are also recorded using an eye tracker. The measurement frequency is 10 Hz on the computer and 60 Hz on the eye tracker. The orientation data of iObj with respect to tObj are recorded in rotation quaternions. The gaze data are synchronized to the orientation of iObj and referenced using this same system. This method enables us to obtain the following visualizations of the human interaction process with iObj and tObj: (1) angular disparity synchronized with other time-dependent data; (2) 3D rotation trajectory inside what we decided to call a "ball of rotations"; (3) 3D fixation heatmap. All steps of the protocol have used free software, such as GNU Octave and Jmol, and all scripts are available as supplementary material. With this approach, we can conduct detailed quantitative studies of the task-solving process involving mental or physical rotations, rather than only the outcome reached. It is possible to measure precisely how important each part of the 3D models is for the participant in solving tasks, and thus relate the models to relevant variables such as the characteristics of the objects, cognitive abilities of the individuals, and the characteristics of human-machine interface.

Visual perspective taking and action understanding

Understanding what others are doing is a fundamental aspect of social cognition and a skill that is arguably linked to visuospatial perspective taking (VPT), the ability to apprehend the spatial layout of a scene from another's perspective. Yet, with few and notable exceptions, action understanding and VPT are rarely studied together. Participants (43 females, 37 males) made judgements about the spatial layout of objects in a scene from the perspective of an avatar who was positioned at 0°, 90°, 270° or 180° relative to the participant. In a variant of a traditional VPT task, the avatar either interacted with the objects in the scene, by pointing to or reaching for them, or was present but did not engage with the objects. Although the task was identical across all conditions - to say whether a target object is to the right or left of a control object - we show that the avatar's actions modulates performance. Specifically, participants were more accurate when the avatar engaged with the target object, and correspondingly, less accurate and slower when the avatar interacted with the control objects. As these effects were independent of the angular disparity between participant and avatar perspectives, we conclude that action understanding and VPT are likely linked via the rapid deployment of two separate cognitive mechanisms. All participants provided a measure of self-reported empathy and we show that response times decrease with increasing empathy scores for female but not for male participants. However, within the range of ‘typical’ empathy scores, defined here as the interquartile range where 50 % of the data lie, females were faster than males. These findings lend further insight into the relationship between spatial and social perspective taking.

Phase-Field Simulation of Grain Growth in Uranium Silicide Nuclear Fuel

Uranium silicide (U3Si2) is regarded as a viable fuel option for improving the safety of nuclear power plants. In the present work, phase-field simulations were employed to investigate grain growth phenomena, encompassing both isotropic and anisotropic grain growth. In simulations of isotropic grain growth, it is commonly assumed that the energy and mobility of the grain boundaries (GBs) remain constant, represented by average values. The calculated grain growth kinetic rate constant, K, exhibits a close correspondence with the experimental measurements, indicating a strong agreement between the two. In simulations of anisotropic grain growth, the values of GB energy and mobility are correlated with the angular disparity between GBs. The simulation results demonstrated that the growth rate of U3Si2 can be influenced by both the energy anisotropy and mobility anisotropy of GBs. Furthermore, the anisotropy in mobility results in a greater prevalence of low-angle GB distribution in comparison to high-angle GBs. However, the energy anisotropy of GBs does not impact the frequency distribution of the angle difference between GBs.

Features and strategy influence performance on a chemistry spatial task

Spatial thinking is an important skill for success in the chemistry classroom. Experimental studies on mental rotation, a key skill for spatial thinking, show interesting trends in participant performance on 2D and 3D similarity judgement tasks. In these studies, participants’ use of mental rotation is determined by linear regression and/or correlations of response time versus angular disparity of the task. While judgements with block diagrams are amenable to mental rotation, studies find differences with the more symbolic 2D chemistry diagrams depending in the participants’ expertise: novices tend to use mental rotation, while experts use algorithms or other heuristics. Herein, we study these aspects chemistry, spatial thinking, and mental rotation, adding to prior work by investigating the effect of time limits and how task variables like axis and angular disparity influence task performance. We also incorporated a block design that allowed us to look for practice effects. This study was conducted online with undergraduate students ( N = 162) and designed as a conceptual replication of Stieff et al. (2018) to explore how features of the task (e.g., axis of rotation) influence participants accuracy, response time, and their use of mental rotation, diagrammatic, analytic, or algorithmic strategies. Our results suggest that mental rotation was being used successfully for only z-axis rotations, with other strategies such as symmetry heuristics are likely being used for x- and y-axis rotations. We also found that practice can improve stereochemistry task performance. These findings support chemistry novices’ reliance on mental rotation but also suggest that alternative strategies are used when time is limited.

A New Procedure and Stimulus Set for Examining Cross-Modality Mental Rotation

We validated the use of 3-D printed Shepard and Metzler-style shapes in a simultaneous cross-modal (vision & touch) mental rotation procedure. Participants compared a visually presented 3-D shape to a 3-D shape they could only feel to determine if the shapes were the same. Participant response time and error rate demonstrated the expected linear increase as the angular disparity of the 3-D printed shapes increased. We expect the freely available data and stimuli from the procedure will be useful to researchers studying both traditional mental rotation and cross-modality mental rotation with complex, highly adaptable, and easy to create shapes.

Slower but more accurate mental rotation performance in aphantasia linked to differences in cognitive strategies

Mental rotation tasks are frequently used as standard measures of mental imagery. However, aphantasia research has brought such use into question. Here, we assessed a large group of individuals who lack visual imagery (aphantasia) on two mental rotation tasks: a three-dimensional block-shape, and a human manikin rotation task. In both tasks, those with aphantasia had slower, but more accurate responses than controls. Both groups demonstrated classic linear increases in response time and error-rate as functions of angular disparity. In the three-dimensional block-shape rotation task, a within-group speed-accuracy trade-off was found in controls, whereas faster individuals in the aphantasia group were also more accurate. Control participants generally favoured using object-based mental rotation strategies, whereas those with aphantasia favoured analytic strategies. These results suggest that visual imagery is not crucial for successful performance in classical mental rotation tasks, as alternative strategies can be effectively utilised in the absence of holistic mental representations.

The influence of another’s actions and presence on perspective taking

The ability to take each other’s visuospatial perspective has been linked to people’s capacity to perceive another’s action possibilities and to predict their actions. Research has also shown that visuospatial perspective taking is supported by one’s own mental own-body transformation. However, how these two processes of action perception and visuospatial perspective taking might interact remains largely unknown. By introducing seven angular disparities between participants and the model in the stimuli pictures across “Action” and “No Action” conditions, we investigated whether the observation of a goal-directed action facilitates perspective taking and whether this facilitation depends on the level of mental own-body transformation required to take perspective. The results showed that action observation facilitated performance independently of the level of mental-own body transformation. The processes behind this facilitation could involve anatomical mapping that is independent of the congruency between the participants’ and the model’s perspectives. Further, we replicated previous research findings, showing that participants were more accurate and faster when taking the perspective of a person compared to an inanimate object (a chair). The strongest facilitation effects were seen at the highest angular disparities between participants and the model in the stimuli pictures. Together, these findings enhance our knowledge of the mechanisms behind visuospatial perspective taking.

Radargrammetric 3D Imaging through Composite Registration Method Using Multi-Aspect Synthetic Aperture Radar Imagery

Interferometric synthetic aperture radar (InSAR) and tomographic SAR measurement techniques are commonly used for the three-dimensional (3D) reconstruction of complex areas, while the effectiveness of these methods relies on the interferometric coherence among SAR images with minimal angular disparities. Radargrammetry exploits stereo image matching to determine the spatial coordinates of corresponding points in two SAR images and acquire their 3D properties. The performance of the image matching process directly impacts the quality of the resulting digital surface model (DSM). However, the presence of speckle noise, along with dissimilar geometric and radiometric distortions, poses considerable challenges in achieving accurate stereo SAR image matching. To address these aforementioned challenges, this paper proposes a radargrammetric method based on the composite registration of multi-aspect SAR images. The proposed method combines coarse registration using scale invariant feature transform (SIFT) with precise registration using normalized cross-correlation (NCC) to achieve accurate registration between multi-aspect SAR images with large disparities. Furthermore, the multi-aspect 3D point clouds are merged using the proposed radargrammetric 3D imaging method, resulting in the 3D imaging of target scenes based on multi-aspect SAR images. For validation purposes, this paper presents a comprehensive 3D reconstruction of the Five-hundred-meter Aperture Spherical radio Telescope (FAST) using Ka-band airborne SAR images. It does not necessitate prior knowledge of the target and is applicable to the detailed 3D imaging of large-scale areas with complex structures. In comparison to other SAR 3D imaging techniques, it reduces the requirements for orbit control and radar system parameters. To sum up, the proposed 3D imaging method with composite registration guarantees imaging efficiency, while enhancing the imaging accuracy of crucial areas with limited data.

Agent-Object Relationships in Level-2 Visual Perspective Taking: An Eye-Tracking Study.

Visual perspective taking (VPT) generates a shared frame of reference for understanding how the world appears to others. Whilst greater cognitive and neurophysiological demands are associated with increasing angular distance between the self and other is well documented, accompanying attentional characteristics are not currently understood. Furthermore, although age and group status have been shown to impact task performance, other important cues, such as the relationship between agents and objects, have not been manipulated. Therefore, 35 university students participated in an eye-tracking experiment where they completed a VPT task with agents positioned at a low or high angular disparity (45° or 135° respectively). The congruence between the age of the agent (child vs adult) and the object they are attending to (e.g., teddy-bear vs kettle) was also manipulated. Participants were required to respond to the direction of the object from the agent's position. The findings reveal more fixations and increased dwell-times on agents compared to objects, but this was moderated by the age of the task agent. Results also showed more attentional transitions between agents and objects at higher angular disparities. These results converge with behavioural and neurophysiological descriptions of task performance in previous studies. Furthermore, the congruency of the relationship between agents and objects also impacted attention shifting and response times, highlighting the importance of understanding how social cues and contexts can modulate VPT processes in everyday contexts and social interaction.

The effect of angular disparity between sound source sequences on the perceptual organization of auditory objects

Within auditory scene analysis is a well-known streaming phenomenon which is observed when listeners group several sounds into “auditory objects” in complex auditory scenes. When two auditory sequences consist of similar sounds, these sequences tend to be perceived as a single stream, but can form segregated streams when the sounds are presented from disparate angles. This study investigated the tolerance thresholds for the angular disparity at which the sound sources would segregate rather than group together into single auditory objects, when 50-ms one-third octave bands of noise were presented in the horizontal plane with changing azimuth angle. Listeners were asked to judge whether the presented noise sequences were perceived as a single stream or not. The results revealed that listeners tend to perceive the presented sequences as a single stream when the angular disparity between noises was small; however, these tolerance thresholds depended on the spatial region within which the sequences were presented. Tolerance thresholds became large when the noise sequences were presented from the side, in comparison to the situation when sequences were presented from in front of the listeners. Results were consistent with the minimum audible angle on the horizontal plane.

Eye movement characteristics in a mental rotation task presented in virtual reality.

Eye-tracking technology provides a reliable and cost-effective approach to characterize mental representation according to specific patterns. Mental rotation tasks, referring to the mental representation and transformation of visual information, have been widely used to examine visuospatial ability. In these tasks, participants visually perceive three-dimensional (3D) objects and mentally rotate them until they identify whether the paired objects are identical or mirrored. In most studies, 3D objects are presented using two-dimensional (2D) images on a computer screen. Currently, visual neuroscience tends to investigate visual behavior responding to naturalistic stimuli rather than image stimuli. Virtual reality (VR) is an emerging technology used to provide naturalistic stimuli, allowing the investigation of behavioral features in an immersive environment similar to the real world. However, mental rotation tasks using 3D objects in immersive VR have been rarely reported. Here, we designed a VR mental rotation task using 3D stimuli presented in a head-mounted display (HMD). An eye tracker incorporated into the HMD was used to examine eye movement characteristics during the task synchronically. The stimuli were virtual paired objects oriented at specific angular disparities (0, 60, 120, and 180°). We recruited thirty-three participants who were required to determine whether the paired 3D objects were identical or mirrored. Behavioral results demonstrated that the response times when comparing mirrored objects were longer than identical objects. Eye-movement results showed that the percent fixation time, the number of within-object fixations, and the number of saccades for the mirrored objects were significantly lower than that for the identical objects, providing further explanations for the behavioral results. In the present work, we examined behavioral and eye movement characteristics during a VR mental rotation task using 3D stimuli. Significant differences were observed in response times and eye movement metrics between identical and mirrored objects. The eye movement data provided further explanation for the behavioral results in the VR mental rotation task.

Is this a real 3D shape? An investigation of construct validity and item difficulty in the PSVT:R

ABSTRACTThe Purdue Test of Spatial Visualization (PSVT:R) is a widely used measure of spatial ability. Though the PSVT:R is considered to be a mental rotation test, degree of angular disparity between shapes does not correspond with degree of item difficulty. In the present study, we investigate the possibility that drawings that do not naturally look like 3D shapes could affect item difficulty in the Revised PSVT:R. We conducted a shape sorting task in which participants (N = 588) were asked whether shapes from the Revised PSVT:R looked like real 3D solid shapes or not. We also made a modified version of the Revised PSVT:R in which we changed which answer was correct and compared with performance on the Revised PSVT:R (N = 807). Some questions that should have been easier based on the degree of rotation instead became harder. Our results suggest that some of the isometric drawings in the PSVT:R may not clearly look like 3D shapes and that this fact may explain why item difficulty does not correspond to degree of rotation. Our findings raise questions about whether the PSVT:R can be considered to measure mental rotation as traditionally understood.

Manipulating avatar age and gender in level-2 visual perspective taking

Visual perspective taking (VPT) represents how the world appears from another person’s position. The age, group status and emotional displays of the other person have been shown to affect task performance, but tasks often confound social and spatial outcome measures by embedding perspective taking in explicitly social contexts or theory-of-mind reasoning. Furthermore, while previous research has suggested that visual perspective taking may be impacted by avatar characteristics, it is unknown whether this is driven by general group processing or a specific deficit in mentalizing about outgroups, for example, children. Therefore, using a minimally social task (i.e., the task was not communicative, and acknowledging the “mind” of the avatar was not necessitated), we examined whether avatar age and avatar gender affect performance on simpler (low angular disparity) and more effortful, embodied (high angular disparity) perspective judgments. Ninety-two participants represented the visuospatial perspectives of a boy, girl, man, or woman who were presented at various angular disparities. A target object was placed in front of the avatar and participants responded to the orientation of the object from the avatar’s position. The findings suggest that social features of visuospatial perspective taking (VSPT) are processed separately from the fundamental spatial computations. Further, Level-2 VSPT appears to be affected by general group categorization (e.g., age and gender) rather than a deficit in mentalizing about a specific outgroup (e.g., children).

The spatial requirements of the left-hand rule: a novel instrument for assessing the coordination of egocentric and allocentric frames of reference

ABSTRACT This paper explores the spatial dimension of Fleming’s Left Hand Rule (LHR), commonly-used in Physics instruction for determining the direction of force using the left hand’s thumb, forefinger and middle finger. A new instrument was developed to gauge students’ ability to coordinate their fingers in 3D space (egocentric frame of reference) based on representations of tasks on paper/screen (allocentric frame of reference). The LHR scores from a sample of 530 Grade 10 and 11 students revealed a significant correlation to standard spatial reasoning measures, with a reliability of 0.77. About 90% of the students scored less than 10 points out of 22, highlighting the relevance of the spatial skills required for articulating the LHR. Science students performed significantly better than non-Science students. The manipulation of the LHR was strongly influenced by the degree of angular disparity between the body frame and task-defined frame and the kinaesthetic constraints required to rotate the triad of fingers as a perpendicular frame.

A comparative analysis of dual-axis implants placed into maxillary anterior extraction sockets versus virtual planning with uniaxial implants: A simulated cone beam computed tomography study of implant length and diameter.

The biaxial nature of the anterior maxilla poses a surgical and restorative challenge in implant dentistry. The present study sought to investigate the apical socket perforation rate (ASPR) from a simulated uniaxial implant placement and to determine the effect of implant length and diameter on ASPR when a uniaxial implant was placed compared with the orientation of the pre-existing dual-axis implant. Cone beam computed tomography (CBCT) scans from the database of three private practices were searched for patients who received dual-axis implants within the esthetic zone in immediate tooth replacement therapy. A uniaxial implant was virtually placed using the pre-existing screw access channel of the dual-axis implant as a reference. The closest length and diameter were selected for the simulated implant. ASPR by the uniaxial implant was recorded. In addition, the affordable maximum length of a corresponding uniaxial implant that would avoid apical socket perforation was measured. Eighty-one patients with a total of 101 dual-axis dental implants were selected for analysis. A simulated virtual surgical planning with uniaxial implants revealed high ASPR (48.51%). When the length of the uniaxial implant was reduced to 11 and 9 mm, ASPR was decreased to 41.58% and 20.79%, respectively. Dual-axis implant design effectively evades anatomical challenges in the anterior maxilla (esthetic zone). Considering the current evidence, efforts should be made to carefully consider the angular disparity between the extraction socket-alveolus complex and the future restorative emergence so that a harmonious biologic-esthetic result may be more predictably and consistently obtained.

Training effect on sex-based differences in components of the Shepard and Metzler mental rotation task

BackgroundSpatial ability has been reported to indicate sex-based differences in humans, mainly assessed by Shepard and Metzler mental rotation task (SM-MRT). Most performances in earlier studies have been evaluated by the mean value of reaction time and/or accuracy. The performance indexes might not be sensitive measures of mental rotation. Sex-based differences in the performance might also be involved in the spatial experience of the subject at the time. This study observed variations in components of the SM-MRT over repetition.MethodsMale (n = 17) and female (n = 17) subjects completed 20 days of repeating the SM-MRT. The slope and intercept of the function performance (reaction time) to the angular disparity are calculated; the slope of this function indexes the mental rotation (main-process), and the intercept indexes the other sub-processes.ResultsA significant main effect of sex was obtained on the slope. The intercept also showed a tendency toward statistical difference. The interactions between the sexes and the day were not significant for the indices. Statistical testing for coefficient of variations (CV) indicated no sex-based difference in the effect of the intercept throughout the experiment day. The CV of the slope, however, showed tendencies toward sex-based difference from days 7 to 12.ConclusionsThe difference between the sexes in performance on the slope was sustained throughout the experimental period. A few female subjects who demonstrated larger slope values than male subjects caused the sex difference. The learning rate of mental rotation may be an inherent spatial ability.