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Ball trajectories validation. With-in shot comparison between real cue ball trajectory (measured with a highspeed camera) and the virtual ball trajectory (calculated by the VR physics engine). Each one is a shot. A total of 100 billiard shots at various directions (-50˚< ø < 50˚when50˚when 0 is straight forward) are presented. (A) Cue ball angles. (B) Max velocity of the cue ball during each trial. The regression line is in black with its 95% CI in doted lines. Identity line is in light gray. https://doi.org/10.1371/journal.pone.0245717.g002
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Motor-learning literature focuses on simple laboratory-tasks due to their controlled manner and the ease to apply manipulations to induce learning and adaptation. Recently, we introduced a billiards paradigm and demonstrated the feasibility of real-world-neuroscience using wearables for naturalistic full-body motion-tracking and mobile-brain-imagin...
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Context 1
... cue ball angles were perfectly correlated (Pearson correlation r = 0.99) and the root mean squared error (RMSE) was below 3 degrees (RMSE = 2.85). Thus, the angle of the virtual ball in the EVR, which defines the performance in this billiards task, was very consistent with the angle of the real-world ball (Fig 2A). The velocities were also highly correlated (Pearson correlation r = 0.83) between the environments but the ball velocities in the VR were slightly slower than on the real pool-table (Fig 2B), leading to an RMSE of 1.03 m/s. ...
Context 2
... the angle of the virtual ball in the EVR, which defines the performance in this billiards task, was very consistent with the angle of the real-world ball (Fig 2A). The velocities were also highly correlated (Pearson correlation r = 0.83) between the environments but the ball velocities in the VR were slightly slower than on the real pool-table (Fig 2B), leading to an RMSE of 1.03 m/s. ...
Citations
... To overcome this limitation, we integrated our billiards task into an Embodied Virtual Reality setup. This setup allows for visual manipulations without compromising the complex movements required by a real-world task (Haar et al., 2021). The Embodied Virtual Reality (EVR) setup synchronises a physical pool table, cue stick, and balls with a virtual environment using optical markerbased motion capture technology. ...
... This embodiment enables participants to physically interact with real-world objects, experiencing complete somatosensory and proprioceptive feedback. Haptic feedback is maintained as participants shoot a physical cue ball along with realistic collision sounds; however, artificial sounds represent collisions between the cue ball and target balls that are solely virtual but programmed to adhere to real physics similar to other objects in the virtual environment (for validation see Haar et al., 2021). Pre-experiment calibration via four cameras and VR controllers ensures alignment between dimensions of virtual and real tables for enhanced realism. ...
This study examines the distinctiveness of error-based and reward-based mechanisms in motor learning, which are traditionally isolated in laboratory tasks but co-occur in real-world scenarios. Using Embodied Virtual Reality (EVR) of pool billiards - allowing for full proprioception via interaction with the physical pool table, cue stick, and balls - we introduced visual perturbations to a real-world task. Participants underwent sessions learning a visual rotation with either error or reward feedback. While participants corrected the entire rotation with error feedback, only partial correction was observed with reward feedback, highlighting the influence of the feedback regime. However, lag-1 autocorrelation and inter-trial variability decay, indicators of skill learning, showed no significant differences between sessions, suggesting that the provided visual feedback did not exclusively engage specific learning mechanisms. Analysis of post-movement beta rebound (PMBR), a marker of brain activity associated with learning mechanisms, revealed a decrease in PMBR with reward feedback but no consistent trend during error feedback sessions. These findings suggest that while reward feedback was absent in error conditions, participants still engaged in reward-based learning, indicating that feedback manipulation alone may not sufficiently challenge individual learning mechanisms in real-world settings. This study underscores the complexity of motor learning processes and highlights that visual feedback by itself can not elucidate the interplay between error-based and reward-based mechanisms in real-world contexts.
... Among the collected studies, fourteen studies used a within-subject experimental design [25][26][27][28][29][30][31][32][33][34][35][36][37][38], whereas one study used a between-subjects experimental design [39]. ...
... Thirteen studies reported behavioral outcomes [26][27][28][29][30][31][32][33][35][36][37][38][39], whereas two studies also included results on psychophysiological correlates [25,34]. ...
... Regarding the type of agency, five studies investigated implicit agency [25,[27][28][29]31], whereas the other ten investigated a mixed sense of agency (implicit and explicit) [25,26,30,[32][33][34][36][37][38][39]. ...
Agency is central to remote actions, and it may enhance skills learning due to a partial overlap between brain structures and networks, the promotion of confidence towards a telemanipulator, and the feeling of congruence of the motor choice to the motor plan. We systematically reviewed studies aiming to verify the role of agency in improving learning. Fifteen studies were selected from MEDLINE and Scopus ®. When a mismatch is introduced between observed and performed actions, the decrease in agency and learning is proportional to the intensity of the mismatch, which is due to greater interference with the motor programming. Thanks to multisensory integration, agency and learning benefit both from sensory and performance feedback and from the timing of feedback based on control at the goal level or the perceptual-motor level. This work constitutes a bedrock for professional teleoperation settings (e.g., robotic surgery), with particular reference to the role of agency in performing complex tasks with remote control.
... Oliver and Hollis (2021) conducted a feasibility study on the influence of the eating environment on eating behavior using VR, indicating the potential of VR as a tool for studying environmental influences on behavior. Haar et al. (2021) utilized embodied VR for the study of real-world motor learning, demonstrating the application of VR in studying sensory-motor interactions and learning. Furthermore, Picket & Dando (2019) provided evidence of the influence of environmental immersion on hedonics, perceived appropriateness, and willingness to pay in alcoholic beverages, highlighting the impact of context, including VR, on sensory testing. ...
Sensory analysis is crucial for optimizing experiences in various fields, including food, cosmetics, and product design. Traditional methods can be inefficient and imprecise. This study introduces a novel approach by blending Virtual Reality (VR) technology with scent identification techniques. The aim is to investigate whether the visual representation of food products affects scent perception. Limited research has explored the use of VR in scent identification, which is especially relevant when altering the food environment setting. A virtual sensory laboratory was developed to mimic MATE's sensory booth. Sixty participants, all MATE students, were involved in this study. This method offers a potential means to streamline scent identification and reduce human bias in sensory analysis. In summary, the combination of VR technology and scent identification presents a fresh methodological approach to sensory analysis, where both scent and exposure are influenced by the environment or imagery. This concept delves into cross-modal correspondences and the role of sensory cues in shaping our perception of food odours within the VR setting.
... Unlike traditional VR, which involves sitting or standing and using handheld controllers to interact with virtual objects, EVR requires whole-body movements that closely simulate realworld actions. This feature can be particularly useful for individuals with motor impairments, as it allows them to practice and improve their motor skills in a safe and controlled environment, favouring generalisability [14], [21]. ...
... In order to pursue the objectives described above, in the past few years we established a billiard task as a valid and engaging way to study motor learning [26], [27] and created Bill-EVR, an innovative Embodied Virtual Reality setup [21]. It filled the gaps of the real-world task limitations while preserving the possibilities of introducing manipulations and customising the environment, and maintaining the subjects' sense of embodiment. ...
... This section provides a detailed account of the EVR experimental setup, extended from [21], the experimental design, participant selection, and data collection and analysis. ...
VR rehabilitation is an established field by now, however, it often refers to computer screen-based interactive rehabilitation activities. In recent years, there was an increased use of VR-headsets, which can provide an immersive virtual environment for real-world tasks, but they are lacking any physical interaction with the task objects and any proprioceptive feedback. Here, we focus on Embodied Virtual Reality (EVR), an emerging field where not only the visual input via VR-headset but also the haptic feedback is physically correct. This happens because subjects interact with physical objects that are veridically aligned in Virtual Reality. This technology lets us manipulate motor performance and motor learning through visual feedback perturbations. Bill-EVR is a framework that allows interventions in the performance of real-world tasks, such as playing pool billiard, engaging end-users in motivating life-like situations to trigger motor (re)learning - subjects see in VR and handle the real-world cue stick, the pool table and shoot physical balls. Specifically, we developed our platform to isolate and evaluate different mechanisms of motor learning to investigate its two main components, error-based and reward-based motor adaptation. This understanding can provide insights for improvements in neurorehabilitation: indeed, reward-based mechanisms are putatively impaired by degradation of the dopaminergic system, such as in Parkinson's disease, while error-based mechanisms are essential for recovering from stroke-induced movement errors. Due to its fully customisable features, our EVR framework can be used to facilitate the improvement of several conditions, providing a valid extension of VR-based implementations and constituting a motor learning tool that can be completely tailored to the individual needs of patients.
... Furthermore, a posttest that is a minimum of 24 hr between the acquisition phase and the posttest (i.e., retention) is important to determine the permanence of observed behavioral changes (Gray, 2019;Schmidt et al., 2019). Many previous studies have investigated the effects of immersive VR on motor performance (Anglin et al., 2017;Cochran et al., 2021;Haar et al., 2021;Harris et al., 2020;Michalski, Szpak, Saredakis et al., 2019;Oagaz et al., 2021). However, the number of studies that fit the previously mentioned transfer of learning criteria is minimal. ...
Previous research has shown practice within an immersive virtual reality (VR) environment improves performance in a physical environment. Increased user motivation is one possible advantage of practicing in VR. One recent study showed that an enriched gaming environment led to higher levels of engagement, resulting
in a direct learning benefit. The purpose of this study was to compare the intrinsic motivation, engagement, and transfer of learning between VR practice and physical practice of the same motor skill. Participants (n = 61) were randomly assigned to a
physical (n = 30) or a VR practice group (n = 31) in which they performed a golf putting task. Analyses showed VR practice led to a significantly greater increase in average intrinsic motivation inventory score than physical practice. Analyses for performance showed there was a significant (p < .001) improvement in accuracy (i.e., radial error) from pre- to posttest, but the two groups did not differ. Overall, these results partially support our hypotheses suggesting that VR practice led to a greater increase in motivation compared with physical practice. Additionally, these results suggest that VR practice was similarly effective at improving accuracy compared with physical practice. Future research directions are discussed.
... These technologies allow the researcher/practitioner to provide ecologically valid scenarios in a safe environment that can be shaped to the needs and skill level of each individual (de Bruin et al., 2010). Furthermore, evidence supports that when VR tasks are designed appropriately participants can learn real world motor tasks, such as billiards (Haar et al., 2021). This is crucial because motor learning in VR is not appealing if the learned skills cannot be applied to the real world. ...
Historically, research aimed at improving motor performance has largely focused on the neural processes involved in motor execution due to their role in muscle activation. However, accompanying somatosensory and proprioceptive sensory information is also vitally involved in performing motor skills. Here we review research from interdisciplinary fields to provide a description for how somatosensation informs the successful performance of motor skills as well as emphasize the need for careful selection of study methods to isolate the neural processes involved in somatosensory perception. We also discuss upcoming strategies of intervention that have been used to improve performance via somatosensory targets. We believe that a greater appreciation for somatosensation's role in motor learning and control will enable researchers and practitioners to develop and apply methods for the enhancement of human performance that will benefit clinical, healthy, and elite populations alike.
... That is, we investigate how demographic variables such as age and gender, and subjective variables such as perceived competence, similarity to the instructor avatar and presence in VR, are influencing the efficacy of avatar customisation using regression analyses. This is in contrast to most psychomotor learning studies, which consider only the overall effects of a learning intervention irrespective of the individual characteristics of the users [56,57,63,97,162]. ...
... We speculate that this difference in perceived competence may instead be due to participants in the screen condition being able to see their own body, enabling better judgement of their accuracy. Many participants in the VR condition indeed reported that they were not sure how well they performed the moves because they could not see themselves, limiting their learning [63]. This could also explain why visual imagery following screen based training tended to be more vivid, and may be a confounding factor which hides the interaction effect between avatar and display types on IVI, EVI, and KVI. ...
... In recent health research, the embodiment of an old avatar was also shown to be effective in an intervention designed to increase intentions to vaccinate [122,179]. Virtual embodiment is also an emerging technology to support motor learning and rehabilitation [54,62,177]. Moreover, a large randomized controlled trial showed that BOIs are effective in the treatment of fear of heights [40]. ...
Body ownership illusions (BOIs) occur when participants experience that their actual body is replaced by a body shown in virtual reality (VR). Based on a systematic review of the cumulative evidence on BOIs from 111 research papers published in 2010 to 2021, this article summarizes the findings of empirical studies of BOIs. Following the PRISMA guidelines, the review points to diverse experimental practices for inducing and measuring body ownership. The two major components of embodiment measurement, body ownership and agency, are examined. The embodiment of virtual avatars generally leads to modest body ownership and slightly higher agency. We also find that BOI research lacks statistical power and standardization across tasks, measurement instruments, and analysis approaches. Furthermore, the reviewed studies showed a lack of clarity in fundamental terminology, constructs, and theoretical underpinnings. These issues restrict scientific advances on the major components of BOIs, and together impede scientific rigor and theory-building.
... Applying implications from these conclusions can cause remarkable adversities among users, especially patients undergoing VR-related clinical intervention. Haar, Sundar, and Faisal (2021) report that VR is among the methodological variables that help people control and maneuver their surroundings, but there is significant ambiguity regarding manipulating the technology. An example of such issues surrounds the puzzle of whether motor learning in VR transmits to the typical world. ...
Virtual reality gains popularity due to its wide range of applications, starting with entertainment and ending with a whole set of educational programs. It surely has its positive sides and drawbacks. The current study focuses on the evaluation of the psychophysical response to the ability to control and manipulate virtual reality. It also focuses on the impact virtual reality has on the ability to perform spatial modeling. The study’s sample includes 140 participants. The research has form of a classic experiment involving two experimental groups and one control group. While the second experimental group consisted of 40 respondents and could only observe virtual reality without being able to influence
their actions in it, the first experimental group consisted of 44 participants who could control their actions in virtual reality (they could move, jump and choose places from which you could look at nature in virtual reality). The control group only passed the proposed tests measuring spatial modeling skills and was not involved in virtual reality. Psychophysical response was measured using a polygraph. The results show that being able to control VR makes the experience more immersive, increasing emotional response and stress, while not being able to control it causes less stress and engagement. The conclusion is that short virtual reality sessions have a positive effect on the ability to perform spatial modeling tasks.
... This strategy may open the door to the use of VR as a training tool for acquiring skills that require significant inter-subject coordination. Insofar, VR training for real world tasks has been demonstrated for activities that introduce significant physical constraints, such as billiards 48 or table tennis 49 . Generalising the use of joint action computational models to a variety of tasks where inter-subject coordination plays a significant part of the task success could unlock the use of VR in a wider variety of training, education and therapy scenarios. ...
Perceptual-motor synchronisation in human groups is crucial in many activities, from musical ensembles to sports teams. To this aim, the mirror game, where partners are asked to imitate each other’s movements or gestures, is one of the best available experimental paradigms to study how humans engage in joint tasks and how they tend to synchronise their behaviour. However, to date, virtual reality characters do not engage in motor synchronisation with human users. In this work, we explored to what extent an autonomous virtual character and a human that play the mirror game in virtual reality can synchronise their behaviour. We created a full-body version of the mirror game with an autonomous virtual character, whose movements were driven by a model based on coupled oscillators. Participants engaged in a joint imitation task with a virtual player animated with one of three options: a model that included a small coupling, a model with no coupling, or another human. Behavioural measures and subjective reports suggest that participants were unable to distinguish the condition of small coupling from the engagement with an avatar driven by another human participant.
