Sensorimotor experience in virtual reality enhances sense of agency associated with an avatar

Sensorimotor Simulation's Influence on Stress: EEG and Autonomic Responses in Digital Interviews

This study explored the role of sensorimotor simulation in modulating the stress response in individuals exposed to stressful digital simulated interviews. Participants were assigned to two different versions of a Digital Social Stress Test: a simulated version with a dynamic-realistic examining committee (Dyn-DSST) and a version with a static examining committee (Stat-DSST). During interview preparation, behavioral indices reflecting stress regulation and resistance, response times, and electroencephalographic (EEG) and autonomic indices were collected. Higher regulation scores were found for the Stat-DSST group compared to the Dyn-DSST group, probably induced by the presence of limited external sensory input in time and space, perceived as less stressful. The EEG results revealed a distinct contribution of the low- and high-frequency bands for both groups. Dyn-DSST required greater cognitive regulation effort due to the presence of a continuous flow of information, which can enhance sensory and motor activation in the brain. The SCR increased in the Dyn-DSST group compared to the Stat-DSST group, reflecting greater emotional involvement in the Dyn-DSST group and reduced sensory stimulation in the static version. In conclusion, the results suggest that sensorimotor simulation impacts the stress response differently in dynamic interviews compared to static ones, with distinct profiles based on behavioral, EEG, and autonomic measures.

Neural correlates of an illusionary sense of agency caused by virtual reality

Sense of agency (SoA) is the sensation that self-actions lead to ensuing perceptual consequences. The prospective mechanism emphasizes that SoA arises from motor prediction and its comparison with actual action outcomes, while the reconstructive mechanism stresses that SoA emerges from retrospective causal processing about the action outcomes. Consistent with the prospective mechanism, motor planning regions were identified by neuroimaging studies using the temporal binding (TB) effect, a behavioral measure often linked to implicit SoA. Yet, TB also occurs during passive observation of another's action, lending support to the reconstructive mechanism, but its neural correlates remain unexplored. Here, we employed virtual reality (VR) to modulate such observation-based SoA and examined it with functional magnetic resonance imaging (fMRI). After manipulating an avatar hand in VR, participants passively observed an avatar's "action" and showed a significant increase in TB. The binding effect was associated with the right angular gyrus and inferior parietal lobule, which are critical nodes for inferential and agency processing. These results suggest that the experience of controlling an avatar may potentiate inferential processing within the right inferior parietal cortex and give rise to the illusionary SoA without voluntary action.

Environmental enrichment through virtual reality as multisensory stimulation to mitigate the negative effects of prolonged bed rest

Prolonged bed rest causes a multitude of deleterious physiological changes in the human body that require interventions even during immobilization to prevent or minimize these negative effects. In addition to other interventions such as physical and nutritional therapy, non-physical interventions such as cognitive training, motor imagery, and action observation have demonstrated efficacy in mitigating or improving not only cognitive but also motor outcomes in bedridden patients. Recent technological advances have opened new opportunities to implement such non-physical interventions in semi- or fully-immersive environments to enable the development of bed rest countermeasures. Extended Reality (XR), which covers augmented reality (AR), mixed reality (MR), and virtual reality (VR), can enhance the training process by further engaging the kinesthetic, visual, and auditory senses. XR-based enriched environments offer a promising research avenue to investigate the effects of multisensory stimulation on motor rehabilitation and to counteract dysfunctional brain mechanisms that occur during prolonged bed rest. This review discussed the use of enriched environment applications in bedridden patients as a promising tool to improve patient rehabilitation outcomes and suggested their integration into existing treatment protocols to improve patient care. Finally, the neurobiological mechanisms associated with the positive cognitive and motor effects of an enriched environment are highlighted.

Emergence of sense of body ownership but not agency during virtual tool-use training is associated with an altered body schema

In this study we examined if training with a virtual tool in augmented reality (AR) affects the emergence of ownership and agency over the tool and whether this relates to changes in body schema (BS). 34 young adults learned controlling a virtual gripper to grasp a virtual object. In the visuo-tactile (VT) but not the vision-only (V) condition, vibro-tactile feedback was applied to the palm, thumb and index fingers through a CyberTouch II glove when the tool touched the object. Changes in the forearm BS were assessed with a tactile distance judgement task (TDJ) where participants judged distances between two tactile stimuli applied to their right forearm either in proximodistal or mediolateral orientation. Participants further rated their perceived ownership and agency after training. TDJ estimation errors were reduced after training for proximodistal orientations, suggesting that stimuli oriented along the arm axis were perceived as closer together. Higher ratings for ownership were associated with increasing performance level and more BS plasticity, i.e., stronger reduction in TDJ estimation error, and after training in the VT as compared to the V feedback condition, respectively. Agency over the tool was achieved independent of BS plasticity. We conclude that the emergence of a sense of ownership but not agency depends on performance level and the integration of the virtual tool into the arm representation.

Tool-use training in augmented reality: plasticity of forearm body schema does not predict sense of ownership or agency in older adults

In young adults (YA) who practised controlling a virtual tool in augmented reality (AR), the emergence of a sense of body ownership over the tool was associated with the integration of the virtual tool into the body schema (BS). Agency emerged independent of BS plasticity. Here we aimed to replicate these findings in older adults (OA). Although they are still able to learn new motor tasks, brain plasticity and learning capacity are reduced in OA. We predicted that OA would be able to gain control over the virtual tool indicated by the emergence of agency but would show less BS plasticity as compared to YA. Still, an association between BS plasticity and body ownership was expected. OA were trained in AR to control a virtual gripper to enclose and touch a virtual object. In the visuo-tactile (VT) but not the vision-only (V) condition, vibro-tactile feedback was applied through a CyberTouch II glove when the tool touched the object. BS plasticity was assessed with a tactile distance judgement task where participants judged distances between two tactile stimuli applied to their right forearm. Participants further rated their perceived ownership and agency after training. As expected, agency emerged during the use of the tool. However, results did not indicate any changes in the BS of the forearm after virtual tool-use training. Also, an association between BS plasticity and the emergence of body ownership could not be confirmed for OA. Similar to YA, the practice effect was stronger in the visuo-tactile feedback condition compared with the vision-only condition. We conclude that a sense of agency may strongly relate to improvement in tool-use in OA independent of alterations in the BS, while ownership did not emerge due to a lack of BS plasticity.

Optimized virtual reality-based Method of Loci memorization techniques through increased immersion and effective memory palace designs: a feasibility study

For most, an improvement in memory would always be desirable, whether from the point of view of an aging individual with declining memory, or from the perspective of someone seeking to memorize large amounts of information in the shortest period of time. One way for people to improve upon their memory performance is by using the Method of Loci (MoL), a famously complex, ancient memorization technique for non-spatial information recall. With the use of virtual reality technology, this technique can finally be easily taught to individuals for use in their daily lives. In this paper, we present an exploration into this avenue of using MoL in virtual reality and report on the design and evaluation of our new virtual memory palace that aims to prove the feasibility of improving upon designs from other studies to optimize memory recall performance. An experiment was conducted to evaluate our VR MoL environment. The results from week 1 on the pre-test (M = 62.55, SD = 24.01) and post-test (M = 82.91, SD = 15.99) memory task showed an increase in the number of words remembered was statistically significant, t(20) = -2.34, p = 0.014 where participants were able to remember approximately 20.4% more non-spatial information, when compared to traditional memorization techniques. After a second use, participants improved, remembering 22.2% more non-spatial information on the pre-test (M = 63.44, SD = 26.64) and post-test (M = 85.67, SD = 16.10) memory task, indicating that the increase in number of words remembered was statistically significant, t(16) = -2.142, p = 0.024. The results suggest that the virtual memory palace experience could be optimized to help participants learn the MoL technique with very little training time and potentially produce significant improvements in recall performance as a result.

Self-Illusion: A Study on Cognition of Role-Playing in Immersive Virtual Environments

We present the design and results of an experiment investigating the occurrence of self-illusion and its contribution to realistic behavior consistent with a virtual role in virtual environments. Self-illusion is a generalized illusion about one's self in cognition, eliciting a sense of being associated with a role in a virtual world, despite sure knowledge that this role is not the actual self in the real world. We validate and measure self-illusion through an experiment where each participant occupies a non-human perspective and plays a non-human role using this role's behavior patterns. 77 participants were enrolled for the user study according to the priori power analysis. In the mixed-design experiment with different levels of manipulations, we asked the participants to play a cat (a non-human role) within an immersive VE and captured their different kinds of responses, finding that the participants with higher self-illusion can connect themselves to the virtual role more easily. Based on statistical analysis of questionnaires and behavior data, there is some evidence that self-illusion can be considered a novel psychological component of presence because it is dissociated from sense of embodiment (SoE), plausibility illusion (Psi), and place illusion (PI). Moreover, self-illusion has the potential to be an effective evaluation metric for user experience in a virtual reality system for certain applications.

The effects of embodying wildlife in virtual reality on conservation behaviors

Efforts to mitigate environmental threats are often inversely related to the magnitude of casualty, human or otherwise. This “compassion fade” can be explained, in part, by differential processing of large- versus small-scale threats: it is difficult to form empathic connections with unfamiliar masses versus singular victims. Despite robust findings, little is known about how non-human casualty is processed, and what strategies override this bias. Across four experiments, we show how embodying threatened megafauna-Loggerhead sea turtles (Caretta Caretta)-using virtual reality can offset and reverse compassion fade. After observing compassion fade during exposure to non-human casualty in virtual reality (Study 1; N = 60), we then tested a custom virtual reality simulation designed to facilitate body transfer with a threatened Loggerhead sea turtle (Study 2; N = 98). Afterwards, a field experiment (Study 3; N = 90) testing the simulation with varied number of victims showed body transfer offset compassion fade. Lastly, a fourth study (N = 25) found that charitable giving among users embodying threatened wildlife was highest when exposed to one versus several victims, though this effect was reversed if victims were of a different species. The findings demonstrate how animal embodiment in virtual reality alters processing of environmental threats and non-human casualty, thereby influencing conservation outcomes.

Validation of a low-cost inertial motion capture system for whole-body motion analysis

While some low-cost inertial motion capture (IMC) systems are now commercially available, generally, they have not been evaluated against gold standard optical motion capture (OMC). The objective was to validate the low-cost Neuron IMC system with OMC. Whole-body kinematics were recorded on five healthy subjects during manual handling of boxes for about 32 min while wearing 17 magnetic and inertial measurement units with Optotrak clusters serving as a reference. The kinematical model was calibrated anatomically for OMC and with poses for IMC. Local coordinate systems were aligned with angular velocities to dissociate differences due to technology or kinematical model. Descriptive statistics including the root mean square error (RMSE), coefficient of multiple correlation (CMC) and limits of agreement (LoA) were applied to the joint angle curves. The average technological error yielded 5.8° and 4.9° for RMSE, 0.87 and 0.96 for CMC and 0.4 ± 8.6° and -0.3 ± 6.0° for LoA about the frontal and transverse axes respectively, whereas the longitudinal axis yielded 10.5° for RMSE, 0.78 for CMC and 3.3 ± 13.1° for LoA. Differences due to technology and to the model contributed similarly to the total difference between IMC and OMC. For many joints and axes, RMSE stayed under 5°, CMC over 0.9 and LoA under 10°, especially for the transverse axis and lower limb. The Neuron low-cost IMC system showed potential for tracking complex human movements of long duration in a normal laboratory environment with a certain error level that may be suitable for many applications involving large IMC distribution.

Virtual skills training: the role of presence and agency

Virtual reality (VR) simulations provide increased feelings of presence and agency that could allow increased skill improvement during VR training. Direct relationships between active agency in VR and skill improvement have previously not been investigated. This study examined the relationship between (a) presence and agency, and (b) presence and skills improvement, via active and passive VR simulations and through measuring real-world golf-putting skill. Participants (n = 23) completed baseline putting skill assessment before using an Oculus Rift VR head-mounted display to complete active (putting with a virtual golf club) and passive (watching a game of golf) VR simulations. Measures of presence and agency were administered after each simulation, followed by a final putting skill assessment. The active simulation induced higher feelings of general presence and agency. However, no relationship was identified between presence and either agency or skill improvement. No skill improvement was evident in either the active or passive simulations, potentially due to the short training period applied, as well as a lack of realism in the VR simulations inhibiting a transfer of skills to a real environment. These findings reinforce previous literature that shows active VR to increase feelings of presence and agency. This study generates a number of fruitful research questions about the relationship between presence and skills training.

Misplacing memories? An enactive approach to the virtual memory palace

In this paper, we evaluate the pragmatic turn towards embodied, enactive thinking in cognitive science, in the context of recent empirical research on the memory palace technique. The memory palace is a powerful method for remembering yet it faces two problems. First, cognitive scientists are currently unable to clarify its efficacy. Second, the technique faces significant practical challenges to its users. Virtual reality devices are sometimes presented as a way to solve these practical challenges, but currently fall short of delivering on that promise. We address both issues in this paper. First, we argue that an embodied, enactive approach to memory can better help us understand the effectiveness of the memory palace. Second, we present design recommendations for a virtual memory palace. Our theoretical proposal and design recommendations contribute to solving both problems and provide reasons for preferring an embodied, enactive account over an information-processing treatment of the memory palace.

The relationship and difference between delay detection ability and judgment of sense of agency

Judgment of agency involves the comparison of motor intention and proprioceptive/visual feedback, in addition to a range of cognitive factors. However, few studies have experimentally examined the differences or correlations between delay detection ability and judgment of agency. Thus, the present study investigated the relationship between delay detection ability and agency judgment using the delay detection task and the agency attribution task. Fifty-eight participants performed the delay detection and agency attribution tasks, and the time windows of each measure were analyzed using logistic curve fitting. The results revealed that the time window of judgment of agency was significantly longer than that of delay detection, and there was a slight correlation between the time windows in each task. The results supported a two-step model of agency, suggesting that judgment of agency involved not only comparison of multisensory information but also several cognitive factors. The study firstly revealed the model in psychophysical experiments.