Control Changes the Way We Look at the World

Agency effects on the binding of event elements in episodic memory

Representing events in episodic memory in a coherent manner requires that their constituent elements are bound together. So far, only few moderators of these binding processes have been identified. Here we investigate whether the presence of an agentic element in an event facilitates binding. The results from six experiments provided no evidence for a facilitating effect of agency on the binding of event elements. In addition, binding effects were only found when event elements were presented simultaneously, but not when they were presented sequentially pairwise, contrary to previous findings. The results suggest that the presence of an agentic element in an event does not, or only to a very limited extent, contribute to the formation of coherent memory representations and that additional processes may be required when binding event elements across temporarily divided encoding episodes. These findings add to a growing body of research regarding moderators and processes relevant for the binding of event elements in episodic memory. Explanations of these findings and directions for future research are discussed.

Action-outcome delays modulate the temporal expansion of intended outcomes

The phenomenon of intentional binding pertains to the perceived connection between a voluntary action and its anticipated result. When an individual intends an outcome, it appears to subjectively extend in time due to a pre-activation of the intended result, particularly evident at shorter action-outcome delays. However, there is a concern that the operationalisation of intention might have led to a mixed interpretation of the outcome expansion attributed to the pre-activation of intention, given the sensitivity of time perception and intentional binding to external cues that could accelerate the realisation of expectations. To investigate the expansion dynamics of an intended outcome, we employed a modified version of the temporal bisection task in two experiments. Experiment 1 considered the action-outcome delay as a within-subject factor, while experiment 2 treated it as a between-subject factor. The results revealed that the temporal expansion of an intended outcome was only evident under the longer action-outcome delay condition. We attribute this observation to working memory demands and attentional allocation due to temporal relevancy and not due to pre-activation. The discrepancy in effects across studies is explained by operationalising different components of the intentional binding effect, guided by the cue integration theory. Moreover, we discussed speculative ideas regarding the involvement of specific intentions based on the proximal intent distal intent (PIDI) theory and whether causality plays a role in temporal binding. Our study contributes to the understanding of how intention influences time perception and sheds light on how various methodological factors, cues, and delays can impact the dynamics of temporal expansion associated with an intended outcome.

Effects of Vibration-Based Generation of Timing of Tactile Perception on Upper Limb Function After Stroke: A Case Study

Sensorimotor dysfunction of the fingers and hands hinders the recovery of motor function post-stroke. Generally, hemiplegic patients are unable to properly control the dynamic friction generated between their fingers and objects during hand/finger muscle activity. In addition to sensory information, a sense of agency generated by the temporal synchronization of sensory prediction and sensory feedback is required to control this dynamic friction. In the present study, we utilized a novel rehabilitation device that transmits real-time fingertip contact information to a transducer in a case of stroke hemiplegia with sensorimotor deficits and stagnated hand/finger motor performance. Post-intervention, the patient's upper extremity motor function score (FMA-UE), which had previously been in a state of arrested recovery, improved from 51/66 to 61/66, especially in the wrist joints. Excessive grip force during object grasping and frequency of falling objects was notably decreased post-intervention. We believe that rehabilitation tasks using perceptual generation via transducer will be a new tool for the rehabilitation of post-stroke hand/finger sensorimotor deficits.

Metacognition and sense of agency

Intelligent agents need to understand how they can change the world, and how they cannot change it, in order to make rational decisions for their forthcoming actions, and to adapt to their current environment. Previous research on the sense of agency, based largely on subjective ratings, failed to dissociate the sensitivity of sense of agency (i.e., the extent to which individual sense of agency tracks actual instrumental control over external events) from judgment criteria (i.e., the extent to which individuals self-attribute agency independent of their actual influence over external events). Furthermore, few studies have examined whether individuals have metacognitive access to the internal processes underlying the sense of agency. We developed a novel two-alternative-forced choice (2FAC) control detection task, in which participants identified which of two visual objects was more strongly controlled by their voluntary movement. The actual level of control over the target object was manipulated by adjusting the proportion of its motion that was driven by the participant's movement, compared to the proportion driven by a pre-recorded movement by another agent, using a staircase to hold 2AFC control detection accuracy at 70%. Participants identified which of the two visual objects they controlled, and also made a binary confidence judgment regarding their control detection judgment. We calculated a bias-free measure of first-order sensitivity (d') for detection control at any given level of participant's own movement. The proportion of pre-recorded movements determined by the stairecase could then be used as an index of control detection ability. We identified two distinct processes underlying first-order detection of control: one based on instantaneous sensory predictions for the current movement, and one based on detection of a regular motor-visual relation across a series of movements. Further, we found large individual differences across 40 particpants in metacognitive sensitivity (meta-d') even though first-order sensitivity of control detection was well controlled. Using structural equation modelling (SEM), we showed that metacognition was negatively correlated with the predictive process component of detection of control. This result is inconsistent with previous hypotheses that detection of control relies on metacognitive monitoring of a predictive circuit. Instead, it suggests that predictive mechanisms that compute sense of agency may operate unconsciously.

Prepared to stop: how sense of agency in a preceding trial modulates inhibitory control in the current trial

Feeling in control of actions and events can enhance motivation for further actions. How this sense of agency (SoA) in fact influences flexible motor control remains poorly understood. Here, we investigated the effect of SoA on subsequent response inhibition in a modified go/no-go task with EEG recordings. We manipulated participants' SoA by varying the presence, predictability, and emotional valence of a visual outcome for a given motor action. When participants unexpectedly did not receive any visible outcome following their action on trial n - 1, they exhibited slower responses and lower hit rates to the go signal but higher rates of successful inhibition to the no-go signal on trial n, regardless of the emotional valence of the expected action outcome. Furthermore, enhanced inhibitory tendencies were accompanied by reduced N2 and P3 amplitudes, midfrontal theta power, and theta synchronization between midfrontal and medial to parietal areas, indicating that less top-down control is required for successful response inhibition on trial n after experiencing low SoA on trial n - 1. These findings suggest that feeling less in control in a preceding trial makes it easier to implement inhibitory control in the current trial, thereby providing new insights into the role of SoA in goal-directed behavior.

Ready to go: Higher sense of agency enhances action readiness and reduces response inhibition

Sense of agency is the subjective feeling of being in control of one's actions and their effects. Many studies have elucidated the cognitive and sensorimotor processes that drive this experience. However, less is known about how sense of agency influences flexible cognitive and motor control. Here, we investigated the effect of sense of agency on subsequent action regulation using a modified Go/No-Go task. In Experiment 1, we modulated participants' sense of agency by varying the occurrence of action outcomes (present vs. absent) both locally on a trial-by-trial basis and globally in terms of the overall probability of action outcomes within a block of trials (high vs. low). Importantly, we investigated how this manipulation influenced participants' responses to subsequent Go, No-Go, or Free-Choice cues. When participants' previous action led to an outcome (i.e., a happy face) compared with no outcome, they responded more accurately and faster to Go cues, reacted less accurately to No-Go cues, as well as made go decisions more frequently and faster to Free-Choice cues. These effects were even stronger when action outcomes occurred more frequently overall in a given block or in several previous trials. Experiment 2 further demonstrated that the effects of action outcome manipulation on subsequent action regulation were independent of the emotional valence of the action outcome (i.e., a happy or an angry face). Our results suggest that a higher sense of agency as induced by the presence of action outcomes enhanced action readiness and suppressed response inhibition. These findings highlight the impact of the control felt on the control used in action regulation, thereby providing new insights into the functional significance of the sense of agency on human behavior.

Better Controlled, Better Maintained: Sense of Agency Facilitates Working Memory

The cognitive effects of sense of agency (SoA) attract increasing attention. It is unclear how SoA influences working memory (WM). In the present study, participants first moved several boxes. One of the boxes was more or less controllable than the majority. After boxes stopped moving, to-be-remembered items appeared. Memory performance and SoA over them were subsequently tested. In Experiments 1a and 1b, the majority of boxes, serving as context, were under low and high control respectively. To further examine whether the maintenance stage was influenced, the effect of selective encoding was minimized in Experiments 2a and 2b. Experiment 2b further eliminated the impact of agency judgments and tested the relationship among SoA, WM, and preference. Memory was better for items with strong SoA in the high and low control contexts. The effect partly stems from the modulation of the maintenance stage in WM, in which reward-based processes could be engaged.

Vicarious ostracism reduces observers' sense of agency

Previous findings revealed that social ostracism reduces people's implicit sense of agency. Based on theoretical claims that observed behavior of others may be cognitively represented similarly to one's own behavior, we conducted two experiments to test whether people's own sense of agency can also be impaired by observed social exclusion of others. In Experiment 1, participants recalled episodes referring to vicarious ostracism or inclusion before completing a temporal interval estimation task to assess intentional binding effects (an established implicit measure of the sense of agency). In Experiment 2, participants immersed into a newly designed virtual Cyberball game, in which they witnessed a vicarious ostracism or inclusion scenario, before completing a Libet-style temporal estimation task and an agency questionnaire (an explicit measure of the sense of agency). The findings show, for the first time, that vicarious ostracism reduces both implicit and explicit measures of agency in observers.

Being active over one's own motion: Considering predictive mechanisms in self-motion perception

Self-motion perception is a key element guiding pilots' behavior. Its importance is mostly revealed when impaired, leading in most cases to spatial disorientation which is still today a major factor of accidents occurrence. Self-motion perception is known as mainly based on visuo-vestibular integration and can be modulated by the physical properties of the environment with which humans interact. For instance, several studies have shown that the respective weight of visual and vestibular information depends on their reliability. More recently, it has been suggested that the internal state of an operator can also modulate multisensory integration. Interestingly, the systems' automation can interfere with this internal state through the loss of the intentional nature of movements (i.e., loss of agency) and the modulation of associated predictive mechanisms. In this context, one of the new challenges is to better understand the relationship between automation and self-motion perception. The present review explains how linking the concepts of agency and self-motion is a first approach to address this issue.

Adaptability of the Sense of Agency in Healthy Young Adults in Sensorimotor Tasks for a Short Term

Sense of agency (SoA) refers to the subjective feeling of controlling one's own actions and sensory feedback. The SoA occurs when the predicted feedback matches the actual sensory feedback and is responsible for maintaining behavioral comfort. However, sensorimotor deficits because of illness cause incongruence between prediction and feedback, so the patient loses comfort during actions. Discomfort with actions associated with incongruence may continue robustly (i.e., "not" adaptable) throughout life because of the aftereffects of the disease. However, it is unclear how the SoA modulates when incongruency is experienced, even for a short term. The purpose of this study was to investigate the adaptability of the SoA in healthy participants in sensorimotor tasks for a short term. Participants were divided into congruent and incongruent exposure groups. The experimental task of manipulating the ratio of the self-control of a PC cursor was used to measure the SoA before and after exposure to congruent or incongruent stimuli. The results showed no significant differences between the groups before and after exposure for a short term. The finding that the SoA was not adaptable may assist in guiding the direction of future studies on how to correct incongruence.

Active self-motion control and the role of agency under ambiguity

Purpose

Self-motion perception is a key factor in daily behaviours such as driving a car or piloting an aircraft. It is mainly based on visuo-vestibular integration, whose weighting mechanisms are modulated by the reliability properties of sensory inputs. Recently, it has been shown that the internal state of the operator can also modulate multisensory integration and may sharpen the representation of relevant inputs. In line with the concept of agency, it thus appears relevant to evaluate the impact of being in control of our own action on self-motion perception.

Methodology

Here, we tested two conditions of motion control (active/manual trigger versus passive/ observer condition), asking participants to discriminate between two consecutive longitudinal movements by identifying the larger displacement (displacement of higher intensity). We also tested motion discrimination under two levels of ambiguity by applying acceleration ratios that differed from our two "standard" displacements (i.e., 3 s; 0.012 m.s^-2 and 0.030 m.s^-2).

Results

We found an effect of control condition, but not of the level of ambiguity on the way participants perceived the standard displacement, i.e., perceptual bias (Point of Subjective Equality; PSE). Also, we found a significant effect of interaction between the active condition and the level of ambiguity on the ability to discriminate between displacements, i.e., sensitivity (Just Noticeable Difference; JND).

Originality

Being in control of our own motion through a manual intentional trigger of self-displacement maintains overall motion sensitivity when ambiguity increases.

Sense of agency may not improve recollection and familiarity in recognition memory

Sense of agency (SoA) is a feeling of controlling one's own action. Recognition memory can improve for stimuli that involve SoA perhaps because of the self-reference effect. Recognition memory consists of recollection (i.e., detailed memory of stimuli) and familiarity (i.e., a feeling that stimuli are in memory). The self-reference effect is often observed in the recollection. Here, we investigated whether SoA particularly improves the recollection process. Participants pressed a key to produce an outcome (i.e., box movement followed by word presentation in Experiment 1 or word presentation in Experiment 2) and rated their SoA over the outcome. The outcome was spatially congruent or incongruent with the action. The participants learned the words intentionally (Experiment 1) or incidentally (Experiment 2). Performances of recollection and familiarity were assessed using the remember/know procedure. Our results suggest that the participants' SoA was successfully manipulated. However, contrary to our hypothesis and previous findings, we found no effects of voluntary action and action-outcome congruence on recollection and familiarity processes of recognition memory, regardless of the latency of word presentation and learning strategies. Further studies are needed to replicate and elucidate the relationship between the SoA and recognition memory.

What is new with Artificial Intelligence? Human–agent interactions through the lens of social agency

In this article, we suggest that the study of social interactions and the development of a “sense of agency” in joint action can help determine the content of relevant explanations to be implemented in artificial systems to make them “explainable.” The introduction of automated systems, and more broadly of Artificial Intelligence (AI), into many domains has profoundly changed the nature of human activity, as well as the subjective experience that agents have of their own actions and their consequences – an experience that is commonly referred to as sense of agency. We propose to examine the empirical evidence supporting this impact of automation on individuals’ sense of agency, and hence on measures as diverse as operator performance, system explicability and acceptability. Because of some of its key characteristics, AI occupies a special status in the artificial systems landscape. We suggest that this status prompts us to reconsider human–AI interactions in the light of human–human relations. We approach the study of joint actions in human social interactions to deduce what key features are necessary for the development of a reliable sense of agency in a social context and suggest that such framework can help define what constitutes a good explanation. Finally, we propose possible directions to improve human–AI interactions and, in particular, to restore the sense of agency of human operators, improve their confidence in the decisions made by artificial agents, and increase the acceptability of such agents.

Task-irrelevant object response to action enhances the sense of agency for controlling the object in automation

The sense of agency (SoA) refers to the experience of controlling our bodies and tools. Recent automated systems require the operators to have less manual control, which decreases the SoA. This study investigated how to increase the SoA when operating automated systems, by focusing on the effect of an object's responses to operators' actions on the SoA. Participants applied brakes to a moving black circle by pressing a key, in order to stop the circle near a goal. Then, they estimated their SoA for stopping the circle. We informed them that there were automatic control trials in which the circle stopped independently of their keypress (86% of the trials). The circle's color briefly changed to white (i.e., flashed) when they pressed the key in a half of the automatic control trials. The SoA was higher with the flash than without it. However, the SoA neither increased when the circle flashed independently of a keypress nor when another object flashed due to a keypress. Furthermore, the keypress contingent object-flash did not influence the SoA when the participants controlled the circle manually. These results indicated that spatiotemporally contingent object responses to actions can enhance the SoA in automatic control situations.

Interactions among endogenous, exogenous, and agency-driven attentional selection mechanisms in interactive displays

Attentional selection is driven, in part, by a complex interplay between endogenous and exogenous cues. Recently, one's interactions with the physical world have also been shown to bias attention. Specifically, the sense of agency that arises when our actions cause predictable outcomes biases our attention toward those things which we control. We investigated how this agency-driven attentional bias interacts with simultaneously presented endogenous (words) and exogenous (color singletons) environmental cues. Participants controlled the movement of one object while others moved independently. In a subsequent search task, targets were either the previously controlled objects or not. Targets were also validly or invalidly cued. Both cue types influenced attention allocation. Endogenous cues and agency-driven attentional selection were independent and additive, indicating they are separable mechanisms of selection. In contrast, exogenous cues eliminated the effects of agency, indicating that perceptually salient environmental cues can override internally derived effects of agency. This is the first demonstration of a boundary condition on agency-driven selection.

Perception and control: individual difference in the sense of agency is associated with learnability in sensorimotor adaptation

Adaptive motor learning refers to the ability to adjust to novel disturbances in the environment as a way of minimizing sensorimotor errors. It is known that such processes show large individual differences and are linked to multiple perceptual and cognitive processes. On the other hand, the sense of agency refers to the subjective feeling of control during voluntary motor control. Is the sense of agency just a by-product of the control outcome, or is it actually important for motor control and learning? To answer this question, this study takes an approach based on individual differences to investigate the relationship between the sense of agency and learnability in sensorimotor adaptation. Specifically, we use an adaptive motor learning task to measure individual differences in the efficiency of motor learning. Regarding the sense of agency, we measure the perceptual sensitivity of detecting an increase or a decrease in control when the actual level of control gradually increases or decreases, respectively. The results of structure equation modelling reveal a significant influence of perceptual sensitivity to increased control on motor learning efficiency. On the other hand, the link between perceptual sensitivity to decreased control and motor learning is nonsignificant. The results show that the sense of agency in detecting increased control is associated with the actual ability of sensorimotor adaptation: people who are more sensitive in detecting their control in the environment can also more quickly adjust their behaviors to novel disturbances to acquire better control, compared to people who have a less sensitive sense of agency. Finally, the results also reveal that the processes of increasing control and decreasing control may be partially independent.

Deceleration Assistance Mitigated the Trade-off Between Sense of Agency and Driving Performance

Driving assistance technology has gained traction in recent years and is becoming more widely used in vehicles. However, drivers usually experience a reduced sense of agency when driving assistance is active even though automated assistance improves driving performance by reducing human error and ensuring quick reactions. The present study examined whether driving assistance can maintain human sense of agency during early deceleration in the face of collision risk, compared with manual deceleration. In the experimental task, participants decelerate their vehicle in a driving simulator to avoid collision with a vehicle that suddenly cut in front of them and decelerated. In the assisted condition, the system performed deceleration 100 ms after the cut-in. Participants were instructed to decelerate their vehicle and follow the vehicle that cut-in. This design ensured that the deceleration assistance applied a similar control to the vehicle as the drivers intended to, only faster and smoother. Participants rated their sense of agency and their driving performance. The results showed that drivers maintained their sense of agency and improved driving performance under driving assistance. The findings provided insights into designing driving assistance that can maintain drivers' sense of agency while improving future driving performance. It is important to establish a mode of joint-control in which the system shares the intention of human drivers and provides improved execution of control.

Mind Wandering Influences EEG Signal in Complex Multimodal Environments

The phenomenon of mind wandering (MW), as a family of experiences related to internally directed cognition, heavily influences vigilance evolution. In particular, humans in teleoperations monitoring partially automated fleet before assuming manual control whenever necessary may see their attention drift due to internal sources; as such, it could play an important role in the emergence of out-of-the-loop (OOTL) situations and associated performance problems. To follow, quantify, and mitigate this phenomenon, electroencephalogram (EEG) systems already demonstrated robust results. As MW creates an attentional decoupling, both ERPs and brain oscillations are impacted. However, the factors influencing these markers in complex environments are still not fully understood. In this paper, we specifically addressed the possibility of gradual emergence of attentional decoupling and the differences created by the sensory modality used to convey targets. Eighteen participants were asked to (1) supervise an automated drone performing an obstacle avoidance task (visual task) and (2) respond to infrequent beeps as fast as possible (auditory task). We measured event-related potentials and alpha waves through EEG. We also added a 40-Hz amplitude modulated brown noise to evoke steady-state auditory response (ASSR). Reported MW episodes were categorized between task-related and task-unrelated episodes. We found that N1 ERP component elicited by beeps had lower amplitude during task-unrelated MW, whereas P3 component had higher amplitude during task-related MW, compared with other attentional states. Focusing on parieto-occipital regions, alpha-wave activity was higher during task-unrelated MW compared with others. These results support the decoupling hypothesis for task-unrelated MW but not task-related MW, highlighting possible variations in the "depth" of decoupling depending on MW episodes. Finally, we found no influence of attentional states on ASSR amplitude. We discuss possible reasons explaining why. Results underline both the ability of EEG to track and study MW in laboratory tasks mimicking ecological environments, as well as the complex influence of perceptual decoupling on operators' behavior and, in particular, EEG measures.

Modified sensory feedback enhances the sense of agency during continuous body movements in virtual reality

The sense of agency refers to the feeling of control over one's own actions, and through them, the external events. This study examined the effect of modified visual feedback on the sense of agency over one's body movements using virtual reality in healthy individuals whose motor control was disturbed. Participants moved a virtual object using their right hand to trace a trajectory (Experiment 1) or a leading target (Experiment 2). Their motor control was disturbed by a delay in visual feedback (Experiment 1) or a 1-kg weight attached to their wrist (Experiment 2). In the offset conditions, the virtual object was presented at the median point between the desired position and the participants' actual hand position. In both experiments, participants reported improved sense of agency in the offset condition compared to the aligned condition where the visual feedback reflected their actual body movements, despite their motion being less precise in the offset condition. The results show that sense of agency can be enhanced by modifying feedback to motor tasks according to the goal of the task, even when visual feedback is discrepant from the actual body movements. The present study sheds light on the possibility of artificially enhancing body agency to improve voluntary motor control.

Having a sense of agency can improve memory

In most situations, we are able to tell those outcomes we cause from those we do not. By now, research has provided us with a reasonably good understanding of the cognitive processes that underlie this sense of agency - it is thought to be produced by a comparison between a prediction of the outcome and the actual outcome that occurs. What is less clear is whether having a sense of agency can, itself, influence cognition. In the current study, we examined the possibility that sense of agency can affect memory, and we report evidence that stimuli that one feels a sense of agency over are, in fact, better remembered than counterparts without this. This self-agency effect can be distinguished from previously described control-related memory enhancements and adds to what we know of the cognitive consequences of having a sense of agency.

New measures of agency from an adaptive sensorimotor task

Self-agency, the sense that one is the author or owner of one’s behaviors, is impaired in multiple psychological and neurological disorders, including functional movement disorders, Parkinson’s Disease, alien hand syndrome, schizophrenia, and dystonia. Existing assessments of self-agency, many of which focus on agency of movement, can be prohibitively time-consuming and often yield ambiguous results. Here, we introduce a short online motion tracking task that quantifies movement agency through both first-order perceptual and second-order metacognitive judgments. The task assesses the degree to which a participant can distinguish between a motion stimulus whose trajectory is influenced by the participant’s cursor movements and a motion stimulus whose trajectory is random. We demonstrate the task’s reliability in healthy participants and discuss how its efficiency, reliability, and ease of online implementation make it a promising new tool for both diagnosing and understanding disorders of agency.

Categorical Perception of Control

The self is a distinct entity from the rest of the world, and actions and sensory feedback are our channels of interaction with the external world. This study examined how the sense of control influences people's perception of sensorimotor input under the framework of categorical perception. Twenty human participants (18 males, two females) took part in both experiments. Experiment 1 showed that the sensitivity (d') of detecting a 20% change in control from no change was higher when the changes occurred at the control-category boundary than within each category. Experiment 2 showed that the control categories greatly affected early attention allocation, even when the judgment of control was unnecessary to the task. Taken together, these results showed that our perceptual and cognitive systems are highly sensitive to small changes in control that build up to a determinant change in the control category within a relatively narrow boundary zone between categories, compared with a continuous, gradual physical change in control.

The Active Sensing of Control Difference

In everyday life, people control objects in the world around them to varying degrees. The processes people actively use to establish their control, while interacting with an environment containing large ambiguity, remain unknown. This study examines how people explore their control over the environment and how they detect small differences in control among objects. In the experimental task, participants moved three dots on a screen and identified one dot over which the level of control is different from that of the other two. The results support a two-step behavior mechanism underlying the sensing of control difference: People first explore their overall control in the environment, and then the results of the initial exploration are used to selectively tune the direction (i.e., either more or less) of the detected control difference, ensuring efficient and rapid detection of the type of control difference that is potentially important for further action selections.

Attentional selection is biased towards controllable stimuli

While the factors that contribute to individuals feeling a sense agency over a stimulus have been extensively studied, the cognitive effects of a sense of agency over a stimulus are little known. Here, we conducted three experiments examining whether attentional selection is biased towards controllable stimuli. In all three experiments, participants moved four circle stimuli, one of which was under their control. A search target then appeared on one of the stimuli. In Experiment 1, the target was always on the controlled stimulus, but we manipulated the degree of control the participant had. In Experiment 2, the controlled stimulus was the target on 50% of the trials. In Experiment 3, we used a central arrow cue to tell participants which arrow key to press (rather than using a free choice task) and made the controlled stimulus the target on 25% of the trials, making it nonpredictive of the target's location. Across the three experiments we found that visual selection was biased towards controllable stimuli. This attentional bias was larger when participants had full, rather than partial, control over the stimulus, indicating that sense of agency leads one to prioritize objects under their control. The fact that agency influenced attention when the controlled object contained the target in 100%, 50%, and 25% of trials, and occurred even when participants needed to monitor the center of the display in order to know which arrow key to press, suggests that its influence does not depend on task relevance or volitional decision-making.

Improvement of Sense of Agency During Upper-Limb Movement for Motor Rehabilitation Using Virtual Reality

Sense of agency refers to the feeling of controlling one's own body. Many patients surviving from a stroke lose the sense of agency over their body. This is due to impairments in both motor control and sensory brain functions. As a result of this lack in the sense of agency, stroke patients tend to lose the intention of moving the paralyzed limb, which results in further deterioration of brain functions and worsening muscles and joints. The present study proposes a motor rehabilitation system using virtual reality to improve the sense of agency during upper-limb movement which is required for various daily life activities such as eating meals and operating devices. Specifically, participants were instructed to move their hand to track a moving target ball in a virtual reality environment, while the position of their real hand was measured via a motion capture system. Participants were shown another ball presenting the position of their hand in virtual reality. We tested the proposed system with healthy participants, of which the motor control was disturbed by a 1-kg weight attached on the wrist. Participants reported their sense of agency after each trial. The results showed that the sense of agency was enhanced by the proposed intervention. Our results pointed out a potentially useful method to improve the sense of agency during body movements using modified visual feedback, which may contribute to the development of rehabilitation for stroke patients.

The Sense of Agency in Driving Automation

Driving automation has been developing rapidly during the latest decade. However, all current technologies of driving automation still require human drivers’ monitoring and intervention. This means that during driving automation, the control by human driver and by the driving automation system are blended. In this case, if the human driver loses the sense of agency over the vehicle, he/she may not be able to actively engage in driving, and may excessively rely on the driving automation system. This review focuses on the subjective feeling of agency of the human driver over the vehicle in such situations. We address the possible measures of agency in driving automation, and discuss the insights from literatures on the sense of agency in joint control, robotics, automation, and driving assistance. We suggest that maintaining the sense of agency for human driver is important for ethical and safety reasons. We further propose a number of avenues for further research, which may help to better design an optimized driving automation considering human sense of agency.

Prediction error and regularity detection underlie two dissociable mechanisms for computing the sense of agency

The sense of agency refers to the subjective feeling of controlling one's own actions, and through them, events in the outside world. According to computational motor control models, the prediction errors from comparison between the predicted sensory feedback and actual sensory feedback determine whether people feel agency over the corresponding outcome event, or not. This mechanism requires a model of the relation between action and outcome. However, in a novel environment, where this model has not yet been learned, the sense of agency must emerge during exploratory behaviours. In the present study, we designed a novel control detection task, in which participants explored the extent to which they could control the movement of three dots with a computer mouse, and then identified the dot that they felt they could control. Pre-recorded motions were applied for two dots, and the participants' real-time motion only influenced one dot's motion (i.e. the target dot). We disturbed participants' control over the motion of the target dot in one of two ways. In one case, we applied a fixed angular bias transformation between participant's movements and dot movements. In another condition, we mixed the participant's current movement with replay of another movement, and used the resulting hybrid signal to drive visual dot position. The former intervention changes the match between motor action and visual outcome, but maintains a regular relation between the two. In contrast, the latter alters both matching and motor-visual correlation. Crucially, we carefully selected the strength of these two perturbations so that they caused the same magnitude of impairment of motor performance in a simple reaching task, suggesting that both interventions produced comparable prediction errors. However, we found the visuomotor transformation had much less effect on the ability to detect which dot was under one's own control than did the nonlinear disturbance. This suggests a specific role of a correlation-like mechanism that detects ongoing visual-motor regularity in the human sense of agency. These regularity-detection mechanisms would remain intact under the linear, but not the nonlinear transformation. Human sense of agency may depend on monitoring ongoing motor-visual regularities, as well as on detecting prediction errors.

Sense of agency in continuous action is influenced by outcome feedback in one-back trials

Sense of agency (SoA) is a subjective feeling that a person controls his/her own actions and causes changes in the external world. In continuous action such as controlling a dot by keypresses, SoA is influenced by actual actions during the task. Additionally, it is known that even though the actual actions were almost identical, outcome feedback (e.g., success or fail) could modulate SoA, indicating a retrospective modulation of SoA. However, it was unclear whether the SoA modulated by outcome feedback would influence SoA for an up-coming action. Here, we investigated the effects of outcome feedback in one-back trial on SoA in the present trial (i.e., prospective modulation). We conducted three experiments where participants controlled a dot to a target whose color changed unpredictably between white and blue. If the dot reached the target when the color was white (blue), participants received a text feedback of "Success" ("Fail"). However, in fact, we predetermined the outcome feedback to remove the effects of the actual performance of participants on SoA. The results showed that if the outcome feedback of the one-back trial was successful, SoA of the present trial became higher (i.e., prospective modulation) until they received the outcome feedback. Moreover, the prospectively modulated SoA was retrospectively overwritten by the outcome feedback of the present trial and likely converged to a constant level. These findings indicated that SoA was not produced by a mere sum of the prospective and retrospective factors, but rather that these factors independently influenced SoA with differential time courses.

Does delay in feedback diminish sense of agency? A review

Sense of agency refers to the subjective feeling of controlling one's own action, and through it, external events. Action-effect delay is widely used to disrupt this subjective feeling. Numerous studies have shown that self-reported sense of agency decreases along with the increase in delay. I discussed the distinction between body and external agency, and the possible different effects of delay on them. Furthermore, I reviewed literature that examined the influence of delay on self-reported sense of agency, implicit measures of sense of agency, and control-based action selection, and discussed possible reasons of the reported effects. Delay influences the measures of agency via multiple possible processes, such as graded response, task performance, sensory pre-activation, and temporal perceptual sensitivity. However, the causal relation between action and effect at higher-level of judgment may remain intact even for super-second delays. I conclude that the effects of delay on the sense of agency significantly differ between different levels, and researchers willing to use delay to disturb the sense of agency should carefully clarify which process it may affect.

Sensorimotor contingency modulates breakthrough of virtual 3D objects during a breaking continuous flash suppression paradigm

To investigate how embodied sensorimotor interactions shape subjective visual experience, we developed a novel combination of Virtual Reality (VR) and Augmented Reality (AR) within an adapted breaking continuous flash suppression (bCFS) paradigm. In a first experiment, participants manipulated novel virtual 3D objects, viewed through a head-mounted display, using three interlocking cogs. This setup allowed us to manipulate the sensorimotor contingencies governing interactions with virtual objects, while characterising the effects on subjective visual experience by measuring breakthrough times from bCFS. We contrasted the effects of the congruency (veridical versus reversed sensorimotor coupling) and contingency (live versus replayed interactions) using a motion discrimination task. The results showed that the contingency but not congruency of sensorimotor coupling affected breakthrough times, with live interactions displaying faster breakthrough times. In a second experiment, we investigated how the contingency of sensorimotor interactions affected object category discrimination within a more naturalistic setting, using a motion tracker that allowed object interactions with increased degrees of freedom. We again found that breakthrough times were faster for live compared to replayed interactions (contingency effect). Together, these data demonstrate that bCFS breakthrough times for unfamiliar 3D virtual objects are modulated by the contingency of the dynamic causal coupling between actions and their visual consequences, in line with theories of perception that emphasise the influence of sensorimotor contingencies on visual experience. The combination of VR/AR and motion tracking technologies with bCFS provides a novel methodology extending the use of binocular suppression paradigms into more dynamic and realistic sensorimotor environments.

Enhanced perceptual processing of self-generated motion: Evidence from steady-state visual evoked potentials

The sense of agency emerges when our voluntary actions produce anticipated or predictable outcomes in the external world. It remains unclear how the sense of control also influences our perception of the external world. The present study examined perceptual processing of self-generated motion versus non-self-generated motion using steady-state visual evoked potentials (SSVEPs). Participants continuously moved their finger on a touchpad to trigger the movements of two shapes (Experiment 1) or two groups of dots (Experiment 2) on a monitor. Degree of control was manipulated by varying the spatial relation between finger movement and stimulus trajectory across conditions. However, the velocity, onset time, and offset time of visual stimuli always corresponded to participants' finger movement. Stimuli flickered at a frequency of either 7.5 Hz or 10 Hz, thus SSVEPs of these frequencies and their harmonics provided a frequency-tagged measurement of perceptual processing. Participants triggered the motion of all stimuli simultaneously, but had greater levels of control over some stimuli than over others. Their task was to detect a brief colour change on the border(s) of one shape (Experiment 1) or of one group of dots (Experiment 2). Although control over shapes/dots was irrelevant to the visual detection task, we found stronger SSVEPs for stimuli that were under a high level of control, compared with the stimuli that were under a low level of control. Our results suggest that the spatial regularity between self-generated movements and visual input boosted the neural responses underlying perceptual processing. Our results support the preactivation account of sensory attenuation, suggesting that perceptual processing of self-generated events is enhanced rather than inhibited.