Social exclusion in a virtual Cyberball game reduces the virtual hand illusion

Sense of ownership and agency are two important aspects of the minimal self, but how self-perception is affected by social conditions remains unclear. Here, we studied how social inclusion or exclusion of participants in the course of a virtual Cyberball game would affect explicit judgments and implicit measures of ownership and agency (proprioceptive drift, skin conductance responses, and intentional binding, respectively) in a virtual hand illusion paradigm, in which a virtual hand moved in or out of sync with the participants' own hand. Results show that synchrony affected all four measures. More importantly, this effect interacted with social inclusion/exclusion in the Cyberball game for both ownership and agency measure, showing that social exclusion reduces perceived agency and ownership.

The sense of agency in near and far space

The sense of agency is the ability to recognize that we are the actors of our actions and their consequences. We explored whether and how spatial cues may modulate the agency experience by manipulating the ecological validity of the experimental setup (real-space or computer-based setup) and the distance of the action-outcome (near or far). We tested 58 healthy adults collecting explicit agency judgments and the perceived time interval between movements and outcomes (to quantify the intentional binding phenomenon, an implicit index of agency). Participants show greater implicit agency for voluntary actions when there is a temporal and spatial action-outcome contingency. Conversely, participants reported similar explicit agency for outcomes appearing in the near and far space. Notably, these effects were independent of the ecological validity of the setting. These results suggest that spatial proximity, realistic or illusory, is essential for feeling implicitly responsible for the consequences of our actions.

How aging shapes our sense of agency

The sense of agency refers to the feeling of controlling one's actions and their effects on the external environment. Here, we tested how the physiological process of aging affects the agency experience by taking advantage of a validated ecological experimental paradigm and exploring the different dimensions of agency. We tested 60 young and older adults during active and passive movements, causing, after a variable time delay, an external sensorial event. We collected overt agency judgments (i.e., explicit agency dimension), and we measured the perceived compression of the time interval between the active/passive movements and outcomes (to quantify the intentional binding phenomenon, an implicit index of agency). Our results indicate that the sense of agency significantly changes across the adult life span, with older participants exhibiting a reduced sense of agency, both at the explicit and implicit level. Crucially, the temporal dimension of the action outcome did not affect their agency experience. We suggest that elderly adults are more reliant on internal predictions, making them less sensitive to cognitive biases and external manipulations. We discuss these results in the domain of neurocognitive models of motor control, with reference to how aging affects the weighting process of predictive and sensory signals for efficient sensorimotor integration.

Implicit signatures of voluntary action reduce with repeated motor practice

The sense of controlling one's actions and their consequences is a critical aspect of successful motor activity. While motor performance typically improves with learning, it is unclear whether, how, and why higher order aspects of motor cognition are also affected. Here, we used an implicit measure of sense of agency-the 'intentional binding' effect-as participants learned to make a skilled action involving precise control of thumb adduction. These actions were predictably followed by a tone (the outcome). At pre-test, we showed the perceived time of the tone was shifted towards the thumb action, compared to a control condition in which tones occurred without actions. Next, a relevant training group learned to refine the direction of the thumb movement, while an irrelevant training group was trained on another movement. Manipulation checks demonstrated that, as expected, the relevant training group improved performance of the trained movement, while the irrelevant training group did not. Critically, while both groups still showed binding of the tone towards the thumb action at post-test, the relevant training group showed less binding than the irrelevant training group. Given the link between intentional binding and volitional control of action, we suggest our result demonstrates subjective agency over the outcome of a skilled action decreases as practice makes the skilled action more fluent. We suggest that this reduction in sense of agency over movement outcomes is consistent with the decreasing cognitive engagement, or automatization, that occurs during skill learning.

When did it happen? Verbal information about causal relations affects time estimation

Usually, the closer two events occur, the more likely people infer a causal relationship between them. Recent studies have shown that this relationship between time and causality is bidirectional. Participants also tend to judge events closer in time if they assume that they are causally related. We present six experiments showing causal binding, but unlike other experiments, participants do not emit any motor action, and no physical feedback is given. Rather, all stimuli and causal information are provided verbally. After reading a list of events, participants were asked to estimate the time elapsed between two of them. Those participants who were informed that there was a causal relationship between the two events estimated them as occurring closer to each other. These results support causality- and heuristic-based explanations of temporal binding, as opposed to other explanations such as sensory integration or intentionality of action.

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.

Inhibition of intentional binding by an additional sound presentation

When a voluntary action is followed by an effect after a short delay, the time distance between the action and its effect is perceived to be shorter than the actual time distance. This phenomenon is known as intentional binding (IB). We investigated the influence of presentation of an additional effect on IB between the action and the target effect, and investigated the influence of the presentation timing of the additional effect. One sound (target sound) was constantly presented 250 ms after the button was pressed, and the other sound (additional sound) was presented simultaneously when the button was pressed (Experiment 1) or at one of various timings that included moments both before and after the target sound (Experiment 2). The results showed that IB between the action and target sound was significantly inhibited only when the additional sound was presented prior to the target sound. This suggests that the prior effect has a greater advantage in connecting to the action compared to the posterior sound.

The sense of agency for brain disorders: A comprehensive review and proposed framework

Sense of Agency (SoA) refers to the feeling of control over voluntary actions and the outcomes of those actions. Several brain disorders are characterized by an abnormal SoA. To date, there is no robust treatment for aberrant agency across disorders; this is, in large part, due to gaps in our understanding of the cognitive mechanisms and neural correlates of the SoA. This apparent gap stems from a lack of synthesis in established findings. As such, the current review reconciles previously established findings into a novel neurocognitive framework for future investigations of the SoA in brain disorders, which we term the Agency in Brain Disorders Framework (ABDF). In doing so, we highlight key top-down and bottom-up cues that contribute to agency prospectively (i.e., prior to action execution) and retrospectively (i.e., after action execution). We then examine brain disorders, including schizophrenia, autism spectrum disorders (ASD), obsessive-compulsive disorders (OCD), and cortico-basal syndrome (CBS), within the ABDF, to demonstrate its potential utility in investigating neurocognitive mechanisms underlying phenotypically variable presentations of the SoA in brain disorders.

Mistakes strengthen the temporal binding effect in the context of goal-directed actions

Temporal binding is an illusion in which the temporal interval between two events appears compressed. In the context of intentional actions, this effect is observed as a compression of the perceived interval between these actions and their causal outcomes. This 'intentional binding effect' has been used to investigate the Sense of Agency, which is the experience of intentionally causing an outcome through volitional action. Intentional binding is reduced for negative outcomes such as error feedback, but the role of mistakes (e.g., errors of commission) for binding and agency has not been extensively studied. In our study, participants played a virtual game in which they attempted to 'splat' (hit) visual stimuli that looked like coloured bugs, using mouse clicks. On some trials, stimulus colours changed unpredictably immediately before actions were made, sometimes inducing mistakes. Actions were thus clearly identifiable as mistakes at the time of their onset before any outcome feedback had been provided. Participants reported shorter action-outcome intervals when stimuli changed, but only when this change caused a mistake according to the game's rules. This suggests that intentional binding is strengthened by errors of commission. We discuss how this effect may be accounted for by agency itself and via more general processes such as changes in arousal.

Sense of agency during and following recovery from anorexia nervosa

The need to feel in control is central to anorexia nervosa (AN). The sense of control in AN has only been studied through self-report. This study investigated whether implicit sense of control (sense of agency; SoA) differs across AN patients, recovered AN (RAN) patients and healthy controls (HC). Furthermore, we assessed whether state anxiety is influenced by negative emotional states. SoA was measured with the intentional binding task (IB) and state-anxiety levels through a questionnaire. We did not find any evidence of differences in SoA between groups. Furthermore, state anxiety was not a significant predictor of SoA. Further research into SoA in AN should focus on other features of the SoA that are not targeted by the IB task.

The implicit sense of agency is not a perceptual effect but is a judgment effect

The sense of agency (SoA) is characterized as the sense of being the causal agent of one's own actions, and it is measured in two forms: explicit and implicit. In the explicit SoA experiments, the participants explicitly report whether they have a sense of control over their actions or whether they or somebody else is the causal agent of seen actions; the implicit SoA experiments study how do participants' agentive or voluntary actions modify perceptual processes (like time, vision, tactility, and audition) without directly asking the participants to explicitly think about their causal agency or sense of control. However, recent implicit SoA literature reported contradictory findings of the relationship between implicit SoA reports and agency states. Thus, I argue that the purported implicit SoA reports are not agency-driven perceptual effects per se but are judgment effects, by showing that (a) the typical operationalizations in implicit SoA domain lead to perceptual uncertainty on the part of the participants, (b) under uncertainty, participants' implicit SoA reports are due to heuristic judgments which are independent of agency states, and (c) under perceptual certainty, the typical implicit SoA reports might not have occurred at all. Thus, I conclude that the instances of implicit SoA are judgments (or response biases)-under uncertainty-rather than perceptual effects.

Sense of agency for mental actions: Insights from a belief-based action-effect paradigm

A substantial body of research has converged on the idea that the sense of agency arises from the integration of multiple sources of information. In this study, we investigated whether a measurable sense of agency can be detected for mental actions, without the contribution of motor components. We used a fake action-effect paradigm, where participants were led to think that a motor action or a particular thought could trigger a sound. Results showed that the sense of agency, when measured through explicit reports, was of comparable strength for motor and mental actions. The intentional binding effect, a phenomenon typically associated with the experience of agency, was also observed for both motor and mental actions. Taken together, our results provide novel insights into the specific role of intentional cues in instantiating a sense of agency, even in the absence of motor signals.

Physical load reduces synchrony effects on agency and ownership in the virtual hand illusion

We used the virtual hand illusion paradigm to investigate the effect of physical load on perceived agency and body ownership. Participants pulled a resistance band that required exerting a force of 1 N, 10 N, or 20 N while operating a virtual hand that moved in synchronous or out of sync with their own hand. Explicit agency and ownership ratings were obtained, in addition to intentional binding and skin conductance as implicit measures of agency and ownership. Physical load increased perceived subjective load but showed no main effect, while synchrony effects were found on all agency and ownership measures. Interestingly, load did interact with synchrony in implicit agency and explicit ownership, by reducing and eliminating synchrony effects as movement synchrony was reduced with higher physical load. Furthermore, consistent with previous claims, implicit agency increased with perceived effort associated with higher physical load.

Studying sense of agency online: Can intentional binding be observed in uncontrolled online settings?

Intentional binding is often used as an implicit index of the sense of agency. However, intentional binding research has primarily been conducted in controlled lab environments. During the COVID-19 global pandemic, there has been a shift to implementing studies using online platforms and it is an open question whether the intentional binding effect can be found using an online experimental set-up and participant sample. Here, we address this question by asking online participants to complete the Libet clock version of the intentional binding task, which we make freely available to researchers as a jsPsych (De Leeuw, 2014) plugin. Intentional binding was observed in the form of later keypress estimates and earlier auditory tone estimates, when the auditory tone followed the keypress. These findings confirm that intentional binding can be assessed in online contexts. We discuss these findings in relation to the broader intentional binding literature.

Temporal Binding, Causation, and Agency: Developing a New Theoretical Framework

In temporal binding, the temporal interval between one event and another, occurring some time later, is subjectively compressed. We discuss two ways in which temporal binding has been conceptualized. In studies showing temporal binding between a voluntary action and its causal consequences, such binding is typically interpreted as providing a measure of an implicit or pre-reflective "sense of agency." However, temporal binding has also been observed in contexts not involving voluntary action, but only the passive observation of a cause-effect sequence. In those contexts, it has been interpreted as a top-down effect on perception reflecting a belief in causality. These two views need not be in conflict with one another, if one thinks of them as concerning two separate mechanisms through which temporal binding can occur. In this paper, we explore an alternative possibility: that there is a unitary way of explaining temporal binding both within and outside the context of voluntary action as a top-down effect on perception reflecting a belief in causality. Any such explanation needs to account for ways in which agency, and factors connected with agency, has been shown to affect the strength of temporal binding. We show that principles of causal inference and causal selection already familiar from the literature on causal learning have the potential to explain why the strength of people's causal beliefs can be affected by the extent to which they are themselves actively involved in bringing about events, thus in turn affecting binding.

Temporal binding past the Libet clock: testing design factors for an auditory timer

Voluntary actions and causally linked sensory stimuli are perceived to be shifted towards each other in time. This so-called temporal binding is commonly assessed in paradigms using the Libet Clock. In such experiments, participants have to estimate the timing of actions performed or ensuing sensory stimuli (usually tones) by means of a rotating clock hand presented on a screen. The aforementioned task setup is however ill-suited for many conceivable setups, especially when they involve visual effects. To address this shortcoming, the line of research presented here establishes an alternative measure for temporal binding by using a sequence of timed sounds. This method uses an auditory timer, a sequence of letters presented during task execution, which serve as anchors for temporal judgments. In four experiments, we manipulated four design factors of this auditory timer, namely interval length, interval filling, sequence predictability, and sequence length, to determine the most effective and economic method for measuring temporal binding with an auditory timer.

Neural correlates of implicit agency during the transition from adolescence to adulthood: An ERP study

Sense of agency (SoA), the experience of being in control of our voluntary actions and their outcomes, is a key feature of normal human experience. Frontoparietal brain circuits associated with SoA undergo a major maturational process during adolescence. To examine whether this translates to neurodevelopmental changes in agency experience, we investigated two key neural processes associated with SoA, the activity that is leading to voluntary action (Readiness Potential) and the activity that is associated with the action outcome processing (attenuation of auditory N1 and P2 event related potentials, ERPs) in mid-adolescents (13-14), late-adolescents (18-20) and adults (25-28) while they perform an intentional binding task. In this task, participants pressed a button (action) that delivered a tone (outcome) after a small delay and reported the time of the tone using the Libet clock. This action-outcome condition alternated with a no-action condition where an identical tone was triggered by a computer. Mid-adolescents showed greater outcome binding, such that they perceived self-triggered tones as being temporally closer to their actions compared to adults. Suggesting greater agency experience over the outcomes of their voluntary actions during mid-adolescence. Consistent with this, greater levels of attenuated neural response to self-triggered auditory tones (specifically P2 attenuation) were found during mid-adolescence compared to older age groups. This enhanced attenuation decreased with age as observed in outcome binding. However, there were no age-related differences in the readiness potential leading to the voluntary action (button press) as well as in the N1 attenuation to the self-triggered tones. Notably, in mid-adolescents greater outcome binding scores were positively associated with greater P2 attenuation, and smaller negativity in the late readiness potential. These findings suggest that the greater experience of implicit agency observed during mid-adolescence may be mediated by a neural over-suppression of action outcomes (auditory P2 attenuation), and over-reliance on motor preparation (late readiness potential), which we found to become adult-like during late-adolescence. Implications for adolescent development and SoA related neurodevelopmental disorders are discussed.

Cognitive load dissociates explicit and implicit measures of body ownership and agency

It is often claimed that the human self consists of perceived body ownership and agency, which are commonly assessed through explicit ownership and agency judgments and implicit measures, like proprioceptive drift, skin conductance responses, and intentional binding effects. Bottom-up multisensory integration and top-down modulation were predicted to be important for ownership and agency. In previous studies, cognitive load was revealed to affect the sense of agency in a top-down fashion, but its effect on ownership has not been fully investigated, not even its possibly different effect on explicit and implicit measures. Here we used cognitive load (small vs. large sets in a working-memory task) to disentangle explicit and implicit measures of ownership and agency in a task inducing the virtual hand illusion (VHI; stronger perceived ownership and agency over a virtual hand if it moves in synchrony with one's real hand). Results showed similar patterns for ownership and agency - both ownership and agency were affected by cognitive load, and importantly in the explicit measures, higher load increased the effect of synchrony (i.e., the VHI), but in implicit measures, higher load reduced indications of both ownership and agency. Hence, the load manipulation was selective with regard to the explicit versus implicit nature of the measure but not with respect to the measure's content. This provides strong evidence that explicit and implicit measures of both ownership and agency rely on at least partly separable informational sources, while the difference between ownership and agency as such does not seem to play a major role.

Explicit and implicit measures of body ownership and agency: affected by the same manipulations and yet independent

People are assumed to represent themselves in terms of body ownership and agency. Studies using the rubber- or virtual-hand illusion have assessed ownership and agency by means of explicit ownership and agency ratings and implicit measures, like proprioceptive drift in the case of ownership. These measures often show similar effects but also some discrepancies, suggesting that they rely on data sources that overlap, but not completely. To systematically assess commonalities and discrepancies, we adopted an immersed virtual hand illusion (VHI) design, in which three independent factors were manipulated: the synchrony between the movement of real and virtual effector, the type of effector, which was a virtual hand or triangle, and the spatial congruency between the real and virtual effector. Commonalities and discrepancies in the effects of these factors were assessed by crossing explicit and implicit measures for ownership and agency. While standard ratings were used as explicit measures, implicit ownership was assessed by means of proprioceptive drift and implicit agency by means of intentional binding. Results showed similar effect patterns for the two agency measures, which, however, were not correlated, different effect patterns for the two ownership measures, and a strong correlation between the two explicit measures. Taken altogether, our findings suggest that explicit and implicit measures of ownership and agency partly rely on shared informational sources, but seem to differ with respect to other sources that are integrated or with respect to the processed dimension (shape vs. time). The findings also suggest that some findings obtained with RHI designs might reflect more the unnatural situation that that design puts individuals into rather than generalizable mechanisms of computing perceived ownership and agency.

Intended emotions influence intentional binding with emotional faces: Larger binding for intended negative emotions

The effect of emotions on Intentional binding (IB) is equivocal. In addition, most studies on IB have not manipulated emotional content of intentions. This study investigates the effect of intended and outcome emotions using emotional faces (happy or disgust face in experiment 1 and a happy or angry face in experiment 3). To see whether the effects are due to priming, we used instructions with a happy-disgust pair in experiment 2 and happy-angry pair in experiment 4. Outcome emotional faces were not predictable. Results showed that intending a negative emotional face resulted in shorter action-outcome interval judgments compared to a happy face irrespective of the emotional content of the outcome face. This effect was absent in experiments 2 and 4 with instructed emotions. In addition to showing the importance of having explicit intentions, the results show that emotional content of our intentions does influence IB possibly due to prospective mechanisms.

An experimental paradigm for studying sense of agency in joint human-machine motor actions

In this paper, we propose an experimental technique for studying the sense of agency (SoA) in joint human-machine actions. This technique is based on the use of an electromechanical finger-lifting device that enables a joint motor action initiated by a participant and completed by the machine. The joint action, later referred to as an "active-passive" action, was implemented as a reaction time task and contrasted with other levels of participant's involvement, including active movement, passive movement, and observation of a dummy's movement. In each trial, a feedback sound signal informed the participant whether they had performed the task successfully, i.e. faster than a threshold, which was individually adjusted in the beginning of the experiment. In the active condition, the result depended on the participant, while in other conditions it was preprogrammed for the servo. In context of this task, we studied direct time estimates made by participants and auditory event-related potentials (ERP) in 20 healthy volunteers. The amplitude of the auditory N1 component in the responses to the feedback sound showed no significant effect of activity and success factors, while its latency was shorter in successful trials. Interaction of activity and success factors was significant for subjective time estimates. Surprisingly, the intentional binding effect (subjective compression of time intervals, which is known as a correlate of SoA) only emerged in trials of active condition with negative results. This observation was in contrast with the fact that the active and active-passive movements were both voluntarily initiated by the participant. We believe that studying SoA with the proposed technique may not only add to the understanding of agency but also provide practically relevant results for the development of human-machine systems such as exoskeletons.

Low-level, prediction-based sensory and motor processes are unimpaired in Autism

A new promising account of human brain function suggests that sensory cortices try to optimise information processing via predictions that are based on prior experiences. The brain is thus likened to a probabilistic prediction machine. There has been a growing - though inconsistent - literature to suggest that features of autism spectrum conditions (ASCs) are associated with a deficit in modelling the world through such prediction-based inference. However empirical evidence for differences in low-level sensorimotor predictions in autism is still lacking. One approach to examining predictive processing in the sensorimotor domain is in the context of self-generated (predictable) as opposed to externally-generated (less predictable) effects. We employed two complementary tasks - forcematching and intentional binding - which examine self-versus externally-generated action effects in terms of sensory attenuation and intentional binding respectively in adults with and without autism. The results show that autism was associated with normal levels of sensory attenuation of internally-generated force and with unaltered temporal attraction of voluntary actions and their outcomes. Thus, our results do not support a general deficit in predictive processing in autism.

Intentional action and limitation of personal autonomy. Do restrictions of action selection decrease the sense of agency?

The experience of being an intentional agent is a key component of personal autonomy. Here, we tested how undermining intentional action affects the sense of agency as indexed by intentional binding. In three experiments using the Libet clock paradigm, participants judged the onset of their action (key presses) and resulting effect (auditory stimuli) under conditions of no, partial, or full autonomy over selecting and timing their actions. In all cases, we observed a moderate to strong intentional binding effect. However, we found no evidence for an influence of personal autonomy on intentional binding. These findings thus suggest that being unable to decide how and when to perform actions does not affect the perceived temporal binding between action and effect, a phenomenon suggested to be associated with the implicit sense of agency. We discuss the implications of our findings in the context of research on personal autonomy and goal-directed behavior.

Influence of arousal on intentional binding: Impaired action binding, intact outcome binding

Emotional states have been indicated to affect intentional binding, resulting in an increase or decrease as a function of valence and arousal. Sexual arousal is a complex emotional state proven to impair attentional and perceptual processes, and is therefore highly relevant to feeling in control over one’s actions. We suggest that sexual arousal affects intentional binding in the same way as highly negative arousing states such as fear and anger. Ninety participants performed the intentional binding task before and after watching an either sexually arousing or emotionally neutral film clip. Analyses were conducted for the subcomponents action and outcome binding separately including the change in arousal before and after the emotion induction as a continuous measure. Results showed an interactive effect for time of measurement (before and after emotion induction) and arousal change on action binding: a decrease in action binding was noted in participants who reported to be more aroused and an increase in action binding was observed for participants who reported to be less aroused. Results emphasize that alterations in action binding are likely to reflect the deficits in the dopaminergic system involved in action execution. An impaired feeling of control in aroused states may play a crucial role for the underlying psychological mechanisms of impulsive violent behavior.

Learning from informative losses boosts the sense of agency

Sense of agency, the feeling of having control over one's actions, is modulated by whether one's choices lead to desired or undesired outcomes. Learning similarly depends on outcome values from previous experience. In the current study, we evaluate a possible link between the sense of agency and learning, by investigating how intentional binding, an implicit measure of agency, changes during a probabilistic learning task. In two experiments, we show increased intentional binding in trials that follow losses, compared with trials that follow wins. Experiment 1 demonstrated that this post-error agency boost (PEAB) effect is rule-specific, as it did not occur if the trial following an error involved different action-outcome contingencies. Furthermore, PEAB was not modulated by the type of outcome presentation (monetary vs. affective). Experiment 2 showed that the PEAB effect can also occur when the current action involves a forced (as opposed to free) choice, but only when the previous, loss-provoking action was chosen freely. Thus, PEAB occurs when current actions are informed by outcomes of one's own previous action choices. Electroencephalography (EEG) data linked these effects to two event-related potential components, namely, the Feedback Related Negativity and the P300. Taken together, these results support the notion that PEAB reflects an adaptive property of human sense of agency, facilitating effective learning about the action-outcome structure of a specific task, to optimise future performance. By clarifying the conditions for enhancing the sense of agency through learning, this work adds to our understanding of human learning and agency.

Cue integration as a common mechanism for action and outcome bindings

When a voluntary action is followed by a sensory outcome, their timings are perceived to shift toward each other compared to when they were generated independently. Recent studies have tried to explain this temporal binding effect based on the cue integration theory, in which the timing of action and outcome are estimated as a precision-weighted average of their individual estimates, although distinct results were obtained between the binding of action and outcome. This study demonstrates that cue integration underlies both action and outcome bindings, using visual changes as action outcomes. Participants viewed a moving clock presented on a screen to report the onset time of their action or the feature changes of visual objects that were relevant or irrelevant to the clock movement. The results revealed that the precision of outcome timing judgment was different based on the object that underwent a feature change. Moreover, consistent with the theory's prediction, the perceptual shifts of action and outcome timings were larger and smaller, respectively, when the precision of outcome timing judgments was higher. These results suggest that cue integration serves as a common mechanism in action and outcome bindings.

Sense of agency: Sensorimotor signals and social context are differentially weighed at implicit and explicit levels

Sense of agency (SoA) describes the experience of being the author of an action. Cue integration approaches divide SoA into an implicit level, mostly relying on prospective sensorimotor signals, and an explicit level, resulting from an integration of sensorimotor and contextual cues based on their reliability. Integration mechanisms at each level and the contribution of implicit to explicit SoA remain underspecified. In a task of movements with visual outcomes, we tested the effect of social context (contextual cue) and sensory prediction congruency (retrospective sensorimotor cue) over implicit (intentional binding) and explicit (verbal judgments) SoA. Our results suggest that prospective sensorimotor cues determine implicit SoA. At the explicit level, retrospective sensorimotor cues and contextual cues are partly integrated in an additive way, but contextual cues can also act as a heuristic if sensorimotor cues are highly unreliable. We also found no significant association between implicit and explicit SoA.

The evolving sense of agency: Context recency and quality modulate the interaction between prospective and retrospective processes

Humans acquire a sense of agency through their interactions with the world and their sensory consequences. Previous studies have highlighted stable agency-related phenomena like intentional binding, which depend on both prospective, context-dependent and retrospective, outcome-dependent processes. In the current study, we investigated the interaction between prospective and retrospective processes underlying the adaptation of an ongoing sense of agency. The results showed that prospective intentional binding developed during a temporal window of up to 20 prior events was independent of the nature of the ongoing event. By contrast, the characteristics of the ongoing event retrospectively influenced prospective intentional binding developed during a temporal window narrower than 6 prior events. These findings characterize the interaction between prospective and retrospective mechanisms as a fundamental process to continuously update the sense of agency through sensorimotor learning. High psychosis-like experience traits weakened this interaction, suggesting that reduced adaption to the context contributes to altered self-experience.

Sensorimotor conflicts alter metacognitive and action monitoring

While sensorimotor signals are known to modulate perception, little is known about their influence on higher-level cognitive processes. Here, we applied sensorimotor conflicts while participants performed a perceptual task followed by confidence judgments. Results showed that sensorimotor conflicts altered metacognitive monitoring by decreasing metacognitive performance. In a second experiment, we replicated this finding and extended our results by showing that sensorimotor conflicts also altered action monitoring, as measured implicitly through intentional binding. In a third experiment, we replicated the same effects on intentional binding with sensorimotor conflicts related to the hand rather than to the trunk. However, effects of hand sensorimotor conflicts on metacognitive monitoring were not significant. Taken together, our results suggest that metacognitive and action monitoring may involve endogenous, embodied processes involving sensorimotor signals which are informative regarding the state of the decider.

When robots tell you what to do: Sense of agency in human- and robot-guided actions

The present study investigated the sense of agency (SoA) when actions were determined by another human vs. a humanoid robot as compared to when freely selected. Additionally, perceived robot-autonomy was manipulated via autonomous vs. non-autonomous descriptions of the robot. SoA was assessed by judgment of control ratings and intentional binding (i.e., perceived temporal attraction between voluntary actions and their outcomes). Participants performed free and instructed key presses that produced an auditory tone (Experiment-1) and visual stimuli conveying neutral, positive, or negative valence (Experiment-2). Binding and control ratings were greater in free compared to instructed actions, and comparable between human- and robot-instructed actions. Control ratings were higher for positive compared to neutral and negative outcomes, and positively correlated with ratings of how human-like the robot appeared. These results highlight the role of endogenous processing of action selection and provide preliminary insight into the SoA when actions are guided by artificial agents.

The impact of eye contact on the sense of agency

Recent research suggests that eye contact can lead to enhanced self-awareness. A related phenomenon, the sense of agency deals with the notion of the self as the origin of our actions. Possible links between eye contact and agency have been so far neglected. Here, we investigated whether an implicit sense of agency could be modulated by eye gaze. We asked participants to respond (button press) to a face stimulus: looking or not at the participant (experiment 1); or displaying distinct eye gaze before or after a mask (experiment 2). After each trial, participants estimated the time between their key press and the ensuing effects. We found enhanced intentional binding for conditions that involved direct compared to averted gaze. This study supports the idea that eye contact is an important cue that affects complex cognitive processes and suggests that modulating self-processing can impact the sense of agency.

Environmental control and psychosis-relevant traits modulate the prospective sense of agency in non-clinical individuals

The sense of agency concerns the experience of being the source of one's own actions and their consequences. An altered sense of agency can occur due to task automation and in psychosis. We tested in a non-clinical sample the hypothesis that reducing voluntary task control diminishes intentional binding as an implicit indicator of the sense of agency, possibly interacting with psychosis-relevant personality traits. Agent-device interactions were manipulated obtaining positive-control (voluntary interaction), no-control (automation), and negative-control (device-commanded interaction) groups. The main results showed reduced prospective intentional binding (predictive coding of action consequences) in the no-control and negative-control groups, compared to the positive-control group. Psychosis-like experiences covaried positively with intentional binding in the no-control group, but negatively in the negative-control group. Moreover, positive-social traits were associated with increased intentional binding in the positive-control group. These findings demonstrate the interplay between environmental and individual differences variables in establishing the implicit sense of agency.

Compress global, dilate local: Intentional binding in action-outcome alternations

Intentional binding refers to subjective temporal attraction between an action and its outcome. However, the nature of intentional binding in multiple actions remains unclear. We examined intentional binding in alternated action-outcome dyads. Participants actively or passively pressed a key, followed by a tone, and they again pressed the key; resulting in four keypress-tone dyads in a trial. Participants reproduced the duration of alternated keypress-tone dyads or the temporal interval between a dyad embedded in the alternations. The reproduced duration was shorter in the active than in the passive condition, suggesting the intentional binding in action-outcome alternations. In contrast, the reproduced interval between a dyad was longer in the active condition and did not correlate with the reproduced duration. These results suggest that subjective time during actions relies not only on an internal clock but also on postdictive biases that are switched based on what we recall.

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.

I just lost it! Fear and anger reduce the sense of agency: a study using intentional binding

Two recent studies have demonstrated that increases in arousal states lead to an increase people's sense of agency, i.e., the subjective experience of controlling one's own voluntary actions (Minohara et al. in Front Psychol 7:1165, 2016; Wen et al. in Conscious Cogn 36:87-95, 2015). We here extend these findings by showing that arousal states with negative emotional valence, such as fear and anger, decrease sense of agency. Anger and fear are negative emotional states. Anecdotally, they are often invoked as reasons for losing control, and neuroscientific evidence confirms important effects on the brain's action control systems. Surprisingly, the subjective experience of acting in anger or fear has scarcely been investigated experimentally. Thus, the legal notion that these intense emotions may undermine normal voluntary control over actions and outcomes (the 'Loss of Control', a partial defence for murder) lacks any clear evidence base. In three laboratory experiments, we measured sense of agency using an implicit measure based on time perception (the "intentional binding" paradigm). These actions occurred in either an emotionally neutral condition, or in a fearful (experiments 1 and 2) or angry state (experiment 3). In line with our hypotheses, fear or anger reduced the subjective sense of control over an action outcome, even though the objective causal link between action and outcome remained the same. This gap between the objective facts of agency, and a reduced subjective experience of agency under emotional conditions, has important implications for society and law.

Social exclusion reduces the sense of agency: Evidence from intentional binding

Social exclusion is known to induce an immediate threat to one's perceived sense of control. The sense of agency is an important human experience, strongly associated with volitional action. Healthy participants perceive the temporal interval between a voluntary action and its effect to be shorter than the same interval when it separates an involuntary action and effect. This temporal illusion is known as intentional binding and is used experimentally to index the implicit sense of agency. The current study investigated whether activating memories of social exclusion alters intentional binding. Results show that action-effect interval estimates are significantly longer after remembering an episode of social exclusion than after remembering an episode of social inclusion, or a no priming baseline condition. This study is the first to demonstrate the link between feelings of social exclusion and the pre-reflective sense of agency.

Changes in intentional binding effect during a novel perceptual-motor task

Perceptual-motor learning describes the process of improving the smoothness and accuracy of movements. Intentional binding (IB) is a phenomenon whereby the length of time between performing a voluntary action and the production of a sensory outcome during perceptual-motor control is perceived as being shorter than the reality. How IB may change over the course of perceptual-motor learning, however, has not been explicitly investigated. Here, we developed a set of IB tasks during perceptual-motor learning. Participants were instructed to stop a circular moving object by key press when it reached the center of a target circle on the display screen. The distance between the center of the target circle and the center of the moving object was measured, and the error was used to approximate the perceptual-motor performance index. This task also included an additional exercise that was unrelated to the perceptual-motor task: after pressing the key, a sound was presented after a randomly chosen delay of 200, 500, or 700 ms and the participant had to estimate the delay interval. The difference between the estimated and actual delay was used as the IB value. A cluster analysis was then performed using the error values from the first and last task to group the participants based on their perceptual-motor performance. Participants showing a very small change in error value, and thus demonstrating a small effect of perceptual-motor learning, were classified into cluster 1. Those who exhibited a large decrease in error value from the first to the last set, and thus demonstrated a strong improvement in perceptual-motor performance, were classified into cluster 2. Those who exhibited perceptual-motor learning also showed improvements in the IB value. Our data suggest that IB is elevated when perceptual-motor learning occurs.

Unexpected action outcomes produce enhanced temporal binding but diminished judgement of agency

Sense of agency (SoA) is the feeling of being the author of given actions and their effects. Recent works have investigated the cue integration approach to agency, according to which different predictive and inferential cues form SoA. In the current research we focus on how two such cues, i.e. accuracy of sensorimotor prediction and prior causal belief, influence SoA measured by temporal binding (TB) and questionnaires. Our results show that whereas learnt action effects produce normal TB and explicit agency, unexpected oddball effects produce enhanced TB but diminished explicit agency. Increased binding was modulated by temporal prediction, but not by identity prediction. A few interpretations of the results are given, including cue integration and pre-activation mechanisms. The research casts new light on the mechanisms and dynamics of TB and adds to the evidence for discrepancies between SoA measures.

Robust intentional binding for causally-linked sequences of naturalistic events but not for abstract event sequences

Past studies have shown that when a voluntary action produces a sensory effect, the action and the effect will be perceived as being closer in time. This subjective temporal 'attraction' is known as intentional binding (IB). Induction of IB is dependent on the intentionality of one's actions, the predictability of the effect, and the causality between the action and the effect. Previous investigations of IB have utilized abstract stimuli (e.g., flashes and beeps) with adaptation so as to associate the abstract action-effect link. Yet, events from our everyday experiences already have an inherent action-effect link. We, thus, investigated, for the first time, IB under naturalistic, multisensory stimulation by manipulating the intentionality, predictability, and causal event link. A total of five experiments without adaptation were conducted examining IB with: abstract stimuli (Experiment 1), naturalistic effects (Exp. 2), naturalistic action cue and effect matching (Exp. 3), naturalistic action cue and effect mismatching (Exp. 4), and naturalistic action cue and effect matching but mismatched response mapping (Exp. 5). Analyses of the data showed the absence of IB for abstract stimuli without action-effect adaptation (Exp. 1) and for effects that were not inherently causal or predictable of one's action (Exp. 2, 4, and 5). IB, however, was induced when the naturalistic sequence of action cue-effect was casually linked and predictable in terms of timing (Exp. 3). Overall, our results showed that induction of IB is dependent on the inherent causal and predictable association of an event from the cue to act to the consequence of that action, an association that is already present in everyday multisensory events.

On the relation between body ownership and sense of agency: A link at the level of sensory-related signals

The relation between sense of body ownership and sense of agency is still highly debated. Here we investigated in a large sample of healthy participants the associations between several implicit and explicit indexes of the two senses. Specifically, we examined the correlations between proprioceptive shift (implicit measure) and questionnaire on the subjective experience of ownership (explicit measure) within the rubber hand illusion paradigm (body ownership), and intentional binding (implicit measure), attenuation of the intensity of auditory outcomes of actions (implicit measure) and questionnaire on the subjective experience of authorship (explicit measure) within the Libet's clock paradigm (sense of agency). Our results showed that proprioceptive shift was positively correlated with the attenuation of auditory outcomes. No significant correlations were found between the explicit measures of the two senses. We argue that the individual spatiotemporal constraints subserving the integration of sensory-related signals (implicit signature) would be common to both senses, whereas their subjective experience (explicit signature) would rely on additional processes specific for any given sense.

The role of the temporoparietal junction in implicit and explicit sense of agency

The experience of being in control of one's actions and thier outcomes is called the sense of agency. This is a fundamental feature of our human experience, and may underpin important social functions such as morality and responsibility. Sense of agency can be measured explicitly, by asking people to report their experience, or implicitly by recording the perceived time interval between actions and outcomes (intentional binding). The current studies used transcranial direct current stimulation to assess the role of left and right temporoparietal junction in both implicit and explicit sense of agency. Participants were informed that they could control the volume output of the computer with one of two buttons. Participants experienced reduced sense of agency when the outcome was inconsistent with their action. However, binding did not differ between congruent and incongruent action-outcomes. The modulation of explicit agency ratings by action-outcome congruency was significantly reduced by right TPJ stimulation (experiment 1) but not left TPJ stimulation (experiment 2). Implicit agency was not affected in either stimulation condition. These findings are discussed in terms of the possible neural mechanisms of implicit and explicit sense of agency.

Learning to infer the time of our actions and decisions from their consequences

Research shows that people infer the time of their actions and decisions from their consequences. We asked how people know how much time to subtract from consequences in order to infer their actions and decisions. They could either subtract a fixed, default, time from consequences, or learn from experience how much time to subtract in each situation. In two experiments, participants' actions were followed by a tone, which was presented either immediately or after a delay. In Experiment 1, participants estimated the time of their actions; in Experiment 2, the time of their decisions to act. Both actions and decisions were judged to occur sooner or later as a function of whether consequences were immediate or delayed. Estimations tended to be shifted toward their consequences, but in some cases they were shifted away from them. Most importantly, in all cases participants learned progressively to adjust their estimations with experience.

The effects of freedom of choice in action selection on perceived mental effort and the sense of agency

Previous research showed that increasing the number of action alternatives enhances the sense of agency (SoA). Here, we investigated whether choice space could affect subjective judgments of mental effort experienced during action selection and examined the link between subjective effort and the SoA. Participants performed freely selected (among two, three, or four options) and instructed actions that produced pleasant or unpleasant tones. We obtained action-effect interval estimates to quantify intentional binding - the perceived interval compression between actions and outcomes and feeling of control (FoC) ratings. Additionally, participants reported the degree of mental effort they experienced during action selection. We found that both binding and FoC were systematically enhanced with increasing choice-level. Outcome valence did not influence binding, while FoC was stronger for pleasant than unpleasant outcomes. Finally, freely chosen actions were associated with low subjective effort and slow responses (i.e., higher reaction times), and instructed actions were associated with high effort and fast responses. Although the conditions that yielded the greatest and least subjective effort also yielded the greatest and least binding and FoC, there was no significant correlation between subjective effort and SoA measures. Overall, our results raise interesting questions about how agency may be influenced by response selection demands (i.e., indexed by speed of responding) and subjective mental effort. Our work also highlights the importance of understanding how subjective mental effort and response speed are related to popular notions of fluency in response selection.

Uncovering effects of self-control and stimulus-driven action selection on the sense of agency

The sense of agency refers to feelings of causing one's own action and resulting effect. Previous research indicates that voluntary action selection is an important factor in shaping the sense of agency. Whereas the volitional nature of the sense of agency is well documented, the present study examined whether agency is modulated when action selection shifts from self-control to a more automatic stimulus-driven process. Seventy-two participants performed an auditory Simon task including congruent and incongruent trials to generate automatic stimulus-driven vs. more self-control driven action, respectively. Responses in the Simon task produced a tone and agency was assessed with the intentional binding task - an implicit measure of agency. Results showed a Simon effect and temporal binding effect. However, temporal binding was independent of congruency. These findings suggest that temporal binding, a window to the sense of agency, emerges for both automatic stimulus-driven actions and self-controlled actions.

The influence of performance on action-effect integration in sense of agency

Sense of agency refers to the subjective feeling of being able to control an outcome through one's own actions or will. Prior studies have shown that both sensory processing (e.g., comparisons between sensory feedbacks and predictions basing on one's motor intentions) and high-level cognitive/constructive processes (e.g., inferences based on one's performance or the consequences of one's actions) contribute to judgments of sense of agency. However, it remains unclear how these two types of processes interact, which is important for clarifying the mechanisms underlying sense of agency. Thus, we examined whether performance-based inferences influence action-effect integration in sense of agency using a delay detection paradigm in two experiments. In both experiments, participants pressed left and right arrow keys to control the direction in which a moving dot was travelling. The dot's response delay was manipulated randomly on 7 levels (0-480ms) between the trials; for each trial, participants were asked to judge whether the dot response was delayed and to rate their level of agency over the dot. In Experiment 1, participants tried to direct the dot to reach a destination on the screen as quickly as possible. Furthermore, the computer assisted participants by ignoring erroneous commands for half of the trials (assisted condition), while in the other half, all of the participants' commands were executed (self-control condition). In Experiment 2, participants directed the dot as they pleased (without a specific goal), but, in half of the trials, the computer randomly ignored 32% of their commands (disturbed condition) rather than assisted them. The results from the two experiments showed that performance enhanced action-effect integration. Specifically, when task performance was improved through the computer's assistance in Experiment 1, delay detection was reduced in the 480-ms delay condition, despite the fact that 32% of participants' commands were ignored. Conversely, when no feedback on task performance was given (as in Experiment 2), the participants reported greater delay when some of their commands were randomly ignored. Furthermore, the results of a logistic regression analysis showed that the threshold of delay detection was greater in the assisted condition than in the self-control condition in Experiment 1, which suggests a wider time window for action-effect integration. A multivariate analysis also revealed that assistance was related to reduced delay detection via task performance, while reduced delay detection was directly correlated with a better sense of agency. These results indicate an association between the implicit and explicit aspects of sense of agency.

Intentional binding as a marker of agency across the lifespan

The feeling of control over actions and their external effects is known as Sense of Agency (SoAg). People usually have a distinctive SoAg for events caused by their own actions. However, if the agent is a child or an older person, this feeling of being responsible for the consequences of an action may differ from what an adult would feel. The idea would be that children and elderly may have a reduced SoAg since their frontal lobes are developing or have started to loose their efficiency. The aim of this study was to elucidate whether the SoAg changes across lifespan, using the Intentional Binding (i.e., the temporal attraction between a voluntary action and its sensory consequence) as implicit measure. Data show that children and elderly are characterized by a reduced SoAg as compared to adults. These findings provide a fundamental step in the characterization of SoAg dynamics throughout individuals' lifetime.

Subliminal modulation of voluntary action experience: A neuropsychological investigation

Human voluntary actions are often associated with a distinctive subjective experience termed 'sense of agency'. This experience could be a reconstructive inference triggered by monitoring one's actions and their outcomes, or a read-out of brain processes related to action preparation, or some hybrid of these. Participants pressed a key with the right index finger at a time of their own choice, while viewing a rotating clock. Occasionally they received a mild shock on the same finger. They were instructed to press the key as quickly as possible if they felt a shock. On some trials, trains of subliminal shocks were also delivered, to investigate whether such subliminal cues could influence the initiation of voluntary actions, or the subjective experience of such actions. Participants' keypress were always followed by a tone 250 ms later. At the end of each trial they reported the time of the keypress using the rotating clock display. Shifts in the perceived time of the action towards the following tone, compared to a baseline condition containing only a keypress but no tone, were taken as implicit measures of sense of agency. The subliminal shock train enhanced this "action binding" effect in healthy participants, relative to trials without such shocks. This difference could not be attributed to retrospective inference, since the perceptual events were identical in both trial types. Further, we tested the same paradigm in a patient with anarchic hand syndrome (AHS). Subliminal shocks again enhanced our measure of sense of agency in the unaffected hand, but had a reversed effect on the 'anarchic' hand. These findings suggest an interaction between internal volitional signals and external cues afforded by the external environment. Damage to the neural pathways that mediate interactions between internal states and the outside world may explain some of the clinical signs of AHS.

Having control over the external world increases the implicit sense of agency

The sense of agency refers to the feeling of control over one's actions, and, through them, over external events. One proposed marker of implicit sense of agency is 'intentional binding'-the tendency to perceive voluntary actions and their outcomes as close in time. Another is attenuation of the sensory consequences of a voluntary action. Here we show that the ability to choose an outcome through action selection contributes to implicit sense of agency. We measured intentional binding and stimulus intensity ratings using painful and non-painful somatosensory outcomes. In one condition, participants chose between two actions with different probabilities of producing high or low intensity outcomes, so action choices were meaningful. In another condition, action selection was meaningless with respect to the outcome. Having control over the outcome increased binding, especially when outcomes were painful. Greater sensory attenuation also tended to be associated with stronger binding of the outcome towards the action that produced it. Previous studies have emphasised the link between sense of agency and initiation of voluntary motor actions. Our study shows that the ability to control outcomes by discriminative action selection is another key element of implicit sense of agency. It also investigates, for the first time, the relation between binding and sensory attenuation for the same events.

Multi-scale control influences sense of agency: Investigating intentional binding using event-control approach

Control exercised by humans through interactions with the environment is critical for sense of agency. Here, we investigate how control at multiple levels influence implicit sense of agency measured using intentional binding. Participants are asked to hit a moving target using a joystick with noisy control followed by an intentional binding task initiated by the target hitting action. Perceptual-motor level control was manipulated through noise in the joystick controller (experiment 1) and goal-level control in terms of feedback about successful hit (experiments 2a and 2b). In the first experiment, intentional binding increased with amount of joystick control only when goal was not achieved and independent otherwise suggesting that the two levels interact hierarchically. In the second experiment, the estimated duration was dependent on when participants knew about goal completion. The results are similar to those obtained with explicit measures of sense of agency indicating that multi-scale event control influences agency.

Temporal distortion in the perception of actions and events

In everyday life, actions and sensory events occur in complex sequences, with events triggering actions that in turn give rise to additional events and so on. Earlier work has shown that a sensory event that is triggered by a voluntary action is perceived to have occurred earlier in time than an identical event that is not triggered by an action. In other words, events that are believed to be caused by our actions are drawn forward in time towards our actions. Similarly, when a sensory event triggers an action, that event is again drawn in time towards the action and is thus perceived to have occurred later than it really did. This alteration in time perception serves to bind together events and actions that are causally linked. It is not clear, however, whether or not the perceived timing of a sensory event embedded within a longer series of actions and sensory events is also temporally bound to the actions in that sequence. In the current study, we measured the temporal binding in sequences consisting of two simple dyads of event-action and action-event in a series of manual action tasks: an event-action-event triad (Experiment 1) and an action-event-action triad (Experiment 2). Auditory tones either triggered an action or were presented 250ms after an action was performed. To reduce the influence of sensory events other than the tone, such as a noise associated with pressing a key on a keyboard, we used an optical sensor to detect hand movements where no contact was made with a surface. In Experiment 1, there appeared to be no change in the perceived onset of an auditory tone when the onset of that tone followed a hand movement and then the tone triggered a second hand movement. It was as if the temporal binding between the action and the tone and then the tone and the subsequent action summed algebraically and cancelled each other out. In Experiment 2, both the perceived onset of an initial tone which triggered an action and the perceived onset of a second tone which was presented 250ms after the action were temporally bound to the action. Taken together, the present study suggests that the temporal binding between our actions and sensory events occur separately in each dyad within a longer sequence of actions and events.