Intentional Binding Research Articles

Constraining the Sense of Agency in Human-Machine Interaction

One of the most significant issues in Human-Machine Interaction relates to how much autonomy delegates to automation and whether this could degrade the human perception of control, referred to as Sense of Agency. In this study, the What-Whether-When model of intentional action was used to look for variations in the Sense of Agency by measuring the Intentional Binding effect when the human is told either what action to perform or whether to act or when to act. Participants were asked to reproduce the time interval between a keypress and an acoustic tone (delivered at different time intervals). In Experiment 1, this action could be entirely voluntary or fully constrained by the computer. In Experiment 2, the computer constrained only one decision component at a time (either what, whether, or when). Experiment 1 indicates that Intentional Binding is increased for voluntary actions. Results from Experiment 2 suggest that selecting what to do, whether, and when to act have different effects, with the Sense of Agency being degraded when participants were told what action to perform and whether to act. Further, results show the presence of a specific window of opportunity needed for the Sense of Agency to develop for each constraint.

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.

Sense of agency predicts severity of moral judgments.

Sense of Agency (SoA) refers to the awareness of being the agent of our own actions. A key feature of SoA relies on the perceived temporal compression between our own actions and their sensory consequences, a phenomenon known as "Intentional Binding." Prior studies have linked SoA to the sense of responsibility for our own actions. However, it is unclear whether SoA predicts the way we judge the actions of others - including judgments of morally wrong actions like harming others. To address this issue, we ran an on-line pilot experiment where participants underwent two different tasks designed to tap into SoA and moral cognition. SoA was measured using the Intentional Binding task which allowed us to obtain both implicit (Intentional Binding) and explicit (Agency Rating) measures of SoA. Moral cognition was assessed by asking the same participants to evaluate videoclips where an agent could deliberately or inadvertently cause suffering to a victim (Intentional vs. Accidental Harm) compared with Neutral scenarios. Results showed a significant relation between both implicit and explicit measures of SoA and moral evaluation of the Accidental Harm scenarios, with stronger SoA predicting stricter moral judgments. These findings suggest that our capacity to feel in control of our actions predicts the way we judge others' actions, with stronger feelings of responsibility over our own actions predicting the severity of our moral evaluations of other actions. This was particularly true in ambiguous scenarios characterized by an incongruency between an apparently innocent intention and a negative action outcome.

Understanding the effects of hand design on embodiment in virtual reality

Abstract Understanding user perceptions of interacting with the virtual world is one of the research focuses in recent years, given the rapid proliferation of virtual reality (VR) and driven to establish the metaverse. Users can generate a familiar connection between their bodies and the virtual world by being embodied in virtual hands, and hand representations can induce users’ embodiment in VR. The sense of embodiment represents the cognitive awareness of one's manifestation and includes three subcomponents: the sense of body ownership, agency and self-location. There is insufficient evidence in the literature about the effects of hand designs on the embodiment, especially based on studying its three subcomponents. This study investigates how virtual hand designs with five realism levels influence the three subcomponents of embodiment in VR. This research employs a self-report questionnaire commonly used in the literature to assess embodiment and evaluates agency and self-location by introducing implicit methods (intentional binding and proprioceptive measurement) derived from psychology. Besides, the objective data of eye tracking is used to explore the connection between embodiment and hand designs, and classifying participants’ eye tracking data to help analyze the link between embodiment and user attention. Overall, this research makes a major contribution through a systematic exploration of users’ embodied experience in VR and offers important evidence of the effects of virtual hand designs on body ownership, agency, and self-location, respectively. In addition, this study provides a valuable reference for further investigation of embodiment through implicit and objective methods, and practical design recommendations for virtual hand design in VR applications.

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 250ms 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.

Time Compression Induced by Voluntary-Action and Its Underlying Mechanism: The Role of Eye Movement in Intentional Binding (IB)

Time Compression Induced by Voluntary-Action and Its Underlying Mechanism: The Role of Eye Movement in Intentional Binding (IB)

Depressive traits are associated with a reduced effect of choice on intentional binding

A sense of agency (SoA) over wilful actions is thought to be dependent on the level of choice and the nature of the outcome. In a preregistered study, we manipulated choice and valence of outcome to assess the relationship between SoA across the depression and psychosis continuum. Participants (N = 151) completed a Libet Clock task, in which they had either a free or forced choice to press one of two buttons and received either a rewarding or punishing outcome. Participants also completed questionnaires on depressive and psychosis-like traits. Rewarding outcomes increased intentional binding. The evidence favoured no effect of choice on average, but this was influenced by inter-individual differences. Individuals reporting more depressive traits had less of a difference in intentional binding between free and forced choice conditions. We show that implicit SoA is sensitive to outcome valence and the effect of choice differs across the depression continuum.

Human-likeness and attribution of intentionality predict vicarious sense of agency over humanoid robot actions

Sense of Agency (SoA) is the feeling of being in control of one’s actions and their outcomes. In a social context, people can experience a “vicarious” SoA over another human’s actions; however, it is still controversial whether the same occurs in Human–Robot Interaction (HRI). The present study aimed at understanding whether humanoid robots may elicit vicarious SoA in humans, and whether the emergence of this phenomenon depends on the attribution of intentionality towards robots. We asked adult participants to perform an Intentional Binding (IB) task alone and with the humanoid iCub robot, reporting the time of occurrence of both self- and iCub-generated actions. Before the experiment, participants’ degree of attribution of intentionality towards robots was assessed. Results showed that participants experienced vicarious SoA over iCub-generated actions. Moreover, intentionality attribution positively predicted the magnitude of vicarious SoA. In conclusion, our results highlight the importance of factors such as human-likeness and attribution of intentionality for the emergence of vicarious SoA towards robots.

The relationship between interoception and agency and its modulation by heartbeats: an exploratory study

Interoception, the sense of the internal physiological state of the body, theoretically underpins aspects of self-representation. Experimental studies link feelings of body ownership to interoceptive perception, yet few studies have tested for association between the sense of agency and interoceptive processing. Here, we combined an intentional binding paradigm with cardiac measures of interoceptive processing (behavioural performance on a heartbeat discrimination task, and effects of timing within the cardiac cycle) in twenty-six non-clinical participants as an exploratory study. We found performance accuracy on the heartbeat discrimination task correlated positively with the intentional binding effect, an index of sense of agency (β = 0.832, p = 0.005), even after controlling for effects of age, sex, educational level, heart rate, heart rate variability and time accuracy. The intentional binding effect was enhanced during cardiac systole (compared to diastole) in individuals with greater heartbeat discrimination accuracy (β = 0.640, p = 0.047). These findings support the proposal that interoception contributes to mechanisms underlying the emergence of sense of agency.

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.

Phenomenological control as cold control.

We first review recent work from our laboratory, which construes hypnotizability as an example of a more general trait of capacity for phenomenological control, which people can use to create subjective experiences in many nonhypnotic contexts where those experiences fulfill people's goals. Second, we review recent work, which construes phenomenological control as a specifically metacognitive process, where intentional cognitive and motor action occurs without awareness of specific intentions (cold control theory). In terms of the reach of phenomenological control, we argue that various laboratory phenomena, namely vicarious pain, mirror-touch synesthesia, and the rubber hand illusion are to an unknown degree a construction of phenomenological control. The argument can of course be extended in principle to other findings. In terms of the reach of cold control, we present a new theory of intentional binding and show how intentional binding can measure the absence of conscious intentions in the hypnotic context. We obtain no evidence that cold control confers abilities beyond the changes in the metacognitive monitoring it postulates, and we explore the negative correlation between mindfulness and cold control viewed as a lack of mindfulness of intentions.

Intentional binding and self-transcendence: Searching for pro-survival behavior in sense-of-agency

Sense-of-agency (SoA) is implicated in a wide range of pro-survival behavioral capacities from a classical psychological perspective. However, in recent years, SoA has primarily been considered a sensorimotor process indexed by intentional binding, and pro-survival behavioral capacity has been considered multifactorial. To revisit their association, considering such conceptual updates, we examined the relationship between intentional binding and eight factors of pro-survival behavioral capacity (as defined by the power-to-live questionnaire). The level of intentional binding measured using the Libet clock method was significantly correlated with, and contributed to, the self-transcendence factor of the power-to-live questionnaire. The results demonstrated the contribution of the sensorimotor processes of SoA to pro-survival behavioral quality in the domain of self-transcendence, which may be explained by a recent social-cognitive hypothesis for the development from contingency detection to social embeddedness and moral compliance.

Diverging implicit measurement of sense of agency using interval estimation and Libet clock

Besides relying on explicit agency ratings, research concerning the sense of agency seeks to employ implicit measures. One such measure is intentional binding, i.e., the shortening of the perceived temporal interval between an action and its consequence. Multiple paradigms have been used to measure intentional binding. Our aim was to compare two common paradigms within the same participants: interval estimation and the Libet clock paradigm. As both are supposed to measure intentional binding, we hypothesized the two measures correlated positively. In two experiments, we used Bayes factors as a stopping criterion for data collection in a correlational study design resulting in valid samples of 46 and 36 healthy adult students. Despite good reliability, Bayes factors showed moderate evidence for intentional binding from the two paradigms to be uncorrelated. Implications for future research of sense of agency and the necessity for nomological validity of its measures are discussed.

Hand dominance in the performance and perceptions of virtual reach control

PurposeEfforts to optimize human-computer interactions are becoming increasingly prevalent, especially with virtual reality (VR) rehabilitation paradigms that utilize engaging interfaces. We hypothesized that motor and perceptional behaviors within a virtual environment are modulated uniquely through different modes of control of a hand avatar depending on limb dominance. This study investigated the effects of limb dominance on performance and concurrent changes in perceptions, such as time-based measures for intentional binding, during virtual reach-to-grasp. MethodsParticipants (n = 16, healthy) controlled a virtual hand through their own hand motions with control adaptations in speed, noise, and automation. ResultsA significant (p < 0.01) positive relationship between performance (reaching pathlength) and binding (time-interval estimation of beep-sound after grasp contact) was observed for the dominant hand. Unique changes in performance (p < 0.0001) and binding (p < 0.0001) were observed depending on handedness and which control mode was applied. ConclusionsDevelopers of VR paradigms should consider limb dominance to optimize settings that facilitate better performance and perceptional engagement. Adapting VR rehabilitation for handedness may particularly benefit unilateral impairments, like hemiparesis or single-limb amputation.

Intentional binding as an implicit measure of the sense of agency

Intentional binding (IB) is the effect of the subjective temporal attraction of an action and its result. This effect is often viewed as an implicit measure of the sense of agency — a person's awareness of his or her own actions. In our review, we conduct an analysis of various studies reporting the correlation between IB and the sense of agency. We take into account a number of relevant differences between experimental methods, e.g., various techniques for measuring IB. Our review also considers the emergence of IB in the performance of joint actions, as well as the influence of factors such as the delay between the action and the signal, the modality of the signal, the valence of the result of the action, and so on. We conclude that IB manifests itself differently depending on the way it is measured, i.e. the uniform nature of the effect is dubious. IB is influenced by both low-level and high-level processes, which interact with each other and modulate the strength of the effect to varying degrees. As a result, the effect reflects not only the presence of the sense of agency but also the predictability of events in the experiment, as well as the presence of a representation of an action. At the same time, one of the sources of ambiguity in the existing studies is the use of different concepts of the sense of agency by different authors, which is reflected in the interpretations of the results. At the end of the review, we formulate recommendations for future experiments which are meant to take into account the methodological shortcomings of the existing studies. We also point out the most promising directions in the research of IB and present some conceptual difficulties in interpreting the experimental results.

“Clickable” Albumin Binders for Modulating the Tumor Uptake of Targeted Radiopharmaceuticals

The intentional binding of radioligands to albumin gains increasing attention in the context of radiopharmaceutical cancer therapy as it can lead to an enhanced radioactivity uptake into the tumor lesions and, thus, to a potentially improved therapeutic outcome. However, the influence of the radioligand's albumin-binding affinity on the time profile of tumor uptake has been only partly addressed so far. Based on the previously identified Nε-4-(4-iodophenyl)butanoyl-lysine scaffold, we designed "clickable" lysine-derived albumin binders (cLABs) and determined their dissociation constants toward albumin by novel assay methods. Structure-activity relationships were derived, and selected cLABs were applied for the modification of the somatostatin receptor subtype 2 ligand (Tyr3)octreotate. These novel conjugates were radiolabeled with copper-64 and subjected to a detailed in vitro and in vivo radiopharmacological characterization. Overall, the results of this study provide an incentive for further investigations of albumin binders for applications in endoradionuclide therapies.

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.

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.

Human-machine sense of agency

Technological advances have resulted in highly automated systems increasing in number and popularity. However, the overarching issue continues to relate to how much autonomy to give to automation and whether it could degrade the human perception of control, which is referred to as Sense of Agency. When present, the operator will be aware that their actions will lead to a certain outcome, which in turn will improve the performance over the task. Furthermore, when Sense of Agency is present, the individuals underestimate the interval between their own actions and their outcomes. This effect, known as Intentional Binding, could provide feedback regarding the effect of both automation and mental workload in Human-Machine Interaction (HMI). The objective of this paper was to find out how Intentional Binding is affected by different levels of automation, mental workload, and time delay. Intentional Binding has been measured by using a time interval estimation task. Participants were asked to reproduce the time interval between a keypress and an acoustic tone presented with different time delays (500 to 1500 ms). Automation was manipulated at the time of the initial key press to create three conditions: a) Human Decision (keypress performed by the participants), b) System Warning (computer warned the participants to press a key), c) System Decision (keypress virtually performed by the computer). The mental workload was manipulated by adding a secondary memory task, with two or eight letters to remember. Results showed that Intentional Binding was greatest with decreasing automation intervention and mental workload. These findings suggest that automation and mental workload could play a key role in degrading the Sense of Agency. Further, the time delay was shown to have different effects on each automation condition. This new finding indicates that the time delay could be an important feature in HMI and needs to be carefully designed in automated systems.