Intentional Binding is independent of the validity of the action effect's identity

You do you: susceptibility of temporal binding to self-relevance

The self-prioritization effect suggests that self-relevant information has a processing advantage over information that is not directly associated with the self. In consequence, reaction times are faster and accuracy rates higher when reacting to self-associated stimuli rather than to other-related stimuli (Sui et al., Journal of Experimental Psychology: Human Perception and Performance 38:1105-1117, 2012). This spurs the assumption that self-associated action-effects should also be perceived earlier than other-related outcomes. One way to measure this is temporal binding. Previous research indeed showed that the perceived temporal interval between actions and self-associated outcomes was reduced compared to friend- and other-associated outcomes. However, the employed method (interval estimations) and several experimental design choices make it impossible to discern whether the perceived shortening of the interval between a keypress and a self-relevant outcome is due to a perceptual shift of the action or of the action-effect or both. Thus, we conducted four experiments to assess whether temporal binding can indeed be modulated by self-relevance and if so where this perceptual bias is located. The results did not support stronger temporal binding for self- vs other-related action-effects. We discuss these results against the backdrop of the attentional basis of self-prioritization and propose directions for future research.

Action-outcome delays modulate the temporal expansion of intended outcomes

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

I am not the cause of this pain: An experimental study of the cognitive processes underlying causal attribution in the unpredictable situation whether negative outcomes

OBJECTIVES

Pain causal attribution is the attribution of pain causes to self or others, which may depend on one's choice of actions. The study aimed to examine how the cognitive processes of pain causal attribution as one aspect of the sense of agency change in healthy individuals based on free or forced choice, using a temporal binding (TB) experimental task.

METHODS

Participants pressed keys (action) in a combined TB task, with one key having a high probability of delivering pain (with tone). In fact, only the bias between the free-choice and the forced choice conditions was manipulated. Participants estimated the time between their action and tone, with shorter intervals indicating internal attribution.

RESULTS

Interval estimation was significantly longer in the forced-choice condition than in the free-choice condition when a pain stimulus was delivered.

CONCLUSIONS

Explicit complaints of pain being caused by others may be represented in implicit cognitive processes.

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.

The pursuit of the end: The effects of action-goal choices on temporal binding

The effect of action choice (whether one can choose their actions freely) on temporal binding (TB), the temporal contraction between a voluntary action and its effect, is controversial. The present study tried to distinguish action-goal choice (whether one could pursue the action-effect freely) from action choice. Experiments 1 and 2 focused on the effect of action-goal choice on TB while the congruency between actions and outcomes was manipulated (i.e., 50% in Experiment 1 and 80% in Experiment 2). Experiment 3 investigated the effect of action choice on TB when the outcome congruency was 80%. Results showed that free and instructed action-goals led to comparable magnitudes of TB while free actions led to a larger TB than instructed actions. Furthermore, the effect of outcome congruency on TB varied by action-goal choices (Experiment 2) but not action choices (Experiment 3). These results demonstrate the potential differences between action choice and action-goal choice.

What over When in causal agency: Causal experience prioritizes outcome prediction over temporal priority

Prior expectations strongly structure the way we perceive the world and ourselves. For instance, action-outcome prediction can modulate time perception and causal experience. We designed a study that allowed us to investigate whether action-outcome prediction has similar effects on time perception and intentional causality. Participants viewed a stimulus that was consistent or inconsistent with the action they, or another agent executed. The stimulus preceded or followed these actions and participants reported simultaneity or causal judgments. Observers were more likely to report the consistent outcomes as being generated by the action, even when the outcomes actually preceded the action. However, outcome consistency did not modulate simultaneity judgments. These results shed insight on the relationship between time and causal experience. It suggests that time perception and causal experience do not rely in the same way on temporal information, the latter being more permeable to contextual cues such as action-outcome consistency.

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.

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.

Sense of Agency in Multi-Step Actions

In our daily lives, we frequently execute actions that require several steps to bring about the outcome. However, investigations on how the sense of agency—the sense of controlling our actions and their outcomes—evolves in multi-step actions are still lacking. The purpose of the present research is to fill this gap. In the present study, the participants executed one-step, two-step, and three-step actions in which one, two, or three keys had to be pressed consecutively to generate a tone. We used sensory attenuation as an implicit measure of the sense of agency. Sensory attenuation means that self-produced sensory effects are perceived as less intense than externally generated effects. In the present experiment, sensory attenuation was measured in a psychophysical paradigm and increased in multi-step actions compared to the one-step action. We also asked the participants to explicitly rate the amount to which they felt that they had generated the tone. Ratings were highest in the one-step condition and dropped for multi-step actions, thus showing the opposite pattern of the sensory attenuation data. We assume that enhanced sensory attenuation in multi-step actions could be due to increased effort or more accurate sensorimotor predictions of action effects. The decrease in explicit ratings for multi-step actions might be attributed to reduced perception of causality.

Time for Action: Verbal Action Cues Influence Temporal Binding

Prior research has shown that our perception of time is compressed when we volitionally perform actions, a phenomenon referred to as temporal binding. In three studies, we investigated the degree to which contextual cues that signaled other agents and related to actions would influence binding, given that those cues may affect individual's feelings of independent action performance. Participants heard action verbalizations that did or did not match actions that participants had already begun performing. Participants' time estimates of the intervals between action initiations and action effects were higher on trials in which they heard verbalizations that matched their ongoing actions, and lower on trials in which the verbalizations and actions did not match. Such effects did not occur when participants passively observed actions and effects being caused by the computer. These results show that the compatibility of action cues with ongoing actions influences temporal binding effects, suggesting that they influence our feelings of having been an independent agent.

Context-induced contrast and assimilation effects in explicit and implicit measures of agency

Virtual-hand-illusion studies often use explicit and implicit measures of body ownership but no agreed-on implicit measure of agency exists. We investigated whether the Intentional Binding (IB) effect could serve as such a measure. A pilot study confirmed that current consistency increases both perceived agency and IB. In three experiments, current consistency was 50% but the previously experienced consistency was either 100% or 0%. When previous and present consistency experience were separated by a short break, both explicit judgments and IB showed a contrast effect. Eliminating the break reversed the effect in explicit agency but not in IB; and making the transition between previous and present consistency smoother replicated the effect for explicit agency but reversed the pattern for IB. Our findings suggest that explicit agency and IB rely on different sources of information, presumably including cross-sensory correlations, predictions of expected action-effects, and comparisons between present and previous consistency experiences.

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.

Action Choice and Outcome Congruency Independently Affect Intentional Binding and Feeling of Control Judgments

Sense of agency (SoA) refers to the subjective experience that one is in control of their actions and the consequences of these actions. The SoA is a complex phenomenon, influenced by a weighted combination of various prospective (pre-movement) and retrospective (post-movement) processes and factors related to action choice, action selection fluency, action-outcome associations and higher-level inferences. In the current study, we examined the effect of the congruency between actions and outcomes in a context where the choice-level of actions was varied from 1 to 4. The actions consisted of right, left, up and down key presses while the outcomes were visual representations of the actions (i.e., right, left, up and down-pointing arrowheads). Participants performed either an instructed action or freely selected an action among two, three, or four alternatives. Each action randomly produced either a congruent or an incongruent outcome, depending on the matching between the direction of the key press and the direction of the outcome arrowhead. Participants estimated the delay between their actions and the observed outcomes and reported their feeling of control (FoC) over the outcomes. Interval estimations were used as an indirect measure of the SoA to quantify the intentional binding effect, which refers to the perceived temporal attraction between voluntary actions and their outcomes. The results showed that both intentional binding and FoC were enhanced as the choice-level was increased from 1 to 4. Additionally, intentional binding and FoC over the outcomes were stronger when actions produced congruent compared to incongruent outcomes. These results provide additional evidence that both intentional binding and FoC are sensitive to the number of action alternatives and the congruency between actions and their outcomes. Importantly, the current study suggests that these prospective and retrospective cues might independently influence intentional binding and FoC judgments.

The influence of action-effect anticipation on bistable perception: differences between onset rivalry and ambiguous motion

Perception is strongly shaped by the actions we perform. According to the theory of event coding, and forward models of motor control, goal-directed action preparation activates representations of desired effects. These expectations about the precise stimulus identity of one's action-outcomes (i.e. identity predictions) are thought to selectively influence perceptual processing of action-contingent effects. However, the existing evidence for such identity-prediction effects is scarce and mixed. Here, we developed a new paradigm to capture such effects and examined whether action-outcome predictions can bias the perception of binocular onset rivalry (Experiments 1a and 1b) and bistable motion (Experiment 2). Participants performed learning tasks in which they were exposed to action-outcome associations. On test trials, actions were followed by bistable stimuli that could be perceived as being either congruent or incongruent with the aforementioned associations (i.e. rivalrous oriented gratings in Experiments 1a and 1b and spheres with ambiguous rotation directions in Experiment 2). Across three experiments, we show that, whilst exposure to action-effect associations can bias the apparent motion direction of ambiguous spheres, it fails to influence perceptual selection of grating orientations in binocular onset rivalry. This pattern of results extends previous work on ambiguous motion by demonstrating that action-induced modulations do not generalize to all types of bistable percepts.

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.

Intentional binding of two effects

An action that produced an effect is perceived later in time compared to an action that did not produce an effect. Likewise, the effect of an action is perceived earlier in time compared to a stimulus that was not produced by an action. Despite numerous studies on this phenomenon-referred to as Intentional Binding effect (IB)-the underlying mechanisms are still not fully understood. Typically, IB is investigated in settings where the action produces just one single effect, whereas in everyday action contexts, it rather causes a sequence of effects before leading to the desired outcome. Therefore, we investigated IB of two consecutive effects. We observed substantially more IB of a first effect tone compared to a second tone. This pattern was observed for second tones that were temporally predictable (Exp. 1) or not (Exp. 2 and 3). Interestingly, the second tone yielded stronger IB when it was less delayed (Exp. 4). Thus, also an event occurring later in an unfolding action-effect sequence can be bound to its causing action, but it might be less bound to the action than a first effect. Instead of the fact that it is the second of two consecutive effects, this, however, rather seems to be influenced by the longer delay of a second and, therefore, later occurring effect.

Anticipation of delayed action-effects: learning when an effect occurs, without knowing what this effect will be

According to the ideomotor principle, behavior is controlled via a retrieval of the sensory consequences that will follow from the respective movement ("action-effects"). These consequences include not only what will happen, but also when something will happen. In fact, recollecting the temporal duration between response and effect takes time and prolongs the initiation of the response. We investigated the associative structure of action-effect learning with delayed effects and asked whether participants acquire integrated action-time-effect episodes that comprise a compound of all three elements or whether they acquire separate traces that connect actions to the time until an effect occurs and actions to the effects that follow them. In three experiments, results showed that participants retrieve temporal intervals that follow from their actions even when the identity of the effect could not be learned. Furthermore, retrieval of temporal intervals in isolation was not inferior to retrieval of temporal intervals that were consistently followed by predictable action-effects. More specifically, when tested under extinction, retrieval of action-time and action-identity associations seems to compete against each other, similar to overshadowing effects reported for stimulus-response conditioning. Together, these results suggest that people anticipate when the consequences of their action will occur, independently from what the consequences will be.

Action-outcome learning and prediction shape the window of simultaneity of audiovisual outcomes

To form a coherent representation of the objects around us, the brain must group the different sensory features composing these objects. Here, we investigated whether actions contribute in this grouping process. In particular, we assessed whether action-outcome learning and prediction contribute to audiovisual temporal binding. Participants were presented with two audiovisual pairs: one pair was triggered by a left action, and the other by a right action. In a later test phase, the audio and visual components of these pairs were presented at different onset times. Participants judged whether they were simultaneous or not. To assess the role of action-outcome prediction on audiovisual simultaneity, each action triggered either the same audiovisual pair as in the learning phase ('predicted' pair), or the pair that had previously been associated with the other action ('unpredicted' pair). We found the time window within which auditory and visual events appeared simultaneous increased for predicted compared to unpredicted pairs. However, no change in audiovisual simultaneity was observed when audiovisual pairs followed visual cues, rather than voluntary actions. This suggests that only action-outcome learning promotes temporal grouping of audio and visual effects. In a second experiment we observed that changes in audiovisual simultaneity do not only depend on our ability to predict what outcomes our actions generate, but also on learning the delay between the action and the multisensory outcome. When participants learned that the delay between action and audiovisual pair was variable, the window of audiovisual simultaneity for predicted pairs increased, relative to a fixed action-outcome pair delay. This suggests that participants learn action-based predictions of audiovisual outcome, and adapt their temporal perception of outcome events based on such predictions.

How action structures time: About the perceived temporal order of action and predicted outcomes

Few ideas are as inexorable as the arrow of causation: causes must precede their effects. Explicit or implicit knowledge about this causal order permits humans and other animals to predict and control events in order to produce desired outcomes. The sense of agency is deeply linked with representation of causation, since it involves the experience of a self-capable of acting on the world. Since causes must precede effects, the perceived temporal order of our actions and subsequent events should be relevant to the sense of agency. The present study investigated whether the ability to predict the outcome of an action would impose the classical cause-precedes-outcome pattern on temporal order judgements. Participants indicated whether a visual stimulus (dots moving upward or downward) was presented either before or after voluntary actions of the left or right hand. Crucially, the dot motion could be either congruent or incongruent with an operant association between hand and motion direction learned in a previous learning phase. When the visual outcome of voluntary action was congruent with previous learning, the motion onset was more often perceived as occurring after the action, compared to when the outcome was incongruent. This suggests that the prediction of specific sensory outcomes restructures our perception of timing of action and sensory events, inducing the experience that congruent effects occur after participants' actions. Interestingly, this bias to perceive events according to the temporal order of cause and outcome disappeared when participants knew that motion directions were automatically generated by the computer. This suggests that the reorganisation of time perception imposed by associative learning depends on participants' causal beliefs.

Believing and perceiving: authorship belief modulates sensory attenuation

Sensory attenuation refers to the observation that self-generated stimuli are attenuated, both in terms of their phenomenology and their cortical response compared to the same stimuli when generated externally. Accordingly, it has been assumed that sensory attenuation might help individuals to determine whether a sensory event was caused by themselves or not. In the present study, we investigated whether this dependency is reciprocal, namely whether sensory attenuation is modulated by prior beliefs of authorship. Participants had to judge the loudness of auditory effects that they believed were either self-generated or triggered by another person. However, in reality, the sounds were always triggered by the participants' actions. Participants perceived the tones' loudness attenuated when they believed that the sounds were self-generated compared to when they believed that they were generated by another person. Sensory attenuation is considered to contribute to the emergence of people's belief of authorship. Our results suggest that sensory attenuation is also a consequence of prior belief about the causal link between an action and a sensory change in the environment.