Time perception and the experience of agency

In the current study, we investigate whether sense of agency over an effect coincides with the perceived time of the effect that occurs either at its usual time or earlier or later than usual. One group of participants usually perceived an action effect immediately after the action, another group delayed by 250 ms. In test blocks the effect stimulus was sometimes presented earlier or later than usual. Participants judged either the degree of experienced agency over the effect or whether the effect had appeared at its usual time, or earlier or later than usual. In both groups experienced agency and the perception of the effect’s time ‘as usual’ were highly correlated. To rule out that time judgments influenced sense of agency, we replicated the pattern of agency judgments in Experiment 2 in which participants only judged agency. Taken together, we demonstrated that agency and time judgments vary similarly across temporal deviations of effects irrespective of to which delay participants were adapted to. The high correlation of judgment types indicates that perceiving an effect at its usual time and sensing to have caused the effect are closely related. In contrast, physical temporal proximity of actions and effects has only a minor impact on experienced agency.     

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

When an action produces an effect, both events are perceived to be shifted in time toward each other. This shift is called Intentional Binding (IB) effect. First evidence shows that this shift does not depend on the statistical predictability of the produced effect's identity (Desantis, Hughes, & Waszak, 2012). We confirm this result by comparing the perceived duration of action–effect intervals before valid and invalid action effects using the method of constant stimuli. The perceived duration of action–effect intervals did not differ for valid and invalid effects. This result was true for different durations of the action–effect interval (Experiments 1–4: 250 ms, Experiments 1 & 2: 400 ms), different effect modalities (Experiments 1 & 3: visual, Experiments 2–4: auditive), and two types of validity variations (Experiments 1 & 2: 80% valid, Experiments 3 & 4: 100% valid vs. random). We validated our results by using a clock paradigm and a numerical duration estimation task (Experiment 4). We conclude that the IB effect is not the result of internal prediction due to action–effect bindings, but might rely on higher-order processes.     

Adaptive control of ideomotor effect anticipations

According to ideomotor theory, voluntary actions are selected and initiated by means of anticipated action effects. Prior experiments yielded evidence for these effect anticipations with response-effect (R-E) compatibility phenomena using blocked R-E relations. Daily actions, however, typically evoke different effects depending on the situational context. In the present study, we accounted for this natural variability and investigated R-E compatibility effects by a trial-by-trial variation of R-E compatibility relations. In line with recent observations regarding ideomotor learning, R-E compatibility influenced responding only when participants responded in free choice trials assuming that participants then adopted an intention-based action control mode. In contrast, R-E compatibility had no impact when participants responded according to imperative stimuli throughout the experiment, thus when participants adopted a stimulus-based action control mode. Interestingly, once an intention-based mode was established because of free choice trials within an experimental block, we observed response compatibility effects in free as well as forced choice trials. These findings extend and refine theoretical assumptions on different action control modes in goal-directed behavior and the specific contribution of ideomotor processes to intention-based action control.