The time course of intentional binding

Stimuli caused by actions (i.e., effects) are perceived earlier than stimuli not caused by actions. This phenomenon is termed intentional binding (IB) and serves as implicit measure of sense of agency. We investigated the influence of effect delay and temporal predictability on IB, operationalized as the bias to perceive the effect as temporally shifted toward the action. For short delays, IB increased with delay (Experiment 1: 200 ms, 250 ms, 300 ms). The initial increase declined for longer delays (Experiment 2: 100 ms, 250 ms, 400 ms). This extends previous findings showing IB to decrease with increasing delays for delay ranges of 250 ms to 650 ms. Further, the hypothesis that IB, that is, sense of agency, might be maximal for different delays depending on the specific characteristics and context of action and effect, has important implications for human-machine interfaces.     

Intentional binding of visual effects

When an action produces an effect, the effect is perceived earlier in time compared to a stimulus without preceding action. This temporal bias is called intentional binding (IB) and serves as an implicit measure of sense of agency. Typically, IB is investigated by presenting a rotating clock hand while participants execute an action and perceive a resulting tone. Participants are asked to estimate the time point of tone onset by referring to the clock hand position. This time point estimate is compared to a time point estimate of a tone in a condition in which the tone occurs without preceding action. Studies employing this classic clock paradigm employed auditory action effects. We modified this paradigm to investigate potential IB of visual action effects, and, additionally, to investigate how IB differs for visual action effects (Experiment 1) in comparison to auditory action effects (Experiment 2). Our results show that, like the IB of an auditory effect, the time point of a visual action effect is shifted toward the causing action, and that the size of the IB depends on the delay duration of the effect. Comparable to auditory action effects, earlier action effects showed stronger IB compared to later action effects. Yet overall IB of the visual effects was weaker than IB of the auditory effects. As IB is seen as an indicator of sense of agency, this may have important implications for the design of human-machine interfaces.