No evidence in favour of the existence of 'intentional' binding
Intentional binding refers to the subjective temporal compression between a voluntary action and its sensory outcome. Despite some studies having challenged the link between temporal compression and intentional action, the intentional binding is still widely used as an implicit measure for the sense of agency. The debate remains unsettled primarily because the experimental conditions used in previous studies were confounded with various alternative causes for temporal compression, and action intention has not yet been tested comprehensively against all potential alternative causes in a single study. Here, we solve this puzzle by jointly comparing participants estimates of the interval between three types of triggering events with comparable predictability - voluntary movement, passive movement, external sensory event - and an external sensory outcome (auditory or visual across experiments). Results failed to show intentional binding, i.e., no shorter interval estimation for the voluntary than the passive movement conditions. Instead, we observed temporal (but not intentional) binding when comparing both movement conditions to the external sensory condition. Thus, temporal binding seems to originate from sensory integration and temporal prediction, not from action intention. As such, these findings underscore the need to reconsider the use of "intentional binding" as a reliable proxy of the sense of agency. Public Significance StatementWhen we press a light switch and observe a bulb lightening, we experience a sense of agency, a feeling of control over these events. We also estimate the temporal interval between our voluntary action and its consequence shorter than the same interval between two events in which we are not involved. Such temporal binding has thus been taken as a measure of the sense of agency. However, our study reveals that voluntary actions are neither necessary, nor sufficient for temporal binding. Instead, temporal binding relies on predicting and integrating information. The sense of agency can be disturbed in various psychiatric disorders and its brain mechanisms are currently actively explored. Our study urges amending how it is measured.