Robust intentional binding for causally-linked sequences of naturalistic events but not for abstract event sequences.

Past studies have shown that when a voluntary action produces a sensory effect, the action and the effect will be perceived as being closer in time. This subjective temporal 'attraction' is known as intentional binding (IB). Induction of IB is dependent on the intentionality of one's actions, the predictability of the effect, and the causality between the action and the effect. Previous investigations of IB have utilized abstract stimuli (e.g., flashes and beeps) with adaptation so as to associate the abstract action-effect link. Yet, events from our everyday experiences already have an inherent action-effect link. We, thus, investigated, for the first time, IB under naturalistic, multisensory stimulation by manipulating the intentionality, predictability, and causal event link. A total of five experiments without adaptation were conducted examining IB with: abstract stimuli (Experiment 1), naturalistic effects (Exp. 2), naturalistic action cue and effect matching (Exp. 3), naturalistic action cue and effect mismatching (Exp. 4), and naturalistic action cue and effect matching but mismatched response mapping (Exp. 5). Analyses of the data showed the absence of IB for abstract stimuli without action-effect adaptation (Exp. 1) and for effects that were not inherently causal or predictable of one's action (Exp. 2, 4, and 5). IB, however, was induced when the naturalistic sequence of action cue-effect was casually linked and predictable in terms of timing (Exp. 3). Overall, our results showed that induction of IB is dependent on the inherent causal and predictable association of an event from the cue to act to the consequence of that action, an association that is already present in everyday multisensory events.