Neural processing of self-produced and externally generated events in 3-month-old infants.

Did I make that sound? Differentiating whether sensory events are caused by us or the environment is pivotal for our sense of agency. Adults can predict the sensory effects of their actions, which results in attenuated processing of self-produced events compared with externally generated events. Yet, little is known about whether young infants predict and discriminate self-produced events from externally produced events. Using electroencephalography (EEG), 3-month-olds' neural response to the same audiovisual stimulus was compared between a Self-produced condition and externally generated conditions with predictable timing (External-Regular) and irregular timing (External-Irregular). We hypothesized that if 3-month-olds predict self-produced events, their event-related potentials should be smallest for the Self-produced condition, strongest for the External-Irregular condition, and in between for the External-Regular condition. Cluster-based permutation tests indicated a more positive deflection (300-470 ms) for irregular stimuli compared with regular stimuli over the vertex. Contrasting the Self-produced and External-Irregular conditions showed a statistical trend within the same time window. Although not fully conclusive, this might suggest the emerging differentiation between self-produced and less predictable external events. However, there was no statistical evidence that infants differentiated self-produced events from temporally predictable external events. Our findings shed light on the emerging sense of agency and suggest that 3-month-olds are transitioning toward predicting and discriminating the consequences of their actions.