Cortical reinstatement of causally related events sparks narrative insights by updating neural representation patterns

We make sense of everyday events by reasoning about their underlying causes. When we connect causal links between events separated in time, we often experience a sudden feeling of “aha!”, or insight. To understand its cognitive and neural mechanisms, we designed an fMRI study in which participants watched a temporally scrambled TV episode. Participants pressed an “aha” button whenever they understood something new and explained their reasoning. More than 40% of insight explanations reference past events causally related to the current event. Neural patterns representing these causally related past events are reinstated across the cortex. This neural reinstatement drives sudden shifts in cortical activity patterns ~2 s prior to aha button presses, reflecting updates in situational representation. Moreover, distributed brain areas represent causally related events with similar neural patterns, beyond shared semantic or perceptual features. Together, the study suggests that we comprehend events by retrieving causally related past events, followed by updating neural patterns at moments of insight.