Amnesia Induced by Suppressing the Focus of Internal Attention

Our thoughts can recede as we direct attention to the external world. This experience may reflect the suppression of thoughts about past events, future worries, or stray ideas that could otherwise disrupt focus. Such thoughts may arise spontaneously from replay mechanisms supported by the episodic memory system; hence, sustaining external focus may require suppressing these systems to stop internal distraction. Here, periods of high external focus disrupted diverse episodic content activated near in time, inducing an 'amnesic shadow'. This shadow occurred for both novel content and already formed memories and exhibited key markers of active suppression: forgetting beyond expectations from time alone, which generalised to an alternative reminder. External attention therefore automatically engages an active suppression mechanism that appears to broadly inhibit cognitive systems supporting the emergence of distracting thoughts. The findings raise the possibility that people may naturally gravitate toward activities demanding external attention, unwittingly, to regulate unwanted thoughts.