Am I the same person across my life span? An event-related brain potentials study of the temporal perspective in self-identity.

Abstract

While self-identity recognition has been largely explored, less is known on how self-identity changes as a function of time. The present work aims to explore the influence of the temporal perspective on self-identity by studying event-related brain potentials (ERP) associated with face processing. To this purpose, participants had to perform a recognition task in two blocks with different task demands: (i) identity recognition (self, close-friend, unknown), and (ii) life stage recognition (adulthood -current-, adolescence, and childhood). The results showed that the N170 component was sensitive to changes in the global face configuration when comparing adulthood with other life stages. The N250 was the earliest neural marker discriminating self from other identities and may be related to a preferential deployment of attentional resources to recognize own face. The P3 was a robust index of self-specificity, reflecting stimulus categorization and presumably adding an emotional value. The results of interest emerged for the subsequent late positive complex (LPC). The larger amplitude for the LPC to the self-face was probably associated with further personal significance. The LPC, therefore, was able to distinguish the continuity of the self over time (i.e., between current self and past selves). Likewise, this component also could discriminate, at each life stage, the self-identity from other identities (e.g., between past self and past close-friend). This would confirm a remarkable role of the LPC reflecting higher self-relevance processes. Taken together, the neural representation of oneself (i.e., "I am myself") seems to be stable and also updated across time.