Scrutinizing the grey areas of declarative memory: Do the self-reference and temporal orientation of a trait knowledge task modulate the Late Positive Component (LPC)?

Knowledge about the future self may engage cognitive processes typically ascribed to episodic memory, such as awareness of the future self as an extension of the current self (i.e., autonoetic awareness) and the construction of future events. In a prior study (Tanguay et al., 2018), temporal orientation influenced the Late Positive Component (LPC), an ERP correlate of recollection. The LPC amplitude for present traits was intermediate between semantic and episodic memory, whereas thinking about one's future traits produced a larger LPC amplitude that was similar to episodic memory. Here, we examined further the effect of temporal orientation on the LPC amplitude and investigated if it was influenced by whether knowledge concerns the self or another person, with the proximity of the other being considered. Participants verified whether traits (e.g., Enthusiastic) were true of themselves and the "other," both now and in the future. Proximity of the other person was manipulated between subjects, such that participants either thought about the typical traits of a close friend (n = 31), or those of their age group more broadly (n = 35). Self-reference and temporal orientation interacted: The LPC amplitude for future knowledge was larger than for present knowledge, but only for the self. This effect of temporal orientation was not observed when participants thought about the traits of other people. The proximity of the other person did not modify these effects. Future-oriented cognition can engage different cognitive processes depending on self-reference; knowledge about the personal future increased the LPC amplitude unlike thinking about the future of other people. Our findings strengthen the notion of self-knowledge as a grey area between semantic and episodic memory.