Temporal-experiential distance in virtual reality shapes past and future episodic simulations and simulation-induced forgetting.

This study investigates the shared constructive processes involved in past- and future-oriented episodic simulations, defined as mentally generating detailed, context-specific events, and examines how temporal-experiential distance shapes these simulations in virtual reality (VR). Young adults used a VR "time machine" that placed them in four temporally cued environments (1980, 2020, 2024, 2060). The near-past and near-future contexts (2020, 2024) fell within participants' current autobiographical lifetime and ongoing personal goals (experiential), whereas the distant-past and distant-future contexts (1980, 2060) did not (non-experiential). In each context, participants followed instructions to recall or imagine a specific personal event set in that time period, thereby generating a self-involving episodic simulation. In Experiment 1, episodicity (indexed by specificity, contextual anchoring, and phenomenological richness) decreased with increasing temporal-experiential distance in a similar way for past- and future-oriented simulations. In Experiment 2, participants first encoded objects from semantic categories in a virtual museum and then generated near or distant past- or future-oriented episodic simulations that concerned half of these categories. A simulation-induced forgetting effect (reduced recall for simulated vs non-simulated categories) emerged only for near, experiential contexts. These findings support the existence of a shared episodic simulation mechanism for past and future thought, modulated by the influence of temporal-experiential distance, and highlight VR time machines as ecologically oriented, experimentally controlled tools for studying episodic simulation.