Episodic details are better remembered in plausible relative to implausible counterfactual simulations

People often engage in episodic counterfactual thinking, or mentally simulating how the experienced past might have been different from how it was. A commonly held view is that mentally simulating alternative event outcomes aids in managing future uncertainty and improving behavior, for which episodic counterfactual simulations need to be remembered. Yet, the phenomenological factors influencing the memorability of counterfactual simulations remain unclear. To investigate this, we conducted two experiments using a paradigm where participants recalled autobiographical memories. After one week, they created counterfactual mental simulations of these memories, integrating a new object into each one and rating them on various phenomenological characteristics. Memory for these counterfactual mental simulations was tested the next day by recalling the new object. Across the two experiments we found that objects included in more plausible counterfactual simulations were better remembered compared to implausible counterfactual simulations. Our findings suggest that generating episodic counterfactual simulations perceived as plausible enhances their memorability, similar to other memory phenomena in which schematic knowledge improves subsequent episodic memory.