Jie Zheng¹, Sami R. Yousif¹, Brynn E. Sherman¹; ¹The Ohio State University

The information we encounter in our environments is seldom novel: Virtually everything that we see is a variation of something that we’ve seen before. That existing knowledge can powerfully shape the way we process and encode new experiences into memory. For instance, a familiar chess position might be easier to remember than an unfamiliar one. Yet our memories can also be influenced by intrinsic properties of the stimuli themselves. That is, some stimuli are more memorable than others; some images are consistently remembered or forgotten across people. But how does intrinsic memorability interact with an individual’s existing, idiosyncratic knowledge of the world? Here, we explored this question using a stimulus set for which people have a wide range of existing knowledge: Pokémon. Specifically, we had two groups of participants perform a simple encoding task with Pokémon images, followed by a recognition memory task. One group of participants had existing knowledge of Pokémon (Familiar group), and one group had no such knowledge (Unfamiliar group). Across two experiments using different image sets, we found that memorability was shaped by existing knowledge. Despite having worse memory overall, participants in the Unfamiliar group were more reliable in their memories, in the sense that there was greater consistency in which images were memorable (hit rate) and which were familiar (false alarm rate). The relatively lower consistency in the Familiar group may suggest that existing knowledge causes memories to become more idiosyncratic, leading to greater variability within the population. In other words, while increased knowledge may improve memory overall, it may also make some memories more distinctive to individuals, partially counteracting the impact of intrinsic memorability in driving consistent memory across people.