Benjamin Johnson¹, Dyllan Simpson¹, Timothy Brady¹; ¹University of California San Diego

Recognition memory is typically enhanced by expertise. Chess masters better remember chess positions and radiologists better remember mammograms. However, in some contexts, expertise appears to impair memory through increased source confusion. For instance, when asked to recall a subset of NFL teams, football experts are more likely than novices to falsely "remember" unstudied teams (Castel et al., 2007). Does this reflect a genuine cost of expertise? In our first experiment, we tested recognition memory for sports logos in NFL and NHL fans, comparing experts remembering logos from their domain of expertise versus outside their expertise. We replicated previous results showing increased false alarm rates on logos within participants’ domain of expertise. However, in strong contrast to previous findings, we show this does not reflect a genuine memory impairment. ROC analyses revealed only a criterion shift: experts showed the same memory strength for items in and outside their domain but struggled to distinguish whether their sense of familiarity came from the experiment prior exposure. This led to more 'old' responses for both studied and unstudied logos in their domain of expertise. Our second experiment used novel game photos instead of logos. Here, experts demonstrated better recognition memory for photos from their domain of expertise. Unlike logos, these game photos were less familiar, reducing source memory interference while still allowing experts to leverage their domain knowledge. These findings reveal that expertise effects on recognition memory depend critically on stimulus familiarity. While expertise provides no advantage for highly familiar stimuli due to source confusion, it enhances memory for novel domain-relevant materials where prior exposure cannot interfere. Rather than demonstrating a "dark side" of expertise, these results show that controlling for stimulus familiarity eliminates apparent expertise costs, allowing experts to demonstrate their enhanced encoding and retrieval capabilities.