Negation has historically been associated with paradoxical effects on memory, particularly through the induction of false memories. Recent research, however, has shown that negation can also lead to forgetting. Specifically, responding NO, in contrast to responding YES, has been found to impair memory in subsequent recognition and free recall tasks (Mayo et al., 2014). Despite this emerging evidence, the mechanisms driving negation-induced forgetting remain unclear. One plausible explanation is that it may result from associative interference, akin to the fan effect (Radvansky et al., 2017). This interference likely arises because negation imposes greater semantic complexity than affirmation, as it requires the mental representation of both the negated scenario and its alternative. For example, in one study, after learning from a video that an ashtray was empty, participants responded NO to statements like “The ashtray was full” and YES to statements like “The ashtray was empty”. As a result, the word “ashtray” was less likely to be remembered after NO than YES responses, likely because the former involved an additional scenario for the same object. This communication will present our most recent findings using two novel memory paradigms designed to match the semantic complexity of YES and NO responses. The findings demonstrate that, although associative interference may have played a role in previous studies, negation—whether as a response or as a lexical element in a statement—consistently leads to greater forgetting than affirmation. Based on these results, we will also explore potential mechanisms underlying the long-term effect of negation on memory.