A common neural axis links image distinctiveness and memorability

Stimulus-specific memorability, the tendency for people to remember and forget the same stimuli, is a powerful predictor of memory performance that is independent of the study and retrieval factors that have dominated memory research. Critically, memorability can be defined in two ways: "Hit-ability" (H-ability) and "false alarm-ability" (FA-ability), the probability of correctly recognizing studied items or falsely recognizing unstudied items, respectively. Although past work has suggested that these are dissociable facets of memorability, challenging single-factor explanations, we present neural and computational evidence that they share a common neural axis. The neural signature of high H-ability matched the signature for low FA-ability, showing that these parameters have inverse relationships with a common factor. Moreover, we show that image distinctiveness predicts the flipped relationship between H-ability and FA-ability in both behavior and neural activity, providing a unifying explanation of stimulus-specific memorability.