Memorability as an Emergent Property: How Representational Structure Creates Apparent Intrinsic Effects

Some pictures, videos, faces, voices, and words are reliably remembered better than others, a phenomenon known as memorability. This has been widely interpreted as reflecting a stable, intrinsic property of the stimuli themselves. Here we argue that this consistency is better explained by the relational structure of the stimulus sets used to measure memorability, rather than as an intrinsic property of the items. Using simulations with a global matching model of recognition memory, we show that apparent intrinsic memorability emerges naturally from distinctiveness — how dissimilar an item is from others in a given set of encoded images — without any stimulus-intrinsic mechanism. In behavioral experiments, we demonstrate that manipulating the similarity structure of image sets can invert memorability rankings, making previously memorable images forgettable and vice versa. We also show that features previously identified as intrinsically memorable (such as “body-part related”) are the most representationally distinctive features in standard databases, explaining their memorability. To address these large variations in distinctiveness we created a new image set that reduced variability in representational distinctiveness, and found it significantly diminishes all feature-memorability relationships. These findings suggest that memorability is not a fixed attribute of items themselves, but an emergent property of which items are distinctive within the context, with implications for how we attribute stable psychological properties to stimuli more broadly.