The privileged role of conceptual knowledge in episodic memory distortions

Prior knowledge strongly influences memories for new experiences, typically distorting a new experience to better ‘fit’ within our prior conceptions. While conceptual features, like category membership, have long been shown to induce memory distortions, perceptual features of to-be-remembered information, like color, can also distort memories. We investigated whether conceptual and perceptual features of new episodic memories – when in competition – equally contribute to a memory’s distortion, or if there is a hierarchy of featural influence. To do so, we used a spatial learning task that has been shown to induce distortions in new location memories due to the influence of prior knowledge. Image locations were organized by conceptual or perceptual features (e.g., separate clusters of birds and blue things), and some images were placed in locations that conflicted with one or both cluster types (e.g., a raven placed away from most birds, a blueberry placed away from most blue things, a blue jay placed away from both). Memory distortion was measured as the extent that these conflicting images were retrieved closer to their respective cluster locations relative to their encoded locations. We observed that in isolation, both conceptual and perceptual features contribute to memory distortions of equivalent magnitude, but when competing, images were predominantly biased toward their conceptual cluster. This greater conceptual distortion persisted even when changing the encoding task to one that prioritizes processing of perceptual features. These results suggest that conceptual features play a privileged role in the organization of new long-term memories regardless of encoding demands.