Conceptual representations are perceptually grounded, but when investigating which perceptual modalities are
involved, researchers have typically restricted their consideration to vision, touch, hearing, taste, and smell. However,
there is another major modality of perceptual information that is distinct from these traditional five senses; that is,
interoception, or sensations inside the body. In this paper, we use megastudy data (modality-specific ratings of
perceptual strength for over 32,000 words) to explore how interoceptive information contributes to the perceptual
grounding of abstract and concrete concepts. We report how interoceptive strength captures a distinct form of
perceptual experience across the abstract-concrete spectrum, but is markedly more important to abstract concepts
(e.g., hungry, serenity) than to concrete concepts (e.g., capacity, rainy). In particular, interoception dominates
emotion concepts, especially negative emotions relating to fear and sadness, moreso than other concepts of equivalent
abstractness and valence. Finally, we examine whether interoceptive strength represents valuable information in
conceptual content by investigating its role in concreteness effects in word recognition, and find that it enhances
semantic facilitation over and above the traditional five sensory modalities. Overall, these findings suggest that
interoception has comparable status to other modalities in contributing to the perceptual grounding of abstract and
concrete concepts.