Indirect experiential grounding: semantic similarity of abstract scientific concepts is reflected in activity patterns in visual and motor cortex.

Grounded cognition theories propose that interactions with situations establish experiential memory traces that constitute conceptual meaning. However, as abstract scientific concepts are frequently learned through language, a proposed indirect grounding mechanism postulates that modal representations are extrapolated from distributional language-based representations, which are themselves mapped onto existing modal representations. Using functional magnetic resonance imaging (n = 51), we tested the mapping of distributed language representations on modal representations by asking whether semantic similarity of distributional language representations of scientific concepts corresponds to the similarity of neural activation patterns in modal brain systems. Semantic similarity based on both distributed language representations and experiential features was reflected in the multi-voxel activity pattern within occipital and fronto-parietal cortex, overlapping with activation induced by real visual perception and hand action, in addition to multimodal areas outside the brain regions sensitive to perception or action. Although its functional relevance for extrapolating modal representations remains to be determined, this mapping between language and the visuo-motor system is a fundamental element of the indirect grounding mechanism. This mechanism provides sensory-motor experience for the unseen and enriches knowledge for concepts learned exclusively from language.