Semantic memory: Distinct neural representations for abstractness and valence

• In an MRI, participants read abstract/concrete words that were emotional or neutral.
• Valenced words activated both concrete and abstract regions throughout the brain.
• The rostral anterior cingulate responded to emotional content but not abstract words.
• Results failed to support the hypothesis that abstract words are inherently valenced.

The hypothesis that abstract words are grounded in emotion has been supported by behavioral research and corpus studies of English words. A recent neuroimaging study reported that a single brain region, the rostral anterior cingulate cortex (rACC), is responsive to abstract words, and is furthermore modulated by the emotional valence. This finding is surprising because the rACC is not commonly associated with semantic processing. It is possible that the effects observed were driven not by abstractness, but rather by valence, since the abstract words used in that study were significantly more emotional than the concrete words. We tested this hypothesis by presenting participants with words that were abstract/concrete, as well as emotionally valenced/neutral in a 2 × 2 factorial design. Activations to emotional words overlapped with both abstract and concrete activations throughout the brain. An ROI analysis revealed that the rACC was responsive to valence, not abstractness, when concreteness and valence unconfounded.