Composition of event concepts: Evidence for distinct roles for the left and right anterior temporal lobes

Characterizing the precise computations carried out by the various nodes of the semantic network remains a central challenge. One of the better understood nodes within this system is the left anterior temporal lobe (LATL), which shows an early (∼250 ms) amplitude increase if the semantic composition between the current word and its context is in some ways "simple." As this type of effect has only been demonstrated for noun-modifier composition, we asked if a similar pattern is elicited for verb phrase composition. Agentive, resultative, and eventive adverbs were employed to vary whether the meaning of the adverb directly applies to the verb or not, with only eventives exemplifying direct and straightforward composition. Results showed that eventives, but not agentives or resultatives, elicited a significant increase in the LATL at 250 ms. The RATL showed a sharply contrasting pattern, with agentives showing the largest activity, suggesting a distinct role in semantic composition.