How language represents meaning remains a central topic of debate in linguistics. On some accounts, the noun phrases in a sentence are identified semantically by a list of independent atomic labels (thematic roles), ordered relative to one another depending on the position of the nouns around the verb (e.g., AGENT-THEME-GOAL). Others instead capture such interdependencies with complex, non-atomic event structures (e.g., [x CAUSE [y TO-COME-TO-BE-AT z]]). Here, we use structural priming to investigate the psychological reality of these two theories of semantic representation. On the thematic role approach, we should expect to see priming between theme-first locatives and prepositional-object datives (both VP-NP-PP syntactically) precisely because their thematic ordering is consistent across the two constructions. The event structure approach posits no such minimal semantic structural similarity, such that we should not see priming cross-constructionally. We find only within-construction priming (N=52) and not across-construction priming (total N=344), in favor of event structures.