Long-term semantic priming of propositions representing general knowledge

Six experiments investigated semantic priming of individual propositions that reflect common knowledge. Participants performed a sentence-completion task in which each sentence expressed a single proposition, and the same or similar proposition was expressed in prime-target sentence pairs that shared no words. The primary goal was to evaluate the degree to which long-lasting facilitation in primed target sentences reflected memory for abstract proposition meaning versus memory for the operations used to construct proposition meaning and select a response. Priming effects persisted over delays exceeding 15 min, were not attributable to explicit memory processes, did not depend on either repeated syntactic structure or response decision, and were greater than facilitation attributable to priming individual word meanings. In total, the evidence provides initial support for operation-independent, long-term semantic priming of propositions outside the context of connected discourse. This extends the empirical evidence for long-lasting facilitation that theories of semantic priming must explain.