Memory processes underlying long-term semantic priming.

Two decades of research in semantic priming has provided substantial evidence for a distinction between short- and long-term semantic priming effects. Early models of cognition suggested a single mechanism to explain priming at short and long lags. Later models refuted this explanation and proposed that different mechanisms are necessary to account for different durations of priming effects. Two alternative explanations of long-term semantic priming effects have been proposed in the extant literature. The first explanation is that long-term semantic priming effects rely upon the incremental strengthening of abstract semantic memory representations. The second explanation is that long-term priming is the result of memory for prior cognitive operations. In two experiments, we used different semantic content - word meaning versus category membership - to investigate the mechanisms accountable for long-term semantic priming. Evidence from the two experiments suggests that long-term semantic priming effects are due to different memory processes for different semantic content. Long-term semantic priming of word meanings was dependent on strengthening abstract semantic memory representations and persistent priming of category membership was dependent on memory for prior cognitive operations.