Proceedings of the Annual Meeting of the Cognitive Science Society

Many studies on memory retrieval in language processing haveidentified similarity-based interference as a key determinant ofcomprehension. The broad consensus is that similarity-basedinterference reflects erroneous retrieval of a non-target itemthat matches some of the retrieval cues. However, themechanisms responsible for such effects remain debated.Activation-based models of retrieval (e.g., Lewis & Vasishth,2005) claim that any differences in processing difficulty due tointerference in standard RT measures and judgments reflectdifferences in the speed of retrieval (i.e., the amount of time ittakes to retrieve a memory item). But this claim is inconsistentwith empirical data showing that retrieval time is constant dueto the use of a direct-access procedure (e.g., McElree, 2000,2006). According to direct-access accounts, differences injudgments or RTs due to interference arise from differences inthe quality or availability of the candidate memoryrepresentations, rather than differences in retrieval speed. Toadjudicate between these accounts, we employed a novelmethodology that combined a high-powered (N = 200) two-alternative forced-choice study on interference effects withdrift diffusion modeling to disassociate the effects of retrievalspeed and representation quality. Results showed that thepresence of a distractor that matched some of the retrieval cueslowered asymptotic accuracy, reflecting an effect ofrepresentation quality, but did not affect retrieval speed,consistent with a direct-access procedure. These results suggestthat the differences observed in RTs and judgment studiesreflect differences in the ease of integrating the retrieved itemback into the current processing stream, rather than differencesin retrieval speed.