Statistical properties of the speed-accuracy trade-off (SAT) paradigm in sentence processing.

Studies of the speed-accuracy trade-off (SAT) have been influential in arguing for the direct-access model of retrieval in sentence processing. The direct-access model assumes that long-distance dependencies rely on a content-addressable search for the correct representation in memory. Here, we address two important weaknesses in the statistical methods standardly used for analysing SAT data. First, these methods are based on non-hierarchical modelling. We show how a hierarchical model can be fit to SAT data, and we test parameter recovery in this more conservative model. The parameters most relevant to the direct-access account cannot be accurately estimated, and we attribute this to the standard SAT model being overparameterised for the limited data available to fit it. Second, the power properties of SAT studies are unknown. We conduct a power analysis and show that inferences from null results to the null hypothesis, though commonplace in the SAT literature, may be unwarranted.