Mood congruent memory in depressive states has been considered a robust effect (Blaney,1986), but findings have been somewhat equivocal. One possible reason is that commonly used choice reaction time tasks are especially sensitive to individual differences in response biases, which can add variability and obscure true differences. The diffusion model (Ratcliff, 1978) incorporates all aspects of the behavioral data from these tasks to separate the components of processing and control for response biases. We applied the diffusion model to data from lexical decision and recognition memory tasks and showed strong support for mood congruent memory: nondysphoric subjects had a better memory match for positively than negatively valenced words, but dysphoric subjects had no difference. This pattern was not apparent in the traditional analyses of reaction times or accuracy. Implications for using the diffusion model to better understand data from choice reaction time tasks are discussed. |