The irrelevance of distributional assumptions on reaction times in multidimensional scaling of same/different judgment tasks

Abstract

Takane and Sergent developed a model (MAXRT) for scaling same/different judgments and response times (RTs) simultaneously. The model assumes that RTs are distributed lognormally. Our experiment showed that the RT distribution of the judgments might be task dependent. It is shown that lognormal RTs provide a far better fit than exponential, normal, and Pareto distributed RTs (with the same means and variances), but that the final parameter estimates from the data set with lognormal RTs hardly differ from the alternatively distributed RTs. Finally, despite the robustness of the distributional assumption of the RTs with respect to the parameter estimates, it is shown that RTs have an informational value that is not contained in the same/different judgments alone.