A crossed random effects diffusion model for speeded semantic categorization decisions

Joachim Vandekerckhove, Steven Verheyen, Francis Tuerlinckx
2010 Acta Psychologica  
Choice reaction times (RTs) are often used as a proxy measure of typicality in semantic categorization studies. However, other item properties have been linked to choice RTs as well. We apply a tailored process model of choice RT to a speeded semantic categorization task in order to deconfound different sources of variability in RT. Our model is based on a diffusion model of choice RT, extended to include crossed random effects (of items and participants). This model retains the interesting
more » ... ess interpretation of the diffusion model's parameters, but it can be applied to choice RTs even in the case where there are few or no repeated measurements of each participant-item combination. Different aspects of the response process are then linked to different types of item properties. A typicality measure turns out to predict the rate of information uptake, while a lexicographic measure predicts the stimulus encoding time. Accessibility measures cannot reliably predict any component of the decision process.
doi:10.1016/j.actpsy.2009.10.009 pmid:19962683 fatcat:p3vzq7v6ebhgtaekyziui7xnky