Multi-factor analysis in language production: Sequential sampling models mimic and extend regression results
Résumé
For multi-factor analyses of response times, descriptive models (e.g. linear regression) arguably constitute the dominant approach in psycholinguistics. In contrast empirical cognitive models (e.g. sequential sampling models, SSMs) may fit fewer factors simultaneously, but decompose the data into several dependent variables (a multivariate result), offering more information to analyze. While SSMs are notably popular in the behavioral sciences, they are not significantly developed in language production research. To contribute to the development of this modeling in language, we (i) examine SSMs as a measurement modeling approach for spoken word activation dynamics, and (ii) formally compare SSMs to the default method, regression. SSMs model response activation or selection mechanisms in time, and calculate how they are affected by conditions, persons, and items. While regression procedures also model condition effects, it is only in respect to the mean RT, and little work has been previously done to compare these approaches. Through analyses of two language production experiments, we show that SSMs reproduce regression predictors, and further extend these effects through a multivariate decomposition (cognitive parameters). We also examine a combined regression-SSM approach that is hierarchical Bayesian, which can jointly model more conditions than classic SSMs, and importantly, achieve by-item modeling with other conditions. In this analysis, we found that spoken words principally differed from one another by their activation rates and production times, but not their thresholds to be activated.