A response model that is able to detect guessing behaviors and produce unbiased estimates in low-stake conditions using timing information is proposed. The model is a special case of the grade of membership model in which responses are modeled as partial members of a class that is affected by motivation and a class that responds only according to…

The authors propose and test a simple model of the time course of visual identification of briefly presented, mutually confusable single stimuli in pure accuracy tasks. The model implies that during stimulus analysis, tentative categorizations that stimulus i belongs to category j are made at a constant Poisson rate, v(i, j). The analysis is…

Data from two samples of 32,862 and 6,757 males, respectively, from the Danish draft board indicate that gains in intelligence test scores are continuing and are concentrated among lower intelligence levels. Monte Carlo simulations suggested that this distributional change did not result from a ceiling effect in the test. (SLD)