The Research Group of Quantitative Psychology and Individual Differences prides itself for being a hybrid group in terms of its research focus. Our researchers combine the empirical and theoretical study of substantive psychological issues (with key themes emotion and affect dynamics) with the formal study of statistical and methodological issues. Typically, the two types of study meet in a fruitful middle ground, where substantive questions inspire the development of new methods, models and algorithms, and where novel models and methods shed new light on substantive questions (and lead to a deepening of those). This hybrid nature is reflected in the background and expertise of the group members, who may find themselves at different places in the substantive-methodological spectrum at different times.