Another project involves trying to predict individual differences in performing cognitive tasks by attempting to model individual subject performance in one task, using an estimate of that subject's working memory capacity, derived from a different experiment. That is, a single, individual difference parameter is estimated in one task and is used to fit an individual's performance across several tasks that vary in cognitive load. Almost all previous cognitive modeling efforts have been on aggregate data (averaged across subjects). Past efforts to model individual differences have aggregated subjects into two, or at most three, groups, e.g., low vs. high spatial, or low vs. high verbal.