A dynamic model of group performance is suggested that combines the group learning approach and the combination of contributions approach. Three hypotheses are tested in two experiments, comparing individual training conditions with mixed group and individual training conditions on subsequent nominal and collective group performance of rule induction tasks under identical time constraints. As predicted, collective group performance improves as a function of group experience, nominal group performance improves as a function of improved individual resources for performing the task individually, and group experience reduces process losses by improving individuals' ability to collaborate efficiently. Several experiments from the literature that address issues of group learning are analyzed in the light of the propositions made in the dynamic model. Overall, theoretical and experimental approaches to investigating group learning phenomena are discussed.We present a dynamic model of group performance that integrates theoretical work and experimental research on group learning phenomena. The model is guided by the assumption that actual group performance is a function of group potential performance minus process loss plus process gain (e.g. Forsyth, 1999). Furthermore, it combines two theoretical approaches to the study of small group performance, the combination of contributions approach and the group learning approach. The essential assumption of the combination of contributions approach is that group interaction can be modeled as a mapping process from a dispersed array of group members' resources (e.g. correct or incorrect responses to a logic problem) to a single group response (for a G P I R