The incubation effect describes the phenomenon of performance improvement after being away from a hard task for some time. Though much research has been done, the mechanism(s) underlying this effect was unclear yet, together with a lack of studies in groups. The current study examined the incubation effect in a group context using dyads and explored the effects of cognitive demand of interpolated task and emotions on the incubation effect, in hope of deepening understanding of possible mechanisms of the incubation effect. Four experiments were conducted: Experiments 1-3 manipulated cognitive demand of interpolated task and Experiment 4 manipulated emotions during incubation. Three divergent thinking tasks were employed: Experiments 1 and 4 employed alternative uses task, Experiment 2 employed instances task and Experiment 3 employed consequences task. Participants in each trial worked together with their partner on a creativity task, then worked on the designated interpolated task, then came back and worked on the same creativity task again, except in no-incubation condition where they worked on the creativity task continuously.The results showed trends that fit the incubation effect in Experiments 2 and 3, but no significant effect of cognitive demand of interpolated task or emotions during incubation was found on the proposed group incubation effect. Possible reasons might come from the setup of cognitive demand levels and emotion conditions, or the relatively weak nature of the incubation effect. Future studies on the group incubation effect should carefully set conditions and explore more group sizes for the generalizability concern.