In a fast-changing world, constantly innovating remains one of the principal challenges most organizations are facing nowadays. Survival of organizations became principally linked to the creative generation capacity of their staffs. Nonetheless, fixation imposes a key constraint to the aptitude of individuals to constantly come up with innovative ideas. Numerous studies have highlighted the significant role that could be played by leadership in this regard. Nevertheless, most of these works studied leadership's role from a social perspective, reducing the function of creative leaders as facilitators. From a more cognitive perspective, very few works have shed the light on the role of creative leaders during ideation processes. However, very recent studies showed that leaders could efficiently play the role of de-fixators, by preparing carefully their interventions (instructions, feedbacks, etc.) within the ideation process, according to their capacity to recognize the frontier between fixation and de-fixation of a project. In the present paper, we have furthered these findings, by exploring the effect of feedbacks, in specific cases in which leaders lead their teams in the unknown with imperfect knowledge. Based on varying levels of knowledge (leaders' ability to recognize if a particular idea generated by his team is inside or outside fixation), we implemented a theoretical model for ideation management using design and probability theories. Using a theory-driven experimental procedure, we showed in this paper that leadership strategies for ideation management should adopt less generic and universal tactics (such as brainstorming rules for example), but rather more situational approaches depending on followers' capacity to think out of the dominant design. 2