In committees, commissions or teams - in any kind of group that has a common task - various group biases can influence group results like decisions. Whether it is that people of higher in status or authority do not only speak more (status expectation effect), their opinions are also attributed more importance and accuracy - independently of the content (authority bias). Similarly, conformity (adapting to the predominant group opinion) or withholding information due to the "shared information bias" can have a highly damaging effect on group decision making, research processes and thus scientific success. How such phenomena can be recognized, what this has to do with diversity and innovation, and how these group effects can be reduced, is the focus of this lecture.