"Six thinking hats" is a decision making tool developed by psychologist and physician Edward de Bono. In wearing a particular hat, people play roles or "as if" themselves into a particular perspective
Wear a white hat and present the facts of the case,generate ideas using green hat,evaluate the merits with yellow hats,demerits with a black hat,think of alternatives using red hat ,and adjourn the meeting with a blue hat.
Science has a nice piece of advice on Mastering your Phd/research by adopting this tool in regular lab group meetings.
Blue hat is tricky.
It is not always "What a fantastic idea! Let’s go for it!" hat.