The theory that groups will spend longer debating trivial things than complicated issues.

This can occur because people may realize that they do not understand a complex issue well, and trust that those who are more knwoledgeable than themselves will sort it out. When it comes time to discuss a simpler issue however, everyone believes that they can contribute to the matter well and so many conflicting opinions are given, requiring lots of further debate. The name comes from a theoretical group discussing a nuclear reactor and a bike shed.