Groupthink is a psychological concept that explains how people who make decisions in a group will actually pick a worse choice. This happens because individual members of the group don’t want to stand out too much, and choose the option they think everyone else will agree with in order to conform. There are examples of it throughout history, including in governments, such as the ideation of the Bay of Pigs, and the Watergate cover-up.
On the other hand, there are examples of it in groups working directly in opposition to the government. Terrorist organizations often don’t start violent, but can become more violent as time goes on. This is partially due to groupthink: members of these organizations will voice more and more extreme opinions if they think the rest of the group will agree. These organizations that form these radical and extreme opinions are often smaller subsets of larger organizations, as members of smaller groups of people with similar opinions are less likely to raise doubts about ideas or plans.
Many people have tried to figure out how to solve, or lessen the effects of, groupthink, but this dangerous concept will continue to affect decision-making for a long time to come.