What is it called when everyone believes and thinks the same way in a society?

When everyone in a society believes and thinks the same way, it is often referred to as "groupthink." This phenomenon occurs when the desire for harmony and conformity in a group leads to irrational or dysfunctional decision-making, as individuals suppress dissenting viewpoints. It can hinder creativity and critical thinking, resulting in a lack of diversity in opinions and ideas. Additionally, it may create an environment where alternative perspectives are not valued or considered.