Which technique assumes that if most people believe something, it must be true?

The technique that assumes that if most people believe something, it must be true is the concept of majority belief. This principle suggests that the widespread acceptance of an idea or viewpoint by a large group lends it a perceived legitimacy or truthfulness. It is based on the social proof heuristic, where individuals look to the actions or beliefs of others to guide their own decisions, particularly in uncertain situations.

In contrast, minority influence refers to the effect that a smaller group can have on a larger group, often leading to change in attitudes or behaviors through consistency and confidence. Groupthink involves the tendency of group members to conform to one another's viewpoints, often leading to poor decision-making as they prioritize harmony over critical analysis. Authoritarian influence relates to power dynamics and coercion, suggesting influence derived from authority rather than consensus or belief.

Thus, majority belief effectively encapsulates the assumption that the popularity of a belief correlates with its truth.