Groupthink is the psychological phenomenon that occurs when an individual's desire for consensus and acceptance from a group of people overrides the individual's desire to present alternatives, critique a position, or express an unpopular opinion to that group. It sometimes leads to that individual adopting the opinion of the majority. From an evolutionary standpoint, groupthink stemmed from the need for early humans to form harmonious groups to survive.
In modern times, groupthink remains a powerful factor in human psychology. It subconsciously influences the way we interact with others in many social, political and business contexts.