In groupthink theory, a mindguard is a member of a group who serves as an informational filter, providing limited information to the group and, consciously or subconsciously, utilizing a variety of strategies to control dissent and to direct the decision-making process toward a specific, limited range of possibilities.^[1] The presence of mindguards within a group is one of eight main "symptoms" of groupthink identified by its original theorist, Irving Janis.^[2] Mindguards can be self-appointed,^[2] and multiple mindguards are frequently present in groupthink situations.

The techniques utilized, consciously or subconsciously, by mindguards include:

• time pressure in regard to decision-making
• bandwagon effect/information cascades
• reframing situations to increase pressure toward or away from a specific outcome
• creating a sense that group cohesion will suffer if unanimity is lacking
• other techniques.^[3]

Mindguards exist in a variety of group settings.^{[citation needed]} They are not always easy to identify, which adds to the difficulty in countering the phenomenon.

• Gatekeeping (communication)