Groupthink

Also Known As: Gruppendenken Group Think Janis Groupthink

Cognitive Bias ID: groupthink

Definition

Groupthink is a psychological phenomenon where the desire for conformity and harmony within a group overrides realistic appraisal of alternatives. Identified by Irving Janis in 1972, it occurs when group members suppress dissent, fail to critically evaluate ideas, and develop an illusion of invulnerability, leading to poor decisions.

Examples

A corporate board unanimously approves a risky acquisition because no one wants to be the dissenter. The CEO is enthusiastic, and board members who have doubts stay silent to preserve group harmony.

A project team keeps moving forward with a failing strategy because everyone assumes the others must know something they don't, and no one wants to be the first to raise the alarm.

A jury reaches a quick unanimous verdict because the first few outspoken members set the direction, and the rest conform rather than prolong deliberations with their doubts.

Formal Logic Pattern

FOL Pattern

The First-Order Logic formula representing this reasoning pattern's logical structure.

FOL (First-Order Logic) uses quantifiers (∀ = for all, ∃ = there exists), connectives (∧ = and, ∨ = or, ⇒ = implies, ¬ = not), and predicates to capture the essential form of a reasoning pattern. For example, the Ad Hominem fallacy: Person(x) ∧ HasFlaw(x) ⇒ Invalid(Claim(x)). These patterns allow automated verification of logical validity.

View in glossary →

∃G∃d(Group(G) ∧ Decision(d) ∧ DesireHarmony(G) → Suppresses(G, Dissent) ∧ ¬CriticalEval(G,d))

Verification Steps

Verification Steps

Binary yes/no questions that an AI must answer to detect a reasoning pattern in a text.

Each of the 452 aspects has verification steps — simple yes/no questions designed to systematically detect whether a pattern appears in a text. For ad hominem: "Does the argument attack a person rather than their claim?" For false dichotomy: "Are only two options presented when more exist?" This ensures consistent, reproducible analysis.

View in glossary →

Binary (yes/no) questions an LLM must answer to identify this aspect:

1

Was the decision made by a cohesive group that values consensus?
Type: binary
2

Were dissenting opinions discouraged, ignored, or self-censored?
Type: binary
3

Did the group fail to consider alternative courses of action or seek outside opinions?
Type: binary
4

Is there an illusion of unanimity where silence is interpreted as agreement?
Type: binary

Description

Why It Works

Humans have a deep need for social belonging. In cohesive groups, the fear of being ostracized or seen as disloyal is stronger than the desire to voice concerns. Strong leadership, isolation from outside opinions, and time pressure amplify the effect.

How to Counter

Appoint a devil's advocate for each major decision. Encourage anonymous feedback. Bring in outside experts. Have the leader speak last. Break into subgroups to develop independent assessments before reconvening.

Also Known As

Gruppendenken Group Think Janis Groupthink

Real-World Context

The Bay of Pigs invasion (1961) is the textbook example: Kennedy's advisors suppressed doubts about the CIA plan. The Challenger disaster (1986) is another case where engineers' concerns were overridden by group pressure to launch.

Related Aspects

False Consensus Effect Authority Bias

Hierarchical Context

→ is a Social Biases

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