Groupthink: how your leadership team makes bad decisions without knowing it

On 28 January 1986, the space shuttle Challenger exploded 73 seconds after launch. Seven astronauts lost their lives. The inquiry revealed that engineers at Morton Thiokol had warned the night before about the risk of seal failure in cold weather. Their warnings had been dismissed. The decision to launch had been taken over their objections.

The Bay of Pigs, in 1961: the Kennedy administration approved a Cuba invasion plan developed under Eisenhower, ignoring obvious signals of its strategic impossibility. The failure was total and humiliating.

Pearl Harbor, Watergate, the 2008 subprime crisis. These disasters were analysed in depth by psychologist Irving Janis, who identified a common mechanism he named groupthink in 1972: the tendency of a cohesive, tight-knit group to converge toward consensus without exercising any critical thinking.

The three symptoms of groupthink

Groupthink manifests through recognisable signals, found in the deliberations of leadership teams under strong decisional pressure.

First symptom: the illusion of invulnerability. The group develops excessive optimism and an abnormally high risk tolerance. In the Challenger launch dynamic, this translates as: '1% risk of overheating, nothing to worry about.' The danger is minimised because the group has succeeded too often to seriously contemplate failure.

Second symptom: excessive rationalisation. The group collectively constructs justifications for ignoring information that contradicts the consensus. The decision is not questioned; arguments are sought to validate it. Critical vigilance is extinguished in favour of cohesion.

Third symptom: the illusion of unanimity. Silent members are perceived as approving. Since no one shouts 'Stop!', everyone assumes everyone else agrees. It is silence that founds the consensus, not conviction.

« In a group subject to groupthink, the question is no longer 'what is the best decision?' but 'how do we avoid challenging the consensus?' »

— Irving Janis, Victims of Groupthink (1972)

Solomon Asch and conformity: an irresistible pressure?

In 1951, psychologist Solomon Asch conducted a now-famous series of experiments. He showed participants a reference line and asked them to identify which of three other lines was the same length. The correct answer was obvious. But in the group, several confederates deliberately gave the wrong answer.

Result: 75% of subjects conformed at least once to the group's incorrect answer. Many denied the reality of their own perceptions in order not to stand out from the majority.

What Asch demonstrated is fundamental for any decision-maker: conformity pressure in a group is not experienced as a conscious constraint. It is internalised. It operates below the threshold of reason. Intelligent, informed people with good judgement can collectively align with a manifest error, simply to preserve group harmony.

The solution: institutionalising the devil's advocate

The managerial solution to groupthink is not to undermine team cohesion or create a climate of suspicion. It is more elegant and more robust: institutionalise the role of dissenter.

The devil's advocate practice consists of officially designating, for each significant deliberation, a member whose explicit role is to challenge the emerging consensus. This role rotates, it does not stigmatise one individual as 'the one who always says no', and it is formally legitimate, which removes the social pressure against questioning.

Research in organisational psychology shows that this simple practice is sufficient to significantly reduce confirmation bias and social harmony bias in collective decision-making.

Other complementary practices include the pre-mortem technique (imagining that the decision has already failed before taking it, and identifying the reasons) and the systematic consultation of expertise external to the decision-making body for major strategic decisions.

The leader who does not seek consensus at all costs, but who protects the quality of the deliberative process, is the one who shields their organisation from its most costly collective errors.