On January 28, 1986 the space shuttle Challenger broke apart less than two minutes into its 10th mission taking the lives of all seven people aboard.
The commission created by President Reagan to investigate the cause of the disaster found that the failure of an O ring led to structural failure of the vehicle and also strongly criticised the decision making process that led to the launch going ahead despite concerns being raised by the contractor responsible for O rings, Morton Thiokol.
The psychological phenomenon commonly called "Groupthink" was identified as a major factor. Irving Janis, a psychologist at Yale University is credited with introducing the concept when his book Victims of Groupthink was published in 1972.
According to Janis Groupthink happens when a group makes faulty decisions due to the desire to maintain conformity and harmony. Alternative views are suppressed and anyone criticising the decisions are marginalised and dehumanised.
Janis identified a number of ways for decision makers to avoid Groupthink. They include, among others; allow members to be "critical evaluators" so they can express contrary views without sanction; leaders should allow members plenty of opportunity to discuss matters without their presence so they don't dominate; effective alternatives should be evaluated; at least one member should be appointed "devil's advocate" and the role should move between members.