By Catherine A. Sanderson, Amherst College
We all have the tendency to be overconfident in our judgments about virtually everything. In one high-profile example of overconfidence, on October 18, 2016, Sam Wang, a Princeton University professor and polling expert, tweeted, “It is totally over. If Trump wins more than 240 electoral votes, I will eat a bug.” The consequence of that tweet was “Sam Wang eats a bug”, a video that played on CNN.

Overconfidence and Groupthink
Daniel Kahneman, a Nobel Prize winner, explains overconfidence as a bias that includes over-emphasis on ‘known knowns’, a down rating of ‘known unknowns’ and outright dismissal of any so-called ‘unknown unknowns’. College students are overconfident about how quickly they can finish that paper, which then forces them to pull an all-nighter when it takes longer than what they overconfidently expected.
The error of overconfidence is one that can lead to serious, even deadly, consequences. This is especially true when we are making decisions, or attempting to solve problems, as part of a group. The term ‘groupthink’ describes a group decision-making style that occurs when group members prioritize reaching unanimous agreement, instead of making the best decision.
This tendency of being overconfident is especially likely to occur when group members are all very similar to one another, are isolated from divergent viewpoints, and have a strong leader who discourages deviant opinions. This tendency toward groupthink is also more likely when the decision is highly stressful and must be made quickly.
Reasons for Being Overconfident
Groupthink includes a tendency for groups to be overconfident in their approach to making decisions, for at least three distinct reasons: First, a tendency to overestimate invulnerability and morality; a belief that whatever the group decides, it’s the right choice, and there are no potential flaws or downsides to the decision.
The second reason is being closeminded to the opinions of those outside the group; a belief that non-group members don’t really have important insights to add. The third reason is a pressure toward unanimity among group members; people who dissent from the decision favored by a majority of the group are likely to be expelled, or shunned, which leads group members to feel reluctant to express any dissenting views.
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Bad Decision-making
A vivid example of bad decision-making resulting from groupthink was revealed in 2012, when the Penn State University community was stunned by a scathing report led and released by former FBI Director, Louis Freeh, describing the cover-up of the child-sexual abuse scandal by numerous high-level administrators.
As this report clearly demonstrated, members of the Penn State administration became aware of very serious and criminal accusations of inappropriate sexual behavior committed by then assistant coach Jerry Sandusky.
But what the university did was create a very insular group to discuss how to respond. They failed to consult with people outside the administrator group. As the administrator emails later revealed, they worried far more about the potential damage to themselves and the institution, showing a bias called loss aversion. They, therefore, decided not to report the allegations to the police, despite the risk of that choice for future victims. In fact, they even convinced themselves that their choice to cover up these allegations was better for the children who had been victimized.
Relying on Groupthink
And yet, groupthink happens in groups of all kinds, including scientific organizations.
In 1986, the leaders at NASA decided to go ahead with the launch of the space shuttle Challenger despite concerns raised about the potential for a catastrophic failure. This decision led to the death of all seven people on board, just 73 seconds after lift-off.

As President John F. Kennedy later reflected after his reliance on groupthink led to the failed Bay of Pigs invasion during the first months of his administration: “Without debate, without criticism, no administration and no country can succeed and no republic can survive.”
Groupthink is also seen in religious communities, who in theory should prioritize morally good behavior above all else. But as outlined in the 2018 grand jury report of sexual abuse within the Catholic clergy in Pennsylvania, “Church leaders … preferred to protect the abusers and their institution above all… Priests were raping little boys and girls, and the men of God who were responsible for them not only did nothing; they hid it all. For decades.”
Human Tendency to Make Errors

After these difficult examples, it’s important to remember that such errors are not inevitable. In fact, simply knowing about the very natural human tendency to make these errors can help us overcome them. Once we are aware of our tendency to take shortcuts—such as focusing on whatever comes to mind more quickly—there are specific steps one can take to overcome these errors, reduce the chance of jumping too quickly to a wrong conclusion, and make better decisions.
Perhaps the leading factor that leads to errors is a desire to reach a fast decision. That’s why people worry more about the risk of school shooters or plane crashes than they should, but underestimate the bigger risk involved in texting while driving.
Thus, it’s worth making sure the group actively seeks out and listens to the views and opinions of people outside the group. And, it’s also important to encourage people within the group with dissenting views to speak up. Perhaps most importantly, choose a leader who fosters active debate and encourages criticism.
Common Questions about Groupthink and the Error of Overconfidence
Groupthink describes a group decision-making style that occurs when group members prioritize reaching unanimous agreement, instead of making the best decision.
This tendency of being overconfident is especially likely to occur when group members are all very similar to one another, are isolated from divergent viewpoints, and have a strong leader who discourages deviant opinions.
A major factor that leads to errors is a desire to reach a fast decision.