Belief bias refers to the phenomenon in which people's judgments about the logical strength of an argument are influenced by their prior beliefs about the conclusion of the argument. This means that people are more likely to accept an argument as logically sound if it supports their preexisting views, and more likely to reject an argument as unsound if it contradicts their preexisting views.

Belief bias can have significant consequences when it comes to group decision making, as it can lead to a lack of critical thinking and a failure to consider alternative perspectives. When individuals in a group are affected by belief bias, they may be less likely to question their own assumptions or to consider other viewpoints, which can lead to groupthink and a lack of diversity in decision making.

One of the key ways that belief bias can be mitigated in group decision making is through the use of structured decision-making processes that encourage critical thinking and the consideration of alternative perspectives. For example, incorporating a devil's advocate or a red team approach can help to challenge assumptions and encourage the consideration of alternative viewpoints. Additionally, creating a culture of open-mindedness and curiosity can help to create an environment in which individuals feel comfortable questioning their own assumptions and considering other perspectives.

Another way to mitigate belief bias in group decision making is through the use of data and facts to support arguments. When individuals are presented with evidence that contradicts their preconceptions, they may be more likely to question their own beliefs and to consider alternative perspectives. Additionally, the use of data and facts can help to neutralize the influence of personal biases in decision making, as the evidence itself can speak for itself.