XXCognitive Bias
Shared Information Bias
Your bias is Shared Information. Groups overfocus on commonly known information.
Why This Bias Happens
Groups seek social ease. Discussing what everyone already knows builds cohesion faster than testing unique, uncertain evidence.
Example 1
Marcus praises speaking only what is necessary and true. In groups, that discipline includes raising the uncommon but relevant fact.
Example 2
Research on hidden-profile tasks shows groups discuss shared facts more and overlook unshared information that would improve decisions.