Shared Information Bias
Collective Information Sampling Bias
The tendency for group members to spend more time and energy discussing information that all members are already familiar with (i.e., shared information), and less time and energy discussing information that only some members are aware of (i.e., unshared information).
Origin
Psychologists Garold Stasser and William Titus identified shared information bias through their foundational 1985 research using the "hidden profile" task experimental design. Their study demonstrated that teams often fail to reach their decision-making potential because they overweight information all members already know and underweight information only some members possess. The research showed that even when a group collectively holds all necessary information to make optimal decisions, individual members lacking complete information prevent the group from assembling the full picture.