5 Shared Information Bias

Original content remixed from FEMA’s guide on Group Decision Making, The Noba Project, and Wikipedia, the free encyclopedia.

Group decision-making is complex. There are certain conditions that make group decision-making more desirable:

  1. The situation is complex.

  2. Consequences are significant.

  3. Commitment and buy-in are important.

  4. There is time for deliberation and consensus building.

When there is sufficient motivation for group decision-making, it is critical to be aware of some of the biases or complexities that group conversation can invite. This chapter briefly reviews Shared Information Bias and the Hidden Profile Task. As you read, try to consider why this bias is important to keep in mind.

Sushma Berlia, President, Apeejay Stya & Svran Group, talking about the need for eduction in India
Picture of people deliberating. Credit: Horasis https://bit.ly/3rH1FNl

One of the advantages of making decisions in groups is the group’s greater access to information. When seeking a solution to a problem, group members can put their ideas on the table and share their knowledge and judgments with each other through discussions. But all too often groups spend much of their discussion time examining shared information—information that two or more group members know in common—rather than unshared information. This shared information bias will result in a bad outcome if something known by only one or two group members is very important.

Researchers have studied this bias using the hidden profile task. On such tasks, information known to many of the group members suggests that one alternative, say Option A, is best. However, Option B is definitely the better choice, but all the facts that support Option B are only known to individual groups members—they are not common knowledge in the group. As a result, the group will likely spend most of its time reviewing the factors that favor Option A, and never discover any of its drawbacks. In consequence, groups often perform poorly when working on problems with nonobvious solutions that can only be identified by extensive information sharing (Stasser & Titus, 1987).

Sharing information with other group members is associated with group member perceptions of competence, knowledge, and credibility (Wittenbaum & Park, 2001). According to Broderick et al., (2007), information known to only a single member of a group prior to group discussion will be mentioned less often and evaluated less favorably compared with information known to multiple group members prior to a group discussion.This phenomenon describes shared information bias (Baker, 2010). Shared information bias (or the hidden profile problem) is thus a tendency for group members to spend more time and energy discussing information that multiple members are already familiar with (i.e., shared information). Researchers predict poor decision-making can arise when the group does not have access to unshared information for making well-informed decisions. The result of inaccessible unshared information is called hidden profiles. Hidden profiles describe group decision tasks in which different (but correct) possible solutions exist, but no group member detects it based on his or her individual information prior to the discussion (Stasser, 1988).


Although discussing unshared information may be enlightening, groups are often motivated to discuss shared information in order to reach group consensus on some course of action. According to Postmes et al., (2001), when group members are motivated by a desire to reach closure (e.g., a desire imposed by time constraints), their bias for discussing shared information is stronger. However, if members are concerned with making the best decision possible, this bias becomes less salient.

Stewart and Stasser (1998) have asserted that the shared information bias is strongest for group members working on ambiguous, judgment-oriented tasks because their goal is to reach consensual agreement than to distinguish a correct solution. The shared information bias may also develop during group discussion in response to the interpersonal and psychological needs of individual group members. For example, some group members tend to seek group support for their own personal opinions. This psychological motivation to garner collective acceptance of one’s own initial views has been linked to group preferences for shared information during decision-making activities (Greitemeyer & Schulz-Hardt, 2003; Henningsen & Henningsen, 2003).

Lastly, the nature of the discussion between group members reflects whether biases for shared information will surface. According to Wittenbaum et al. (2004), members are motivated to establish and maintain reputations, to secure tighter bonds, and to compete for success against other group members. As a result, individuals tend to be selective when disclosing information to other group members.


Sign that says: If you see something, say nothing
Shared information bias is about sharing what you know, even if you think it might be irrelevant, tangential, or unrelated. Credit: pedrik https://bit.ly/2UV28zt

Focusing on shared information leads teams to make poorer decisions and often to ignore critical information that might help facilitate better decision outcomes. Wittenbaum et al. (1999) examined mutual enhancement during various discussions about job candidates (i.e., interactions between two people). Participant dyads were assigned to one of two conditions. Before meeting to discuss candidate profiles, researchers had dyads in the first condition look at same information about candidates, while the second condition had dyads receive different information. Participants in condition one evaluated both their partner and self as more component and credible.

Teams which engage in shared information bias are often unable to come to the best conclusion because they do not share all relevant information. The shared information bias demonstrates the importances of thoughtful and sustained deliberation. Shared information bias also highlights how we often are unsure what we need to share to help solve the problem. Thus, sharing openly any potentially helpful information is essential if teams expect to succeed. If you think it might be useful–share it with the group!

Avoidance strategies

Several strategies can be employed to reduce group focus on discussing shared information:

  • Make effort to spend more time actively discussing collective decisions. Given that group members tend to discuss shared information first, longer meetings increase likelihood of reviewing unshared information as well.
  • Make effort to avoid generalized discussions by increasing the diversity of opinions within the group (Smith, 2008).
  • Introduce the discussion of a new topic to avoid returning to previously discussed items among members (Reimer, Reimer, & Hinsz, 2010).
  • Avoid time pressure or time constraints that motivate group members to discuss less information (Kelly & Karau, 1999; Bowman & Wittenbaum, 2012).
  • Clarify to group members when certain individuals have relevant expertise (Stewart & Stasser, 1995).
  • Include more group members who have task-relevant experience (Wittenbaum, 1998).
  • Technology (e.g., group decision support systems, GDSS) can also offer group members a way to catalog information that must be discussed. These technological tools (e.g., search engines, databases, computer programs that estimate risk) help facilitate communication between members while structuralizing the group’s decision-making process (Hollingshead, 2001).




  • Baker, D. F. (2010). Enhancing group decision making: An exercise to reduce shared information bias. Journal of Management Education, 34, 249-279.
  • Brodbeck, F.C., Kerschreiter, R., Mojzisch, A., & Schulz-Hardt, S. (2007). Group decision making under conditions of distributed knowledge: The information asymmetries model. Academy of Management Review, 32, 459-479.
  • Hollingshead, A. B. (2001). Cognitive interdependence and convergent expectations in transactive memory. Journal of Personality and Social Psychology, 8, 1080-1089. doi: 10.1037/0022-3514.81.6.1080
  • Stasser, G. (1988). Computer simulation as a research tool: The DISCUSS model of group decision making. Journal of Experimental Social Psychology, 24, 393–422.
  • Stasser, G., & Titus, W. (1985). Pooling of unshared information in group decision making: Biased information sampling during discussion. Journal of Personality and Social Psychology, 48, 1467–1478
  • Wittenbaum, G. M., Hubbell, A. P., & Zuckerman, C. (1999). Mutual enhancement: Toward an understanding of the collective preference for shared information. Journal of Personality and Social Psychology, 77, 967-978. doi: 10.1037/0022-3514.77.5.967
  • Wittenbaum, G. M., & Park, E. S. (2001). The Collective Preference for Shared Information. Current Directions in Psychological Science, 10, 70–73. https://doi.org/10.1111/1467-8721.00118




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Shared Information Bias Copyright © 2021 by Cameron W. Piercy, Ph.D. is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, except where otherwise noted.

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