Group Decision Making

In the previous section, we explored some of the important ways that being in a group affects individual group members’ behavior, and, in turn, influences the group’s overall performance. As well as achieving high levels of performance, another important task of groups is to make decisions. Indeed, we often entrust groups, rather than individuals, with key decisions in our societies—for example, those made by juries and political parties. An important question to ask here is whether we are right to trust groups more than individuals to reach sound decisions. Are many heads really better than one?

It turns out that this question can be a hard one to answer. For one thing, studying decision making is hard, because it is difficult to assess the quality of a decision on the basis of what was known at the time, independently of its outcome. This is particularly challenging as we naturally tend to look too much at the outcome when we evaluate decision making. Moreover, studying decision making in laboratory environments has generally involved providing group members with more information than they would typically have in the real world (Johnson & Johnson, 2012), and so the results may not always generalize here.

Nevertheless, with these caveats in mind, it is possible to draw some tentative conclusions about when and why groups make better decisions than individuals, and also when and why they may end up making worse ones.

Process Gains in Group versus Individual Decision Making

Process Losses Due to Group Conformity Pressures: Groupthink

Groups can make effective decisions only when they are able to make use of the advantages outlined above that come with group membership. However, these conditions are not always met in real groups. As we saw in the chapter opener, one example of a group process that can lead to very poor group decisions is groupthink. Groupthink occurs when a group that is made up of members who may actually be very competent and thus quite capable of making excellent decisions nevertheless ends up making a poor one as a result of a flawed group process and strong conformity pressures (Baron, 2005; Janis, 2007).

Groupthink is more likely to occur in groups in which the members are feeling strong social identity—for instance, when there is a powerful and directive leader who creates a positive group feeling, and in times of stress and crisis when the group needs to rise to the occasion and make an important decision. The problem is that groups suffering from groupthink become unwilling to seek out or discuss discrepant or unsettling information about the topic at hand, and the group members do not express contradictory opinions. Because the group members are afraid to express ideas that contradict those of the leader or to bring in outsiders who have other information, the group is prevented from making a fully informed decision. Figure 10.7, “Antecedents and Outcomes of Groupthink,” summarizes the basic causes and outcomes of groupthink.

Although at least some scholars are skeptical of the importance of groupthink in real group decisions (Kramer, 1998), many others have suggested that groupthink was involved in a number of well-known and important, but very poor, decisions made by government and business groups. Key historical decisions analyzed in terms of groupthink include the decision to invade Iraq made by President George Bush and his advisors, with the support of other national governments, including those from the United Kingdom, Spain, Italy, South Korea, Japan, Singapore, and Australia; the decision of President John F. Kennedy and his advisors to commit U.S. forces to help with an invasion of Cuba, with the goal of overthrowing Fidel Castro in 1962; and the policy of appeasement of Nazi Germany pursued by many European leaders in 1930s, in the lead-up to World War II. Groupthink has also been applied to some less well-known, but also important, domains of decision making, including pack journalism (Matusitz, & Breen, 2012). Intriguingly, groupthink has even been used to try to account for perceived anti-right-wing political biases of social psychologists (Redding, 2012).  

Careful analyses of the decision-making process in the historical cases outlined above have documented the role of conformity pressures. In fact, the group process often seems to be arranged to maximize the amount of conformity rather than to foster free and open discussion. In the meetings of the Bay of Pigs advisory committee, for instance, President Kennedy sometimes demanded that the group members give a voice vote regarding their individual opinions before the group actually discussed the pros and cons of a new idea. The result of these conformity pressures is a general unwillingness to express ideas that do not match the group norm.

The pressures for conformity also lead to the situation in which only a few of the group members are actually involved in conversation, whereas the others do not express any opinions. Because little or no dissent is expressed in the group, the group members come to believe that they are in complete agreement. In some cases, the leader may even select individuals (known as mindguards) whose job it is to help quash dissent and to increase conformity to the leader’s opinions.

An outcome of the high levels of conformity found in these groups is that the group begins to see itself as extremely valuable and important, highly capable of making high-quality decisions, and invulnerable. In short, the group members develop extremely high levels of conformity and social identity. Although this social identity may have some positive outcomes in terms of a commitment to work toward group goals (and it certainly makes the group members feel good about themselves), it also tends to result in illusions of invulnerability, leading the group members to feel that they are superior and that they do not need to seek outside information. Such a situation is often conducive to poor decision making, which can result in tragic consequences.

Interestingly, the composition of the group itself can affect the likelihood of groupthink occurring. More diverse groups, for instance, can help to ensure that a wider range of views are available to the group in making their decision, which can reduce the risk of groupthink. Thinking back to our case study, the more homogeneous the group are in terms of internal characteristics such as beliefs, and external characteristics such as gender, the more at risk of groupthink they may become (Kroon, Van Kreveld, & Rabbie, 1992). Perhaps, then, mixed gender corporate boards are more successful partly because they are better able to avoid the dangerous phenomenon of groupthink.

Cognitive Process Losses: Lack of Information Sharing

Although group discussion generally improves the quality of a group’s decisions, this will only be true if the group discusses the information that is most useful to the decision that needs to be made. One difficulty is that groups tend to discuss some types of information more than others. In addition to the pressures to focus on information that comes from leaders and that is consistent with group norms, discussion is influenced by the way the relevant information is originally shared among the group members. The problem is that group members tend to discuss information that they all have access to while ignoring equally important information that is available to only a few of the members, a tendency known as the shared information bias (Faulmüller, Kerschreiter, Mojzisch, & Schulz-Hardt, 2010; Reimer, Reimer, & Czienskowski (2010).

Although the tendency to share information poorly seems to occur quite frequently, at least in experimentally created groups, it does not occur equally under all conditions. For one, groups have been found to better share information when the group members believe that there is a correct answer that can be found if there is sufficient discussion (Stasser & Stewart, 1992), and if they are forced to continue their discussion even after they believe that they have discussed all the relevant information (Larson, Foster-Fishman, & Keys, 1994). These findings suggest that an important job of the group leader is to continue group discussion until they are convinced that all the relevant information has been addressed.

The structure of the group will also influence information sharing (Stasser & Taylor, 1991). Groups in which the members are more physically separated and thus have difficulty communicating with each other may find that they need to reorganize themselves to improve communication. And the status of the group members can also be important. Group members with lower status may have less confidence and thus be unlikely to express their opinions. Wittenbaum (1998) found that group members with higher status were more likely to share new information. However, those with higher status may sometimes dominate the discussion, even if the information that they have is not more valid or important (Hinsz, 1990). Groups are also likely to share unique information when the group members do not initially know the alternatives that need to be determined or the preferences of the other group members (Mojzisch & Schulz-Hardt, 2010; Reimer, Reimer, & Hinsz, 2010).

Findings showing that groups neither share nor discuss originally unshared information have very disconcerting implications for group decision making because they suggest that group discussion is likely to lead to very poor judgments. Not only is unshared information not brought to the table, but because the shared information is discussed repeatedly, it is likely to be seen as more valid and to have a greater influence on decisions as a result of its high cognitive accessibility. It is not uncommon that individuals within a working group come to the discussion with different types of information, and this unshared information needs to be presented. For instance, in a meeting of a design team for a new building, the architects, the engineers, and the customer representatives will have different and potentially incompatible information. Thus leaders of working groups must be aware of this problem and work hard to foster open climates that encourages information sharing and discussion.

Given its obvious pitfalls, an interesting question to ask is why the shared information bias seems to be so pervasive. Recalling the confirmation bias that we discussed in the chapter on social cognition, perhaps it reflects this tendency played out at the group level, where group members collaborate to provide confirmatory evidence for each other’s positions. Leading on from this, it could also reflect the tendency for people to wish to use groups to reinforce their own views. Perhaps sometimes groups become places where people seek to mutually validate each other’s shared perspectives, to the detriment of them searching out the alternatives. If these ideas are correct, given that we often choose to associate with similar others, then it may be important to seek out the views of group members that are likely to be most different from our own, in seeking to weaken the damaging effects of the shared information bias (Morrow & Deidan, 1992).

Group Polarization

One common decision-making task of groups is to come to a consensus regarding a judgment, such as where to hold a party, whether a defendant is innocent or guilty, or how much money a corporation should invest in a new product. Whenever a majority of members in the group favors a given opinion, even if that majority is very slim, the group is likely to end up adopting that majority opinion. Of course, such a result would be expected, since, as a result of conformity pressures, the group’s final judgment should reflect the average of group members’ initial opinions.

Although groups generally do show pressures toward conformity, the tendency to side with the majority after group discussion turns out to be even stronger than this. It is commonly found that groups make even more extreme decisions, in the direction of the existing norm, than we would predict they would, given the initial opinions of the group members. Group polarization is said to occur when, after discussion, the attitudes held by the individual group members become more extreme than they were before the group began discussing the topic (Brauer, Judd, & Gliner, 2006; Myers, 1982). This may seem surprising, given the widespread belief that groups tend to push people toward consensus and the middle-ground in decision making. Actually, they may often lead to more extreme decisions being made than those that individuals would have taken on their own.

Group polarization was initially observed using problems in which the group members had to indicate how an individual should choose between a risky, but very positive, outcome and a certain, but less desirable, outcome (Stoner, 1968). Consider the following question:

Frederica has a secure job with a large bank. Her salary is adequate but unlikely to increase. However, Frederica has been offered a job with a relatively unknown startup company in which the likelihood of failure is high and in which the salary is dependent upon the success of the company. What is the minimum probability of the startup company’s success that you would find acceptable to make it worthwhile for Frederica to take the job? (choose one)

1 in 10, 3 in 10, 5 in 10, 7 in 10, 9 in 10

Research has found group polarization on these types of decisions, such that the group recommendation is more risky (in this case, requiring a lower probability of success of the new company) than the average of the individual group members’ initial opinions. In these cases, the polarization can be explained partly in terms of diffusion of responsibility (Kogan & Wallach, 1967). Because the group as a whole is taking responsibility for the decision, the individual may be willing to take a more extreme stand, since they can share the blame with other group members if the risky decision does not work out.

But group polarization is not limited to decisions that involve risk. For instance, in an experiment by Myers and Kaplan (1976), groups of students were asked to assess the guilt or innocence of defendants in traffic cases. The researchers also manipulated the strength of the evidence against the defendant, such that in some groups the evidence was strong and in other groups the evidence was weak. This resulted in two groups of juries—some in which the majority of the students initially favored conviction (on the basis of the strong evidence) and others in which a majority initially favored acquittal (on the basis of only weak evidence). The researchers asked the individuals to express their opinions about the guilt of the defendant both before and after the jury deliberated.

As you can see in Figure 10.8, “Group Polarization,” the opinions that the individuals held about the guilt or innocence of the defendants were found to be more extreme after discussion than they were, on average, before the discussion began. That is, members of juries in which the majority of the individuals initially favored conviction became more likely to believe the defendant was guilty after the discussion, and members of juries in which the majority of the individuals initially favored acquittal became more likely to believe the defendant was innocent after the discussion. Similarly, Myers and Bishop (1970) found that groups of college students who had initially racist attitudes became more racist after group discussion, whereas groups of college students who had initially antiracist attitudes became less racist after group discussion. Similar findings have been found for groups discussing a very wide variety of topics and across many different cultures.

The juries in this research were given either strong or weak evidence about the guilt of a defendant and then were either allowed or not allowed to discuss the evidence before making a final decision. Demonstrating group polarization, the juries that discussed the case made significantly more extreme decisions than did the juries that did not discuss the case. Data are from Myers and Kaplan (1976).

Group polarization does not occur in all groups and in all settings but tends to happen most often when two conditions are present: First, the group members must have an initial leaning toward a given opinion or decision. If the group members generally support liberal policies, their opinions are likely to become even more liberal after discussion. But if the group is made up equally of both liberals and conservatives, group polarization would not be expected. Second, group polarization is strengthened by discussion of the topic. For instance, in the research by Myers and Kaplan (1976) just reported, in some experimental conditions, the group members expressed their opinions but did not discuss the issue, and these groups showed less polarization than groups that discussed the issue.

Group polarization has also been observed in important real-world contexts, including financial decision making in corporate boardrooms (Cheng & Chiou, 2008; Zhu, 2010). It has also been argued that the recent polarization in political attitudes in many countries, for example in the United States between the “blue” Democratic states versus the “red” Republican states, is occurring in large part because each group spends time communicating with other like-minded group members, leading to more extreme opinions on each side. And some have argued that terrorist groups develop their extreme positions and engage in violent behaviors as a result of the group polarization that occurs in their everyday interactions (Drummond, 2002; McCauley, 1989). As the group members, all of whom initially have some radical beliefs, meet and discuss their concerns and desires, their opinions polarize, allowing them to become progressively more extreme. Because they are also away from any other influences that might moderate their opinions, they may eventually become mass killers.

Group polarization is the result of both cognitive and affective factors. The general idea of the persuasive arguments approach to explaining group polarization is cognitive in orientation. This approach assumes that there is a set of potential arguments that support any given opinion and another set of potential arguments that refute that opinion. Furthermore, an individual’s current opinion about the topic is predicted to be based on the arguments that they are currently aware of. During group discussion, each member presents arguments supporting their individual opinions. And because the group members are initially leaning in one direction, it is expected that there will be many arguments generated that support the initial leaning of the group members. As a result, each member is exposed to new arguments supporting the initial leaning of the group, and this predominance of arguments leaning in one direction polarizes the opinions of the group members (Van Swol, 2009).  Supporting the predictions of persuasive arguments theory, research has shown that the number of novel arguments mentioned in discussion is related to the amount of polarization (Vinokur & Burnstein, 1978) and that there is likely to be little group polarization without discussion (Clark, Crockett, & Archer, 1971). Notice here the parallels between the persuasive arguments approach to group polarization and the concept of informational conformity.

But group polarization is in part based on the affective responses of the individuals—and particularly the social identity they receive from being good group members (Hogg, Turner, & Davidson, 1990; Mackie, 1986; Mackie & Cooper, 1984). The idea here is that group members, in their desire to create positive social identity, attempt to differentiate their group from other implied or actual groups by adopting extreme beliefs. Thus the amount of group polarization observed is expected to be determined not only by the norms of the ingroup but also by a movement away from the norms of other relevant outgroups. In short, this explanation says that groups that have well-defined (extreme) beliefs are better able to produce social identity for their members than are groups that have more moderate (and potentially less clear) beliefs. Once again, notice the similarity of this account of polarization to the notion of normative conformity.

Group polarization effects are stronger when the group members have high social identity (Abrams, Wetherell, Cochrane, & Hogg, 1990; Hogg, Turner, & Davidson, 1990; Mackie, 1986). Diane Mackie (1986) had participants listen to three people discussing a topic, supposedly so that they could become familiar with the issue themselves to help them make their own decisions. However, the individuals that they listened to were said to be members of a group that they would be joining during the upcoming experimental session, members of a group that they were not expecting to join, or some individuals who were not a group at all. Mackie found that the perceived norms of the (future) ingroup were seen as more extreme than those of the other group or the individuals, and that the participants were more likely to agree with the arguments of the ingroup. This finding supports the idea that group norms are perceived as more extreme for groups that people identify with (in this case, because they were expecting to join it in the future). And another experiment by Mackie (1986) also supported the social identity prediction that the existence of a rival outgroup increases polarization as the group members attempt to differentiate themselves from the other group by adopting more extreme positions.

Taken together then, the research reveals that another potential problem with group decision making is that it can be polarized. These changes toward more extreme positions have a variety of causes and occur more under some conditions than others, but they must be kept in mind whenever groups come together to make important decisions.

Social Psychology in the Public Interest

Decision Making by a Jury

Although many countries rely on the decisions of judges in civil and criminal trials, the jury is the foundation of the legal system in many other nations. The notion of a trial by one’s peers is based on the assumption that average individuals can make informed and fair decisions when they work together in groups. But given all the problems facing groups, social psychologists and others frequently wonder whether juries are really the best way to make these important decisions and whether the particular composition of a jury influences the likely outcome of its deliberation (Lieberman, 2011).

As small working groups, juries have the potential to produce either good or poor decisions, depending on many of the factors that we have discussed in this chapter (Bornstein & Greene, 2011; Hastie, 1993; Winter & Robicheaux, 2011). And again, the ability of the jury to make a good decision is based on both person characteristics and group process. In terms of person variables, there is at least some evidence that the jury member characteristics do matter. For one, individuals who have already served on juries are more likely to be seen as experts, are more likely to be chosen as jury foreperson, and give more input during the deliberation (Stasser, Kerr, & Bray, 1982). It has also been found that status matters—jury members with higher-status occupations and education, males rather than females, and those who talk first are more likely to be chosen as the foreperson, and these individuals also contribute more to the jury discussion (Stasser et al., 1982). And as in other small groups, a minority of the group members generally dominate the jury discussion (Hastie, Penrod, & Pennington, 1983). There is also frequently a tendency toward social loafing in the group (Najdowski, 2010). As a result, relevant information or opinions are likely to remain unshared because some individuals never or rarely participate in the discussion.

Perhaps the strongest evidence for the importance of member characteristics in the decision-making process concerns the selection of death-qualified juries in trials in which a potential sentence includes the death penalty. In order to be selected for such a jury, the potential members must indicate that they would, in principle, be willing to recommend the death penalty as a punishment. In some countries, potential jurors who indicate being opposed to the death penalty cannot serve on these juries. However, this selection process creates a potential bias because the individuals who say that they would not under any condition vote for the death penalty are also more likely to be rigid and punitive and thus more likely to find defendants guilty, a situation that increases the chances of a conviction for defendants (Ellsworth, 1993).

Although there are at least some member characteristics that have an influence upon jury decision making, group process, as in other working groups, plays a more important role in the outcome of jury decisions than do member characteristics. Like any group, juries develop their own individual norms, and these norms can have a profound impact on how they reach their decisions. Analysis of group process within juries shows that different juries take very different approaches to reaching a verdict. Some spend a lot of time in initial planning, whereas others immediately jump right into the deliberation. And some juries base their discussion around a review and reorganization of the evidence, waiting to take a vote until it has all been considered, whereas other juries first determine which decision is preferred in the group by taking a poll and then (if the first vote does not lead to a final verdict) organize their discussion around these opinions. These two approaches are used about equally often but may in some cases lead to different decisions (Hastie, 2008).

Perhaps most important, conformity pressures have a strong impact on jury decision making. As you can see in Figure 10.9, when there are a greater number of jury members who hold the majority position, it becomes more and more certain that their opinion will prevail during the discussion. This is not to say that minorities cannot ever be persuasive, but it is very difficult for them. The strong influence of the majority is probably due to both informational conformity (i.e., that there are more arguments supporting the favored position) and normative conformity (people are less likely to want to be seen as disagreeing with the majority opinion).

This figure shows the decisions of six-member mock juries that made “majority rules” decisions. When the majority of the six initially favored voting guilty, the jury almost always voted guilty, and when the majority of the six initially favored voting innocent, the jury almost always voted innocence. The juries were frequently hung (could not make a decision) when the initial split was three to three. Data are from Stasser, Kerr, and Bray (1982).

Research has also found that juries that are evenly split (three to three or six to six) tend to show a leniency bias by voting toward acquittal more often than they vote toward guilt, all other factors being equal (MacCoun & Kerr, 1988). This is in part because juries are usually instructed to assume innocence unless there is sufficient evidence to confirm guilt—they must apply a burden of proof of guilt “beyond a reasonable doubt.” The leniency bias in juries does not always occur, although it is more likely to occur when the potential penalty is more severe (Devine et al., 2004; Kerr, 1978).

Given what you now know about the potential difficulties that groups face in making good decisions, you might be worried that the verdicts rendered by juries may not be particularly effective, accurate, or fair. However, despite these concerns, the evidence suggests that juries may not do as poorly as we would expect. The deliberation process seems to cancel out many individual juror biases, and the importance of the decision leads the jury members to carefully consider the evidence itself.