The Rank-Order Effect in Group Decision Making

Many studies indicate that group discussion candisproportionately reflect information known by all group members,at the expense of information known to only one group member, andthis is associated with suboptimal group decisions (Stasser &Titus, 1985). The present study examined the impact of threeprocedural factors on information sharing and quality of groupdecision: (a) group decision procedure (an instruction to "rankorder the alternatives" vs "choose the best alternative"), (b)information access during group discussion (reliance on memory vscomplete access), and (c) communication technology (computer vsface to face). Three-person groups worked on an investment decisionthat was structured as a hidden-profile task where criticalinformation was distributed unevenly prior to group discussion. Thedata provided support for a rank-order effect: Groups instructedto rank order the alternatives, compared to groups instructed tochoose the best alternative, were more likely to fully consider allof the alternatives, exchange information about unpopularalternatives, and make the best decision. But these effects onlyoccurred in face-to-face groups. In computer-mediated groups, therewas general information suppression and no effect of group decisionprocedure. Access to information during group discussion increaseddiscussion of both unique and common information, in theface-to-face conditions, but had no effect on group decisionquality. Taken together, the data suggest that procedural aspectsof group discussion may help overcome the impact of prediscussionpreferences on information processes and group decision.     

The Collective Preference for Shared Information

Decision-making groups prefer to discuss shared information that all members know instead of unshared information that a single member knows. This bias toward discussing shared information can lead groups to make suboptimal decisions when unshared information is critical for good decision making. This preference for discussing shared information may stem from group members' positive evaluations of each other's task capabilities when shared information is communicated. Members who already are perceived as capable (i.e., those high in status, experts, and leaders) need not bolster their image by communicating shared information. Instead, they discuss unshared information more than members perceived as less capable. As members low in status gain respect by communicating shared information, they may risk mentioning unshared information later during discussion. Assigning group leaders, informing members of their expert roles, and allowing ample time for discussion may increase groups' discussion of unshared information.     

Information sampling and group decision making: the effects of an advocacy decision procedure and task experience

Group discussions tend to focus on information that was previously known by all members (shared information) rather than information known by only 1 member (unshared information). If the shared information implies a suboptimal alternative, this sampling bias is associated with inaccurate group decisions. The present study examines the impact of 2 factors on information exchange and decision quality: (a) an advocacy group decision procedure versus unstructured discussion and (b) task experience. Results show that advocacy groups discussed both more shared and unshared information than free-discussion groups. Further, with increasing experience, more unshared information was mentioned in advocacy groups. In contrast, there was no such increase in unstructured discussions. Yet advocacy groups did not significantly improve their decision quality with experience.     

自由讨论条件下群体决策质量的影响因素

通过实验室实验考察了自由讨论条件下群体决策质量的影响因素,并对Stasser所提出的信息取样模型进行了验证,结果发现：(1)部分证实Stasser的信息取样模型。在信息不分享的条件下,如果讨论前群体成员的偏好比较一致时,群体的确倾向于讨论分享信息和群体所偏好的候选人的信息;但如果讨论前的偏好不一致或任务难度较低时,这一结论难以成立。(2)自由讨论条件下,群体规模的增加会增加分享信息的讨论量,而对非分享信息的讨论程度则无显著影响。而在任务难度方面,只有任务难度较大的情况下才有分享信息的讨论优势。     

Improving group decisions by better pooling information: a comparative advantage of group decision support systems

This study compared a group decision support system (GDSS) with face-to-face (FTF) group discussion on characteristics of information exchange and decision quality. Participants given conflicting information tended to share more of their unique data and engaged in more critical argumentation when using the GDSS than when meeting FTF. Conversely, when information was consistent among members, there were no such differences between FTF and GDSS groups. The GDSS groups significantly outperformed the FTF groups in agreeing on the superior hidden profile candidate, especially when there was a lack of prediscussion consensus. Individual-level analyses revealed that members of GDSS groups that did not have a prediscussion consensus tended to experience stronger preference shifts toward the group's consensus decision.     

The dissemination of critical,unshared information in decision‐making groups: the effects of pre‐discussion dissent

Previous research in group decision making has found that in situations of a hidden profile (i.e. the best choice alternative is hidden from individual members as they consider their pre‐discussion information), unshared information is disproportionately neglected and sub‐optimal group choices are highly likely. In an experimental study, three‐person groups decided which of three candidates to select for a professorial appointment. We hypothesised that minority dissent in pre‐discussion preferences improves the consideration of unshared information in groups and increases the discovery rate of hidden profiles. As predicted, consideration of unshared information increased with minority dissent. The expectation of an improvement of group decision quality was partially supported. In diversity groups (i.e. each member prefers a different alternative) consideration of unshared information and group decision quality was significantly higher than in simple minority groups. Results are discussed in the light of theories of minority influence. The benefits of using the hidden profile paradigm with minority and diversity groups for theory development in the area of group decision making are highlighted. Copyright © 2002 John Wiley & Sons, Ltd.     

多决策方法多交流方式的群体决策比较

采用人员选拔的实验室模拟实验,以160名被试组成40个4人群体,对4种决策方法和2类交流方式的群体决策进行了比较。结果发现（1）决策方法和交流方式对于讨论过程的信息交流具有显著影响;（2）以计算机为中介进行决策的被试知觉到的任务难度要高于面对面决策条件;决策方法对于群体成员有关实验任务难度知觉具有主效应;交流方式和决策方法对于群体决策过程满意感和结果满意感没有显著影响;（3）在以投票轮次来表明群体达成一致意见所需时间上,决策方法对于投票轮次具有显著影响。恶魔式辩护、辨证式查询两种方法下所需的投票轮次多于专家意见法和自由讨论法的投票轮次。     

面对面和计算机群体决策运用排序法上的比较

通过人员选拔的实验室模拟实验．比较面对面的和以计算机为中介的决策群体在信息是否完全分享及是否采用排序法决策条件下对于决策效标的影响。结果表明：(1)决策前的信息分享通过决策前偏好的人数构成影响了最终的决策准确率。(2)排序法在面对面交流时只在信息非分享的情况下才显著增加了关键信息交流;排序法在计算机交流和信息完全分享下显著增加了关键信息交流。弥补了Hollingshead的研究不足之处。排序法不损害成员对于讨论的满意感。(3)计算机交流更关注文本信息,有更多争论、自我观点阐述和申诉。在关键信息交流上与面对面交流没有差异。(4)在决策准确性上,不同的交流方式没有差异。     

Who’s bringing the donuts: The role of affective patterns in group decision making

Two studies examined how intragroup affective patterns influence groups’ pervasive tendency to ignore the unique expertise of their members. Using a hidden profile task, Study 1 provided evidence that groups with at least one member experiencing positive affect shared more unique information than groups composed entirely of members experiencing neutral affect. This occurred because group members experiencing positive affect were more likely to initiate unique information sharing, as well as information seeking. Study 2 built upon this base by showing that confidence mediates the relationship between positive affect and the initiation of unique information sharing. Additionally, Study 2 investigated the role of negative affect in group decision making and how negative and positive affect concurrently influence decision making when groups are composed of members experiencing each. The results are discussed in terms of the role affect plays in influencing group behavior and the resultant importance of investigating specific affective patterns.     

不同沟通方式下群体决策信息利用分析

以180名被试组成45个四人群体．完成模拟人事选拔的问题解决型任务,通过对群体决策过程的信息提取数量和提取次序的分析,考察不同的沟通方式和信息分享程度对群体决策信息利用的影响。结果表明。（1）在不同沟通方式下,决策成员的讨论前偏好对最终决策的影响很大。（2）在不同的沟通方式下,分享程度不同的信息在决策过程中的提取具有差异,体现了不同的规律。     

如何消除子团队的消极作用——子团队成员交换的作用

本文探究子团队层面的团队构成动态变化, 即子团队成员交换是否有助于消除子团队的消极影响。本文将存在两个平衡的以认同为基础的子团队的团队作为研究对象, 试图通过实验的研究方法来探讨子团队成员交换是否能够消除子团队对团队的消极影响。通过对75组子团队进行实验后发现: (1)相较于无子团队成员交换的团队, 有子团队成员交换的团队其团队信息深化及团队决策质量更佳; (2)团队信息深化在子团队成员交换与团队决策质量关系间呈中介作用。     

The effects of member expertise on group decision-making and performance

This study assesses the effects of member expertise on group decision-making and group performance. Three-person cooperative groups and three independent individuals solved either an easy or moderately difficult version of the deductive logic game Mastermind. Experimental groups were given veridical performance information, i.e., the members' rankings on prior individual administrations of the task. Control groups were not provided with this information. Results supported the predictions of this study: (1) groups gave more weight to the input of their highest performing members with the group decision-making process being best approximated by post hoc “expert weighted” social decision schemes and (2) groups performed at the level of the best of an equivalent number of individuals.     

Separating the confident from the correct: Leveraging member knowledge in groups to improve decision making and performance

Groups often struggle to distinguish expert members from others who stand out for various reasons but may not be particularly knowledgeable (Littlepage & Mueller, 1997). We examined an intervention designed to improve group decision making and performance through instructing group members to search for information they already possessed that was relevant to a problem. Participants estimated values and expressed their confidence in their estimates individually and then a second time either individually or in a group. This was done with or without the intervention. Results indicated that: (1) groups were more confident than, and out-performed, individuals, (2) group decision making was best captured by models predicting more influence for more accurate members when the intervention was used and more influence for more confident members in its absence, and (3) groups that received the intervention out-performed groups that did not.     

The Effect of Individual Difference Variables on Information Sharing in Decision‐Making Groups

We examined need for cognition, social desirability, and communication apprehension for their influence on the mention and repetition of shared and unshared information in 8‐person decision‐making groups. Both need for cognition and social desirability influenced the discussion of shared and unshared information in decision‐making groups. The findings indicate that increasing motivation to participate in group discussions may not help overcome the bias favoring shared over unshared information. Additionally, there are indications that social desirability increases the repetition of shared information. This finding is consistent with the idea of mutual enhancement (i.e., the idea that group members discuss shared information because it enhances their position with other group members).     

Modeling collective choice: decision‐making on complex intellective tasks

Three studies examined group problem‐solving on complex intellective tasks. In Study 1, a decision model proposed by Laughlin and Hollingshead ( 1995 ) provided the best fit to actual group choices. This study also compared three‐person group versus individual performance with time constrained and number of problems unconstrained, with individuals solving non‐significantly more problems and groups obtaining significantly superior trials‐to‐solution scores. In Study 2, one member of each group was given additional information on how to perform the task and member extroversion was measured. Neither factor significantly impacted the decision‐making process. In Study 3, task expertise was assessed prior to the group interaction. Results indicate that group members were twice as likely to adopt an option proposed by an expert compared to other group members. Together these studies demonstrate that group problem solving is governed jointly by qualities of the task and qualities of the group members. Copyright © 2006 John Wiley & Sons, Ltd.     

Group vs individual information processing: The effects of outcome feedback on decision making

Recent theories of individual decision making have emphasized the role of environmental feedback on decision performance and confidence. However, in relation to group decision making, feedback has received only minor attention. This study compared individual and group decision performance and confidence on a multicue personnel decision task under three different feedback conditions. Individuals and five-person groups decided whether to promote 48 different job candidates, and rated how confident they were in each of their decisions. Feedback as to the correctness of their decisions was provided after (a) every decision (Total Feedback), (b) only those decisions to promote the candidate (Partial Feedback), or (c) after none of the decisions (No Feedback). Results indicated that groups performed best under total feedback, while individuals performed best under partial feedback. In addition, greater amounts of feedback reduced individuals' confidence but had little effect on group member confidence. Implications for both current theory in decision making and group vs individual information processing are discussed.     

Social Identification and Interpersonal Communication in Computer‐Mediated Communication: What You Do Versus Who You Are in Virtual Groups

This study investigates the influence of interpersonal communication and intergroup identification on members’ evaluations of computer‐mediated groups. Participants (N= 256) in 64 four‐person groups interacted through synchronous computer chat. Subgroup assignments to minimal groups instilled significantly greater in‐group versus out‐group identification. One member in each group was instructed to exhibit interpersonally likable or dislikable behavior. Analysis revealed that confederates acting likably were more attractive than those acting dislikably regardless of their in‐group or out‐group status. Further results indicated that interpersonal behavior interacted with subgroup membership on identification shifts following online discussions. Interpersonal dynamics generally provided stronger effects on members in virtual groups than did intergroup dynamics, in contrast to predictions from previous applications of social identification to computer‐mediated communication.     

Decision Accuracy in Computer-Mediated versus Face-to-Face Decision-Making Teams

Changes in the way organizations are structured and advances in communication technologies are two factors that have altered the conditions under which group decisions are made. Decisions are increasingly made by teams that have a hierarchical structure and whose members have different areas of expertise. In addition, many decisions are no longer made via strictly face-to-face interaction. The present study examines the effects of two modes of communication (face-to-face or computer-mediated) on the accuracy of teams' decisions. The teams are characterized by a hierarchical structure and their members differ in expertise consistent with the framework outlined in the Multilevel Theory of team decision making presented by Hollenbeck, Ilgen, Sego, Hedlund, Major, and Phillips (1995). Sixty-four four-person teams worked for 3 h on a computer simulation interacting either face-to-face (FtF) or over a computer network. The communication mode had mixed effects on team processes in that members of FtF teams were better informed and made recommendations that were more predictive of the correct team decision, but leaders of CM teams were better able to differentiate staff members on the quality of their decisions. Controlling for the negative impact of FtF communication on staff member differentiation increased the beneficial effect of the FtF mode on overall decision making accuracy.     

Decision performance and diversity structure: Comparing faultlines in convergent,crosscut, and racially homogeneous groups

Group diversity structure (the composition of racial and job-function diversity) and pre-discussion decision effects on group decision accuracy were tested in three-person groups. Evidence supported the social categorization model and the notion of multiple faultlines (i.e., subgroup boundaries). Crosscut diversity structure, where racial and job-function subgroup boundaries are crossed, weakened faultlines, enhanced information sharing and improved decision-making. Our data also supported the common knowledge effect. Groups in which members made pre-discussion choices arrived at incorrect decisions consistent with majority members’ pre-discussion preferences, based on a biased subset of information. Crosscut groups in which members did not make pre-discussion choices performed the best. Analyses of video taped interactions and attitudes toward the group help to explain these differences. We discuss the implications for managing demographically diverse groups and for future research on the impact of various attributes of diversity in groups.     

Persuasive Arguments Theory A Test of Assumptions

Persuasive Arguments Theory (PAT) is a noninteractionl theory of group decision making that predicts decision outcomes from the cognitive arguments individuals generate prior to discussion. PAT proponents do not view discussion as a crucial determinant of decision outcomes, but rather as one possible medium for information exchange. On this view, they assume members’ cognitive arguments correspond to arguments produced in discussion and group influence is a function of these stable structures produced outside interaction. As part of a larger research program undertaken to evaluate PAT, this article assesses PAT assumptions about argument and argument influence. Following a review and critique of PAT, five hypotheses are advanced to test its assumptions. Results revealed little correspondence between cognitive and discussion arguments in number, content, or persuasiveness. Additionally, PAT assumptions about argument influence were not supported. Implications for PAT and for the role of communication in group decision making are discussed.