Post-decision consolidation: group members in different social settings compared to individual decision makers

Two experiments were conducted to examine how making decisions in a 3-member group affects the degree of post-decision consolidation, defined as attractiveness changes in favor of the chosen alternative. Both experiments were conducted in two sessions one week apart. In the first session (decision phase), participants estimated the importance of each of four different attributes describing two decision alternatives. They were then shown predetermined attractiveness ratings on each of the attributes and were to decide on the two alternatives, either individually or as a group. In the second session (post-decision phase), the participants were to attempt to recall the attractiveness ratings for the attributes as presented to them in session one. In both experiments, significant post-decision consolidation was found for individual decision makers but not for group members. In experiment 2, this result was replicated, no difference in consolidation being found between group members with face-to-face interaction and without.     

Post-decision consolidation in large group decision-making

Decision-makers tend to change the psychological attractiveness of decision alternatives in favor of their own preferred alternative after the decision is made. In two experiments, the present research examined whether such decision consolidation occurs also among individual group members in a large group decision-making situation. High-school students were presented with a decision scenario on an important issue in their school. The final decision was made by in-group authority, out-group authority or by majority after a ballot voting. Results showed that individual members of large groups changed the attractiveness of their preferred alternative from a pre- to a post-decision phase, that these consolidation effects increased when decisions were made by in-group members, and when participants identified strongly with their school. Implications of the findings for understanding of group behavior and subgroup relations are discussed.     

Individual postdecision processes in group settings

In two experiments Differentiation and Consolidation Theory (Diff Con) (Svenson, 1992) was used to investigate individual postdecision making processes in three-member groups. It was predicted that in groups in which the subjects preferred different alternatives (conflict groups), subjects would consolidate their own preferred alternative, and not the group's final decision. A second hypothesis was that no consolidation would be indicated in groups in which all members preferred the same alternative (non-conflict groups). The results showed that in conflict groups, the members who gave up their preferred alternative (minority members) consolidated their own preference, thereby significantly regretting the group decision. In contrast, members who got their own will through in the majority decision (majority members) showed no consolidation of the group decision. The corresponding pattern of results was replicated in a second experiment, using a different decision situation. The results indicated that perceptions of social support, agreement in a group and decreasing responsibility for a group's decision, could all partly substitute consolidation by attractiveness restructuring.     

From individual preference construction to group decisions: Framing effects and group processes

Two choice tasks known to produce framing effects in individual decisions were used to test group sensitivity to framing, relative to that of individuals, and to examine the effect of prior, individual consideration of a decision on group choice. Written post-decision reasons and pre-decision group discussions were analyzed to investigate process explanations of choices made by preexisting, naturalistic groups. For a risky choice problem, a similar framing effect was observed for groups and individuals. For an intertemporal choice task where consumption was either delayed or accelerated, naïve groups (whose members had not preconsidered the decision) showed a framing effect, less discounting in the delay frame, opposite to that observed in individuals. Predecided groups showed a non-significant effect in the other, expected direction. In all cases, process measures better explained variability in choices across conditions than frame alone. Implications for group decision research and design considerations for committee decisions are addressed.     

个体自信度对双人决策的影响

群体决策是重要的社会现象, 个体自信度在群体决策中发挥了重要作用。本文开展了不同难度和信息交流方式下的双人决策实验, 通过分析自信度和个体决策以及决策调整行为的关系, 研究了个体自信度的交流对双人决策的影响。实验结果表明, 个体的自信度与选择的正确率高度正相关; 双人决策过程是个体根据对方的自信度和选择来不断调整自己的选择最终达成一致的过程, 并通过交互过程提高双人决策的正确率; 实验中双人决策的质量明显优于“自信度分享模型”和“更自信者主导决策模型”的预期结果, 表明群体决策不是通过分享自信度进行的贝叶斯优化整合过程, 也不是由更自信的个体完全主导的过程。     

Post-decision consolidation over time as a function of gain or loss of an alternative

Post-decision consolidation processes were studied in a two-stage lottery design. School children (1) rated the attractiveness of audiotape head sets, (2) decided for which of two head sets they would like to get a lottery ticket, (3) threw a dice to determine if they got a lottery ticket in the preferred lottery or not, and (4)drew a ticket in the final lottery. Before and after each of these stages ratings were obtained of the attractiveness of the alternatives on four attributes. The results were interpreted in terms of Differentiation and Consolidation Theory. Post-decision consolidation appeared immediately after the outcome of the dice throw. Subjects who won a lottery ticket consolidated their prior decision to a greater degree than those who lost. The effect was so strong for the former group that a pre-decision attractiveness disadvantage was restructured to a post-decision advantage. Folowing the decision, consolidation remained at approximately the level reached immediately after the dice throw for losers and winners, respectively, but with an increasing trend over time for winners. Even following a final loss of an audiotape headset the level of consolidation was maintained.     

Do the right thing: The assumption of optimality in lay decision theory and causal judgment

Human decision-making is often characterized as irrational and suboptimal. Here we ask whether people nonetheless assume optimal choices from other decision-makers: Are people intuitive classical economists? In seven experiments, we show that an agent’s perceived optimality in choice affects attributions of responsibility and causation for the outcomes of their actions. We use this paradigm to examine several issues in lay decision theory, including how responsibility judgments depend on the efficacy of the agent’s actual and counterfactual choices (Experiments 1–3), individual differences in responsibility assignment strategies (Experiment 4), and how people conceptualize decisions involving trade-offs among multiple goals (Experiments 5–6). We also find similar results using everyday decision problems (Experiment 7). Taken together, these experiments show that attributions of responsibility depend not only on what decision-makers do, but also on the quality of the options they choose not to take.     

Biased information search in group decision making

Research has shown that people prefer supporting to conflicting information when making decisions. Whether this biased information search also occurs in group decision making was examined in three experiments. Experiment 1 indicated that groups as well as individuals prefer supporting information and that the strength of this bias depends on the distribution of the group members' initial decision preferences. The more group members had chosen the same alternative prior to the group discussion (group homogeneity), the more strongly the group preferred information supporting that alternative. Experiment 2 replicated these results with managers. Experiment 3 showed that the differences between homogeneous and heterogeneous groups reflect group-level processes. Higher commitment and confidence in homogeneous groups mediated this effect. Functional and dysfunctional aspects of biased information seeking in group decision making are discussed.     

Effects of group decision rules on decisions involving continuous alternatives: The unanimity rule and extreme decisions in mock civil juries

Two experiments examined the effects of majority and unanimity decision rules on group decisions involving continuous alternatives. Each experiment used mock civil juries to test three hypotheses related to the claim that when the distribution of group members’ initial preferences is skewed, the group’s decision will be influenced more by the presence of outlier members under unanimity rule than under majority rule. Experiment 1 tested the hypotheses using a punitive damages case and positively skewed preference distributions. Experiment 2 tested the hypotheses using a compensatory damages case and manipulating the skewness of preference distributions in a 2 (group decision rule) × 2 (valence of skewness) factorial design. In both experiments, the extreme (outlier) member’s individual preference was significantly correlated with the group decision only under unanimity rule. A simple thought experiment based on the experimental results is suggested regarding the implications of using unanimity or majority rule for making decisions in civil juries.     

Group decision process and incrementalism in organizational decision making

In two studies examining resource allocation, support is found for the notion that group decisions are affected in systematic ways depending on whether or not there was individual consideration of the problem before meeting as a group. Specifically, compared to no prior consideration groups, prior consideration groups (1) escalate their commitment more in progress (i.e., ongoing) decisions, and (2) are less willing to concentrate resources on a single project in adoption (i.e., resource utilization) decisions. The findings challenge the blanket assertion that promoting divergent views in a group decision context is always related to better decisions.     

Recognition is used as one cue among others in judgment and decision making

Three experiments with paired comparisons were conducted to test the non-compensatory character of the recognition heuristic (D. G. Goldstein & G. Gigerenzer, 2002) in judgment and decision making. Recognition and knowledge about the recognized alternative were manipulated. In Experiment 1, participants were presented pairs of animal names where the task was to select the animal with the larger population. In Experiment 2, participants chose the safer 1 out of 2 airlines, and 3 knowledge cues were varied simultaneously. Recognition effects were partly compensated by task-relevant knowledge. The compensatory effects were additive. Decisions were slower when recognition and knowledge were incongruent. In Experiment 3, compensatory effects of knowledge and recognition were found for the city-size task which had originally been used to demonstrate the non-compensatory character of the recognition heuristic. These results suggest that recognition information is not used in an all-or-none fashion but is integrated with other types of knowledge in judgment and decision making.     

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.     

任务重要性对决策策略有效性的影响

研究以选择决策中决策任务的主观性为关注点,通过现场和实验室两项实验考察决策任务重要性对启发式和分析式策略有效性的影响。结果发现,在感知任务重要的情况下,采用分析式策略的被试决策后满意度高于采用启发式策略的被试;在感知任务不重要情况下,采用启发式策略的被试决策后满意度高于采用分析式策略的被试。研究表明,决策者感知到的任务重要与否会影响启发式和分析式两种决策策略的效果。     

Holistic Information Integration in Child Decision Making

Weighted‐additive (WADD) strategies require decision makers to integrate multiple values weighted by their relevance. From what age can children make choices in line with such a WADD‐strategy? We compare multi‐attribute decisions of children (6–7; 8–10; 11–12‐year‐olds) with adults in an open information‐board environment without pre‐decisional information search. In two experiments, we classify decision strategies based on individual choice patterns and find that in all age groups the majority of participants are users of a WADD‐strategy. Simple decision heuristics such as lexicographic strategies were applied rarely by children and not at all by adults. In two additional follow‐up studies, we further investigate the underlying process of WADD‐application by analysing decision latencies in combination with a retrospective think‐aloud study. Results suggest that children did not apply WADD‐strategies in a deliberate fashion in our experiments. Overall, our findings demonstrate that the ability to make good and quick decisions by holistically integrating information is already present in young children. Copyright © 2017 John Wiley & Sons, Ltd.     

Postdecision consolidation in a trend prediction task

To be able to learn from experience it is necessary to correctly apprehend experienced feedback and the situation in which it is provided. The results indicate how post-decision consolidation in complex domains may affect learning. The problem may be particularly pertinent in recurrent decision making where considerable risk is involved. The study explores the changes in aspect (signal) importance from pre- to postdiction as a function of outcome information. By postdiction we mean the remembering of an earlier prediction (cf. Hawkins & Hastie, 1990). Subjects were asked to decide on which of four alternative future price developments would follow a historical price trajectory for different commodities, and to rate the importance of each of the chosen alternative's corresponding aspects. The subjects revealed a bias in their support ratings of aspects--seeing support in aspects that traditionally (by themselves and in many contexts) would be seen as neutral or even counter-indicative of the alternative chosen. After an intermission, the subjects were also given information about what was indicated to be the actual development of the market. One group was told that their decisions were correct (irrespective of what the decisions were), another group that they were incorrect but close, a third group that they were incorrect by far, while a fourth group served as a control. Following this information the subjects were again asked to judge the importance of the aspects for their own prior decision on the most likely future development. The results indicated that outcome feed-back had an effect on post decision restructuring of facts. Subjects in the correct condition showed an average consolidation that increased the support, while the wrong conditions lead to negative consolidation (in retrospect indicating that they never found as much support for their decision in the past as they actually did). Thus, in a choice between consolidating their own initial prediction and the price trajectory they would have to live with, the decision makers consolidated the outcome. Therefore, the results of the study were related to the hindsight bias phenomenon (Fischhoff, 1975) and to Kahneman and Miller's (1986) mutability concept.     

Intergroup trust and reciprocity in strategic interactions: Effects of group decision-making mechanisms

I examined the impact of the consensus-making mechanism, where members reach a common decision via an intra-group discussion, on intergroup trust and reciprocity in a strategic setting. Data from a trust game generated the following results. First, compared to individual decision-makers, consensus groups exhibited (a) lower psychological trust, (b) higher behavioral trust, after controlling for psychological trust, and (c) lower reciprocity. Second, compared to decisions made by group-representatives, who are responsible for unilateral decisions on behalf of their groups, group consensus decisions were more trusting but less reciprocating. Thus, the specific decision-making mechanism adopted by groups in a strategic interaction may profoundly change the nature and the interplay of the interaction. Lastly, results show that the level of behavioral trust is driven by reciprocity expectations, while the level of reciprocity behavior, measured as a proportion of the trust received, does not change systematically with the level of trust experienced.     

Utilizing probabilities as decision weights in closed and open information boards: A comparison of children and adults

Decisions in preschoolers (6 years), elementary schoolers (9.7 years), and adults (21 years) were studied with an information board crossing three probabilistic cues (validities: .83, .67, .50) with two options. Experiment 1 (n = 215) applied a standard version of the information board (closed presentation format), in which information must be searched sequentially and kept in mind for the decision. Experiment 2 (n = 217) applied an open format (Glöckner & Betsch, 2008), in which all information was visible during decision making. Elementary schoolers but not preschoolers benefited from an open format — indicated by an increase in using probabilities as decision weights. In the open but not closed format, choices were biased by normatively irrelevant information (the lure). Variations in the prediction patterns of the cues influenced decisions in all age groups. Effects for presentation format, pattern, and lure jointly indicate that even children are capable of considering multiple information in their decisions.     

Accounting and convincing: the effect of two types of justification on the decision process

The effect of two types of justification pressure on the decision process was investigated. Three groups of 15 subjects each had to choose the head of a corrective home for criminal adolescents out of six candidates, who were described on 16 attributes. Two groups worked under justification pressure: subjects in the Accounting group were informed that they had to explain their decision afterwards, subjects in the Convincing group that they had to convince the other members of the executive board to vote for their selected candidate. From the third group, no justification was requested. It was found that justification pressure leads to a distinct increase in the amount of utilized information and to a more elaborate choice process, while the global decision heuristics do not seem to change. The two justification groups did not differ in the amount of information utilized, but the Convincing group employed a more elaborate process. This result shows that justification pressure is one of the task characteristics affecting the decision process, and proves that a latent justification pressure as assumed in some decision theories does not have the same effect as an explicit one. Copyright © 2001 John Wiley & Sons, Ltd.     

Ostracism Reduces Reliance on Poor Advice from Others during Decision Making

Decision making is rarely context‐free, and often, both social information and non‐social information are weighed into one's decisions. Incorporating information into a decision can be influenced by previous experiences. Ostracism has extensive effects, including taxing cognitive resources and increasing social monitoring. In decision making situations, individuals are often faced with both objective and social information and must choose which information to include or filter out. How will ostracism affect the reliance on objective and social information during decision making? Participants (N = 245) in Experiment 1 were randomly assigned to be included or ostracized in a standardized, group task. They then performed a dynamic decision making task that involved the presentation of either non‐social (i.e. biased reward feedback) or social (i.e., poor advice from a previous participant) misleading information. In Experiment 2, participants (N = 105) completed either the ostracism non‐social condition or social misleading information condition with explicit instructions stating that the advice given was from an individual who did not partake in the group task. Ostracized individuals relied more on non‐social misleading information and performed worse than included individuals. However, ostracized individuals discounted misleading social information and outperformed included individuals. Results of Experiment 2 replicated the findings of Experiment 1. Across two experiments, ostracized individuals were more critical of advice from others, both individuals who may have ostracized them and unrelated individuals. In other words, compared with included individuals, ostracized individuals underweighted advice from another individual but overweighed non‐social information during decision making. We conclude that when deceptive objective information is present, ostracism results in disadvantageous decision making. Copyright © 2015 John Wiley & Sons, Ltd.     

Test of a Level of Aspiration model of group decision making: Non-obvious group preference reversal due to an irrelevant alternative

We conducted two experiments that investigated a non-obvious prediction of a Level of Aspiration (LOA) model of group decision making. In both experiments, groups chose among three alternatives, A, B, and C, with C always being least preferred by all of the group members. In each experiment, by manipulating the nature of alternative C, we created two conditions differing in whether only A or only B was acceptable to all members. In support of the LOA model, groups tended to choose the alternative acceptable to all members, even when (Experiment 2) a majority of members most preferred a different alternative. Implications of the results for the LOA model are discussed in the context of social choice theory.