• Why make decisions in group?• What problems undermine the effectiveness

of decision-making in groups?• Why do groups make riskier decisions than

individuals?• What is groupthink, and how can it be

prevented?

Why people rely on groups?

• Being better at choosing, judging, estimating, and problem solving

• Forming more accurate perceptions of people

• Making more accurate diagnosis (physicians)

• Getting better grades (students)

Majorie E. Shaw (1932)

• Participants: 21 individuals and five 4-person groups

• Task: missionary-cannibal dilemma• Procedure:

work alone work in groupwork in group work alone

• Three missionaries and three cannibals are on one side of the river and want to cross to the other side by means of a boat that can only hold two persons at a time. All the missionaries can row, but only one cannibal can row. For obvious reasons, the missionaries must never be outnumbered by the cannibals, under any circumstances or at any time, except where no missionaries are present at all. How many crossings will be necessary to transport the six people across the river?

Marjorie E. Shaw’s Finding (1932)

0

10

20

30

40

50

60

1st Set 2nd Set

groupsindividuals

• Groups generated more correct solutions

• Groups were better at detecting errors

• Groups made mistakes later than did individuals

• Groups took longer to complete the task

Per

cent

age

Cor

rect

Groups do not perform well when

• tasks are very difficult, complex, unfamiliar, uninteresting

• time is limited• performing judgmental tasks (compared to

intellective tasks)

OrientationDefining the

problemPlanning the

processDiscussion

Remembering informationExchanging informationProcessing information

Decision MakingChoosing group

solutions

ImplementationAdhering to

the decisionEvaluating the

decision

A functional model of group decision making

Orientation

• The development of a shared mental model that they rely on throughout the rest of the meeting

• Group members rarely show much interest in process planning

Discussion

• A collective information processing approach to decision making assume that people seek out and process relevant information during the group discussion

• Three information processing gains from discussion are– improved memory for information– increased information exchanged– more thorough processing of information

What is the value of discussion?

Groups have superior memories for

information relative to individuals• Groups have better informational

resources than individuals--collective memory

• Cross-cuing improves group memories• Groups enhance their collective

memories by creating transactive memory systems that effectively divide up information among members

Groups have more information than do individuals

• Some members may know a great deal about tasks or some relevant information

• Groups can get more information

Groups process the information they have more

thoroughly through discussion• Members ask questions and others offer

answers• Members discuss alternative options,

considering the strength and weakness of each option

Deciding

• A social decision scheme – implicit scheme

• Truth-wins rule (adopting the correct answer as the group solution)

• Majority-rules model (selecting a decision favored by more than 50% of group members)

Deciding

• A social decision scheme– Explicit scheme

• Delegating decisions• Statisticized decisions• Plurality decisions (voting, ranking)• Unanimous decisions (consensus)• Random decisions (chance)

Implementation

• Implementing the decision• Evaluating the decision• Involving in planning is important

Vroom’s normative model of decision making

• Different types of situations call for different types of decision-making methods– Autocratic I– Autocratic II– Consultative I– Consultative II– Group II

5 basic types of decision-making process (Vroom, 2003)

• Decide: leader solves the problem or makes the decision and announces it to the group

• Consult (Individual): leader shares the problem with group members individually, then the leader makes the decision

• Consult (Group): leader discusses the problem with members as a group, then leader makes the decision

5 basic types of decision-making process (Vroom, 2003)

• Facilitate: leader collaborates with group members, helping the group to reach consensus, accepting the decision that is supported by the entire group

• Delegate: group reaches a decision without the leader’s involvement. The leader provides support, direction, clarification, and resources.

Problems when groups make decisions• Poor communication

skills• Egocentric behavior• Nonparticipation• Sidetracked• Interruptions • Negative leadership

behavior• Negative attitudes and

emotions

What Problems Undermine the Effectiveness of

Decision-Making Groups? • Group discussion pitfalls

– Information processing limitations: leveling, assimilation, sharpening

– Poor communication skills– Decisional avoidance (procrastination,

bolstering, denying responsibility, satisficing)

Tactics used during discussion to avoid making a decision• The group postpones the decision

• Formulating a decision without thinking things through… exaggerating the favorable consequences and minimizing the importance and likelihood of unfavorable consequences

• Avoiding responsibility by delegating the decision to a subcommittee or by diffusing accountability throughout the entire assemblage

• Ignoring alternatives… considering only the narrow range of policy alternatives that differ very little from the existing policy• Accepting any solution that meets the minimal set of criteria instead of finding the best solution• Avoid dealing with the larger issues by focusing on minor issues• Sometimes decisions demand too much cognitive work from members

What Problems Undermine the Effectiveness of Decision-Making Groups?

• Shared information bias – Oversampling shared information leads to poorer

decisions when a hidden profile would be revealed by considering the unshared information more closely

– Stasser and Titus (1985)’s experiment– Informational and normative influence cause this bias– Factors that increase (leadership style) and decrease

(using a GDSS) the bias

What Problems Undermine the Effectiveness of Decision-Making Groups?

• Judgment errors and heuristic biases – Sins of omission and commission– Sins of imprecision: Heuristics

When and why do groups make poor decisions?

• Groups spend more time discussing shared information rather than unshared information

• Unshared information, although inadequately discussed, still influences judgment

• The best decision will go unrecognized if members fail to pool their unshared information

• An effective discussion leader can prompt members to reveal unshared information and keep the group’s attention focused on that information by repeating it during the discussion

Social decision theory: Group wh ose members are initially more risk

prone than cautious seem to adopt - a “risk supported wins” scheme. If

more than one member favors the r isky alternative, the group will ado

pt it. When the majority members l ean toward the cautious pole, the g -roup seems to adopt a “cautious su

pported wins” scheme. If two mem bers support conservative solution,

the group chooses that alternative

Group polarization• Groups’ decisions tend to be more

extreme than individuals’ decisions• Risky shift vs. cautious shift is founded• Group polarization hypothesis: the

average postgroup response will tend to be more extreme in the same direction as the average of the pregroup responses

What causes polarization?

• Social comparison theory (value hypothesis): When individuals discuss their opinions in a group, they shift in the direction that they think is consistent with the values of their group or culture

• Persuasive-argument theory: If discussion exposes the individual to persuasive arguments that favor Position A, the person will shift in that direction. If the discussion generates more anti A argument, the individual will shift in that direction

Groupthink Symptoms of Groupthink

• Interpersonal pressures make agreeing too easy and disagreeing too difficult

• Members privately felt uncertain about the plan, -- -but they kept their doubts to themselves self ce

nsorship• Someone appointed himself/herself as a guard to

protect members from information that they thin --k will disrupt the group mindguards

• Each member wrongly concludes that everyone e lse liked the plan, so no objections surfaced durin

-- g the discussion apparent unanimity

• Members felt that they were performing well -- , even though they were not illusion of invulnerability

• Decision makers lose their moral thought in -- the group’s desire to win illusion of morality

• Group members expressed their biased perc eptions of the outgroup during the discussio

n• Decision are inadequate

Causes of groupthink• Cohesiveness• -- Isolation no outsiders participate in the discuss

ion• -- Leadership the leader completely controlled th

e group discussion, made his opinion clear at th e outset of each meeting, suppressed any disse

nting opinions, required a voice vote by each m ember without prior group discussion

• The group coped with the stress when making a major decision by minimizing argument or disse nsion, maximizing the positive consequences

How to prevent groupthink?

• Limiting a premature seeking of concurrence• Correcting group members’ misperceptions

and biases• Using effective decision-making technique