“Social Influence”
Chapter 7
How do group members influence
one another’s opinions?
Overview
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Group Polarization
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General Social Influence Theories
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No Social Influence (social decision schemes)
Opinion Expression (social comparison)
New Information (persuasive arguments)
Opinion Expression and New Information
Structurational Theory (group discussion)
The Valence Model
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Risky Shift
Cautious Shift
Universal Social Influence Theory
Threshold Levels
General Propositions & Conclusions
Critical Background Information
 Focus
shifts from group structure (e.g.,
power, conformity & deviance) to process
(social influence and group interaction).
 Natural (bona fide) groups vs. contrived
(zero history) groups
 Effects of Social Influence – how do
individual opinions somehow become
“transformed” into one group decision?
Social Influence Defined

Social influence is the process by which group
members influence one another’s opinions.
 Researchers posit that the process of social
influence is part of the overall process that a
group uses to “formulate” a decision based on the
members’ opinions.
 Choice dilemmas involve two options:
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Attractive Outcome – only some probability of success
(“risky” choice).
Less Attractive Outcome – will definitely succeed
(safe or “cautious” choice).
Group Polarization
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Prediscussional Opinions impact on Possible
Outcomes (Decisions)
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All members have the same opinion.
Some group members tend toward risk and some
tend toward caution.
All group members are on one side, either risk or
caution.
Risky Shift – eventual decision is riskier than the
mathematical average would predict.
 Cautious Shift – when groups make more
cautious decisions than individuals.

Risky Shifts Explained

Diffusion of Responsibility
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Familiarization
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Anxiety about possible consequences of a risky decision
decreases as people become familiar with choice dilemma.
Leadership Theories

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Don’t worry about possible negative consequences because
group can diffuse responsibility for the decision.
Focus is on how specific members influence groups (power,
conformity, deviance)
Value Theory

Individuals take more chances in the presence of others than
they would take alone.
Group Polarization

Are group decisions usually more extreme than
the individual members’ prediscussion
judgments?
 The study of group polarization can lead to a
general theory of social influence in groups.
 Choice dilemmas help scholars examine and
theorize about group polarization, and group
polarization helps them look at social influence.
General Social Influence Theories
 No
Social Influence (social decision
schemes)
 Opinion Expression (social comparison)
 New Information (persuasive arguments)
 Opinion Expression and New Information
 Structurational Theory (group discussion)
#1 - Group Decisions
WITHOUT Social Influence

Social influence is NOT important in group decision
making.
 Groups come to their decisions by combining
prediscussional opinions.
 Conclusions are based solely on an arithmetic average.
 SOCIAL DECISION SCHEMES – rules that groups use
to combine individual members’ decisions into a group
decision
 “Majority Model”
 NOT a good explanation of the process by which groups
make decisions!
#2 - Social Influence
from Opinion Expression

Social influence happens when group members listen to one another
express opinions about the available options.

Social influence occurs because people want to agree with the
majority.
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Learning about other people’s opinions is enough to bring about social
influence.

Deliberation is important.

Social comparison approach – valence of risk

Viable – but INCOMPLETE (does not explain WHY the group
polarization effect occurs.
#3 – Social Influence
From New Information

Social influence is important in the decision-making
process.
 Group members talk about their opinions during
meetings and establish advantages and disadvantages
of each option.
 Group uses the members’ new opinions to help it decide
on the best option.
 Group members REQUIRE new information before
social influence can occur.
 Persuasive Arguments Approach
 “Hidden Profile Effect” – risky arguments remain hidden.
#4 – Social Influence from Opinion
Expression AND New Information
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Combined Social Comparison / Persuasive Arguments
BOTH opinion expression and new information can affect the opinions
of group members.
Social influence is a result of two aspects of group interaction:
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Social comparison process that leads to biased group discussion.
New (but often biased) information that group members learn from one
another when they discuss the options.
What members think BEFORE group discussion is important—early
opinions and arguments predict a group’s decision.
Input-Process-Output Model of Group Discussion
Social comparison theory combines with persuasive arguments theory
to account for group polarization.
Good SUPPORTING EVIDENCE to Support Proposal
Ability to explain social influence in general.
#5 – Social Influence from
GROUP DISCUSSION
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Group discussion itself has a larger role in the influence
process
Structurational Theory
When people come into groups they already have
opinions about what they like best.
What HAPPENS during group discussion is of utmost
importance.
Members’ initial opinions may relate only slightly to their
final opinions.
FOCUS on CONTENT of group discussion (not on
prediscussional opinions) to predict outcomes
Cannot explain why participants bring up new arguments
any better than persuasive arguments theory.
Should group discussion be given such a large role in the
social influence process?
The Valence Model
 All
proposals in groups have levels of
acceptability, which group discussion both
governs and reflects.
 Positive and Negative Evaluations of Ideas
 “Thresholds of Acceptability”
Social Influence Conclusions
 No
single theory about group polarization
is absolutely successful.
 Valid theories regarding group decision
making must account for two (2)
propositions:
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Individual opinions are most important ; group
decisions are primarily a result of the opinions
of group members.
Individual opinions CHANGE as a result of
group discussion (social learning).
Summary

Group Polarization



General Social Influence Theories






No Social Influence (social decision schemes)
Opinion Expression (social comparison)
New Information (persuasive arguments)
Opinion Expression and New Information
Structurational Theory (group discussion)
The Valence Model



Risky Shift
Cautious Shift
Universal Social Influence Theory
Threshold Levels
General Propositions & Conclusions
Coming Soon…
 GROUP
DECISION MAKING

The study of GROUP PROCESS

GROUP STRUCTURE