Difficulty: Introductory to Intermediate | Prerequisites: Basic familiarity with social psychology concepts (conformity, social influence). If you have not covered those yet, start there.
This topic covers how groups shape individual behaviour, from the boost (or drag) of having others around to the way group discussion can push opinions to extremes. It sits at the heart of social psychology because nearly every other topic in the course (prejudice, aggression, conflict) plays out differently once people are in groups rather than acting alone. You should already have a rough sense of what conformity and social norms are. If terms like "normative influence" and "informational influence" ring a bell, you are in good shape.
Groups can improve or worsen individual performance depending on whether people feel evaluated and whether the task is simple or complex. When accountability drops, effort drops (social loafing) and inhibitions can vanish (deindividuation). Group discussion tends to amplify whatever direction members already lean, sometimes all the way to groupthink, but a consistent minority voice can push back.
Group
Two or more people who, for longer than a few moments, interact with and influence one another and perceive one another as "us." In simple terms, it is any set of people who see themselves as a unit and act on that.
Social facilitation
The tendency for people to perform simple or well-learned tasks better, and complex or novel tasks worse, when others are present. Think of it as an audience effect: easy things get easier, hard things get harder.
Dominant response
The reaction a person is most likely to give on a task. Arousal from others' presence strengthens whatever that default response is, for better or worse.
Evaluation apprehension
Concern about how others are judging our performance. In simple terms, it is the nervousness you feel when you know someone is watching and scoring you.
Social loafing
The tendency for people to exert less effort when pooling their work toward a common goal than when individually accountable. Think of it as coasting in a group project because no one can tell exactly how much you contributed.
Free rider
A person who benefits from the group's effort but contributes little or nothing in return.
Deindividuation
Loss of self-awareness and evaluation apprehension that occurs in group situations fostering anonymity. In simple terms, it is the feeling of "disappearing into the crowd" where normal restraints loosen.
Self-awareness
A self-conscious state in which attention focuses on oneself, making a person more sensitive to their own attitudes and dispositions. It is the psychological opposite of deindividuation.
Group polarization
The tendency for group members to hold opinions or make decisions that are more extreme than their initial individual positions after discussing the topic together. Think of it as the group amplifying whatever direction people were already leaning.
Groupthink
A phenomenon where people in a cohesive group prioritise harmony and consensus over critical thinking, leading to poor decision-making.
Minority slowness effect
The tendency for people holding minority views to express those views more slowly than people in the majority.
Pluralistic ignorance
A situation in which group members each privately disagree with the apparent group norm but assume everyone else accepts it. In simple terms, everyone goes along because they mistakenly believe everyone else agrees.
Triplett (1898) noticed that cyclists rode faster alongside others than alone, which kicked off research into social facilitation. The original meaning was straightforward: other people boost performance. Later work showed this only holds for simple or well-practised tasks.
Zajonc's drive theory: The presence of others creates arousal, and arousal strengthens the dominant response.
On easy tasks the dominant response is the correct one, so performance improves.
On difficult tasks the dominant response is often an error, so performance suffers.
Three explanations compete for why the presence of others produces arousal:
Evaluation apprehension: We worry about being judged. Evidence: when observers are blindfolded, the facilitation effect disappears.
Distraction: Splitting attention between the audience and the task overloads our cognitive system, generating arousal.
Mere presence: Zajonc argued that the sheer physical presence of another organism is enough. Social facilitation occurs even in nonhuman animals (cockroaches run mazes faster with an audience), which suggests an innate arousal response that operates without any evaluation or distraction.
When people pool their efforts toward a common goal and are not held personally accountable, collective effort often falls below the sum of individual efforts.
Key contrast with social facilitation: Social facilitation kicks in when individual efforts can be evaluated. Social loafing kicks in when they cannot.
Evaluation possible, individual goal = increased apprehension, better performance on easy tasks.
Evaluation impossible, group goal = decreased apprehension, reduced effort.
Free riders benefit from the group while giving little back, which can drag everyone's motivation down.
Social loafing in everyday life:
Employees produce more when their individual contributions are tracked.
The effect appears across cultures, though collectivist cultures sometimes show it less.
People loaf less when the task is challenging, personally meaningful, or involves a group they care about.
Loafing appears in donations of money and time as well as physical effort.
When arousal and diffused responsibility combine, normal inhibitions weaken and people lose their sense of individual identity.
Deindividuation is the loss of self-awareness and evaluation apprehension that occurs in group situations fostering responsiveness to group norms, whether those norms are positive or negative.
Factors that promote deindividuation:
Group size: Larger groups make it easier to lose self-awareness. Attention shifts from "What do I think?" to "What is everyone doing?" People attribute their behaviour to the situation ("everyone's doing it") rather than to personal choice.
Anonymity: Reduces self-consciousness and increases responsiveness to situational cues. In a classic study, children in groups who were anonymous took extra Halloween sweets more often than identified children.
Diminished self-awareness: Group experiences that pull attention away from the self tend to disconnect behaviour from personal attitudes. Self-awareness is the psychological opposite of deindividuation; the two are inversely related.
Real-world application: Deindividuation helps explain why crowds can do things their individual members would never do alone, from riots to flash mobs. The same mechanism can also amplify positive behaviour if the group norm is prosocial.
After group discussion, members tend to shift toward a more extreme version of whatever position the group already leaned toward. If most members mildly favour a risky option before discussion, they will favour it more strongly afterwards.
Two mechanisms drive group polarization:
Normative influence (social comparison): People want to be seen as good group members. They notice the group's average position and shift beyond it to appear favourably. Pluralistic ignorance plays a role here: people often overestimate how strongly others hold the group position.
Informational influence (persuasive arguments): Discussion exposes members to new arguments that disproportionately favour the side the group already leans toward.
Highly motivated members process these arguments through the central route.
Less motivated members are swayed by the sheer number of arguments heard (peripheral route).
Real-world application: Group polarization is one reason why like-minded communities, from juries to online forums, can drift toward increasingly extreme positions over time.
Groupthink is the phenomenon where a cohesive group prioritises agreement over critical evaluation, leading to flawed decisions.
Conditions that make a group vulnerable:
An amiable, cohesive group
Relative isolation from dissenting viewpoints
A directive leader who signals a preferred outcome
Eight symptoms of groupthink:
Illusion of invulnerability: Excessive optimism blinds the group to warnings of danger.
Unquestioned belief in the group's morality: Members assume they are inherently ethical and ignore moral questions.
Rationalisation: The group collectively justifies its decisions, discounting challenges.
Stereotyped views of opponents: Opposing parties are dismissed as too inferior, unintelligent, or malicious to negotiate with.
Conformity pressure: Members who raise doubts are rebuffed.
Self-censorship: Members withhold their misgivings to avoid uncomfortable disagreement.
Illusion of unanimity: Pressure not to puncture the group "consensus" creates a false appearance of agreement.
Mindguards: Some members actively shield the group from information that could challenge its decisions.
Preventing groupthink:
Leaders should remain impartial rather than stating a preference early.
Encourage critical evaluation and welcome outside critiques.
Hold a "second-chance" meeting before implementing decisions to air lingering doubts.
When groups perform better:
Not every group decision is flawed. Multiple heads are often better than one when brainstorming is structured well:
Combine group and solitary brainstorming sessions.
Have members interact by writing rather than speaking aloud.
Use electronic brainstorming (e.g. shared documents, email) to reduce production blocking.
Majorities are not the only source of influence. A consistent minority can shift the group over time.
What makes a minority persuasive:
Consistency: Holding firm to a position across time and across different members. Consistent non-conformity is socially costly, but that very cost signals conviction.
Self-confidence: A minority that appears confident raises doubts in the majority. Consistency and persistence convey that confidence.
Defection from the majority: A lone defector from the majority tends to be even more persuasive than a consistent minority voice, because the defection carries an implicit message: "I used to agree with you, and I changed my mind."
The minority slowness effect: People with minority views tend to express them more slowly than majority holders. This delay can make the minority appear less numerous than it is, but the views still exert influence over time, particularly through informational channels.
"Social facilitation always helps." It does not. It only helps on easy or well-learned tasks. On difficult tasks the same arousal worsens performance.
"Social loafing means people are lazy." Loafing is situational, not a character trait. The same person who loafs in an anonymous group will work hard when individually accountable or when the task matters to them.
"Deindividuation only produces bad behaviour." Deindividuation amplifies whatever norm the group is responding to. If the group cue is prosocial (e.g. a charity event), deindividuated members may behave more generously.
"Group polarization means the group always becomes more extreme." It means the group shifts further in the direction it was already leaning. If most members were cautious, the group becomes more cautious, not more reckless.
Be able to explain why the same audience can improve performance on one task and hurt it on another (Zajonc's drive theory + dominant response).
Know the distinction between social facilitation and social loafing: the pivot is whether individual effort is identifiable.
Expect a question on the eight symptoms of groupthink. You do not need to memorise all eight word-for-word, but you should be able to list at least five and give a brief example of each.
Understand the two explanations for group polarization (normative vs. informational influence) and be ready to apply them to a scenario.
Minority influence is a favourite short-answer topic: know the three factors (consistency, self-confidence, defection) and the minority slowness effect.
True or false: Social facilitation improves performance on all types of tasks. (False, only simple/well-learned tasks.)
Fill in the blank: The tendency for people to exert less effort when their contributions cannot be individually identified is called ________. (Social loafing.)
True or false: Deindividuation only leads to antisocial behaviour. (False, it amplifies whatever the situational norm is.)
Fill in the blank: Group polarization is driven by two forces: ________ influence and ________ influence. (Normative; informational.)
True or false: A consistent minority is more persuasive than a lone defector from the majority. (False, a lone defector is often more persuasive.)
Q: A student finds that she performs better on simple multiplication problems when her classmates are watching but worse on complex calculus problems under the same conditions. Which concept best explains this pattern, and what is the underlying mechanism?
A: Social facilitation, explained by Zajonc's drive theory. The presence of others increases arousal, which strengthens the dominant response. For simple tasks the dominant response is correct, so performance improves. For complex tasks the dominant response is often an error, so performance suffers.
Q: A group project at work produces lower output than the sum of what each member would have done alone. No single member's contribution is tracked. What phenomenon is this, and what two changes would reduce it?
A: Social loafing. Two effective changes: (1) make individual contributions identifiable so that each person feels accountable, and (2) make the task more personally meaningful or challenging so members are intrinsically motivated.
Q: Explain how group polarization can occur through normative influence. Use the concept of pluralistic ignorance in your answer.
A: Through normative influence, group members compare their position to what they perceive as the group average and shift beyond it to appear as strong group members. Pluralistic ignorance compounds this: each member overestimates how strongly others support the dominant position, so they push themselves further than necessary. The result is a collective shift toward a more extreme version of the original average.
Q: Name three symptoms of groupthink and explain one strategy for preventing it.
A: Three symptoms include the illusion of invulnerability (excessive optimism), self-censorship (withholding doubts), and conformity pressure (rebuffing dissenters). One prevention strategy is for the leader to remain impartial and not state a preferred outcome early, which frees members to voice genuine objections.
Q: What three factors make a minority voice more likely to influence the majority?
A: Consistency (holding firm over time), self-confidence (projecting conviction), and defection (when a former majority member joins the minority position, this is particularly persuasive because it implies a genuine change of mind).
This material connects directly to prejudice: many of the biases covered later (ingroup favouritism, outgroup stereotyping) are amplified by the same group dynamics discussed here, particularly groupthink and group polarization. It also connects to aggression, where deindividuation and diffused responsibility help explain mob violence and group-amplified hostility. Finally, the conflict and peacemaking unit revisits social dilemmas (prisoner's dilemma, tragedy of the commons), which are group-level versions of the individual accountability problem at the heart of social loafing.
Social facilitation, social inhibition, audience effect, co-action effect, Zajonc, dominant response, drive theory, evaluation apprehension, mere presence, distraction-conflict theory, social loafing, free riding, diffusion of responsibility, collective effort model, deindividuation, anonymity, mob behaviour, crowd psychology, self-awareness, group polarization, risky shift, cautious shift, normative influence, informational influence, persuasive arguments theory, social comparison, pluralistic ignorance, groupthink, Janis, illusion of invulnerability, mindguards, conformity pressure, minority influence, minority slowness effect, consistency, defection, innovation in groups