Explain how group membership affects cognition and emotion, including group polarisation, groupthink, deindividuation and the bystander effect

What this dot point is asking

QCAA wants you to explain how the presence and influence of a group changes individual cognition (decision-making) and emotion (arousal, responsibility), using named phenomena and studies. You should describe each process, explain why it occurs, and support it with evidence.

The answer

How groups change cognition

Being in a group alters how decisions are made, often making them more extreme or worse.

• Group polarisation. Group discussion tends to strengthen the average pre-existing view, producing a more extreme decision than individuals would make alone. A cautious group becomes more cautious; a risky group becomes riskier.
• Groupthink (Janis, 1972). In highly cohesive groups under pressure, the desire for harmony and agreement overrides realistic appraisal of alternatives. Symptoms include an illusion of invulnerability, self-censorship, pressure on dissenters and an illusion of unanimity. Janis analysed real political fiascos such as the Bay of Pigs invasion. Groupthink can be reduced by encouraging dissent, appointing a devil's advocate and seeking outside opinions.

How groups change emotion and behaviour

Groups also change arousal, accountability and effort.

• Deindividuation. In a crowd or when anonymous, people experience reduced self-awareness and weakened personal accountability, which can release impulsive or antisocial behaviour. Zimbardo's research showed that anonymity (hoods and uniforms) increased participants' willingness to administer shocks, and the Stanford prison study illustrated how anonymity and roles can unleash aggression.
• Social loafing. Individuals tend to exert less effort when working in a group than when working alone, because individual contributions are less identifiable. Ringelmann's rope-pulling work first demonstrated this reduction in effort.

The bystander effect

The bystander effect is the finding that the presence of other people reduces the likelihood that any individual will help in an emergency.

• Darley and Latane (1968). Following the Kitty Genovese case, they staged emergencies and found that the more bystanders present, the less likely and the slower any individual was to help. They explained this through diffusion of responsibility (each person assumes someone else will act) and pluralistic ignorance (people look to others, who also appear calm, and conclude there is no emergency). Their five-step decision model describes the points at which helping can break down: noticing the event, interpreting it as an emergency, taking responsibility, knowing how to help and deciding to act.

Why these processes matter

These phenomena show that individual cognition and emotion are not fixed; they shift systematically with the social context. The same person may make a balanced decision alone but a reckless one in a polarised group, or help readily when alone but freeze in a crowd.

Putting it together for an exam

Identify whether the question concerns cognition (polarisation, groupthink) or emotion and behaviour (deindividuation, loafing, bystander effect), name the process, explain its mechanism, then support it with a named study. Linking the social context to a change in the individual is the key skill.