How individuals think about, influence, and relate to one another. Covers conformity (Asch line experiments, informational vs. normative influence), obedience (Milgram experiments, situational factors), attitudes (formation, change, cognitive dissonance, persuasion), group dynamics (groupthink, social facilitation, social loafing, deindividuation), and prejudice (stereotyping, implicit bias, stereotype threat, intergroup conflict, contact hypothesis). Use when analyzing social influence, group behavior, attitude formation, prejudice, or interpersonal processes.
Social psychology studies how people's thoughts, feelings, and behaviors are influenced by the actual, imagined, or implied presence of others (Allport, 1954). It sits at the intersection of psychology and sociology, sharing sociology's interest in group processes but keeping the individual as the unit of analysis. The field's most powerful findings demonstrate that situations shape behavior far more than most people intuit -- a lesson learned repeatedly through landmark experiments on conformity, obedience, and helping behavior.
Agent affinity: hooks (intersectionality, social justice, power dynamics), vygotsky (social-cultural context), kahneman (social judgment biases)
Concept IDs: psych-social-influence, psych-prejudice-stereotyping, psych-prosocial-behavior, psych-attribution-theory
| # | Domain | Core Question | Landmark Study |
|---|---|---|---|
| 1 | Conformity | When and why do people align with group norms? | Asch (1951) line experiments |
| 2 | Obedience | Why do people follow destructive orders? |
| Milgram (1963) shock experiments |
| 3 | Attitudes | How are attitudes formed, maintained, and changed? | Festinger (1957) cognitive dissonance |
| 4 | Group dynamics | How does being in a group change individual behavior? | Janis (1972) groupthink |
| 5 | Prejudice | What causes prejudice and how can it be reduced? | Sherif (1954) Robbers Cave; Allport (1954) contact hypothesis |
Solomon Asch (1951) showed participants a standard line and three comparison lines. In a group of confederates who unanimously gave the wrong answer, approximately 75% of participants conformed at least once across 12 trials. On any given trial, the conformity rate was about 37%. Participants were not uncertain -- the correct answer was obvious. They conformed to avoid social rejection.
| Factor | Effect on conformity |
|---|---|
| Group size | Increases up to ~3-4, then plateaus |
| Unanimity | One dissenter reduces conformity dramatically (~25% drop) |
| Task difficulty | Ambiguity increases conformity |
| Cultural context | Collectivist cultures show higher conformity rates (Bond & Smith, 1996) |
| Public vs. private | Conformity drops sharply when responses are anonymous |
| Status of group members | Higher-status members produce more conformity |
Moscovici (1969) demonstrated that a consistent minority can shift the majority's private beliefs over time. The key factor is consistency -- a minority that wavers has no influence. Minority influence operates through informational processes (people think harder about consistent minority positions) and tends to produce private attitude change rather than public compliance.
Stanley Milgram (1963) found that 65% of participants administered the maximum 450-volt shock to a screaming, eventually silent confederate, when instructed by an experimenter in a lab coat. This was not sadism -- participants showed extreme distress (sweating, trembling, nervous laughter). They obeyed because the situation was structured to elicit obedience.
Milgram ran systematic variations that reveal the power of situational factors:
| Variation | Obedience rate | Why |
|---|---|---|
| Baseline (experimenter in room) | 65% | Full authority presence |
| Experimenter gives orders by phone | 21% | Reduced authority salience |
| Learner in same room | 40% | Increased victim salience |
| Participant must force learner's hand onto shock plate | 30% | Physical proximity to suffering |
| Two experimenters disagree | 0% | Conflicting authority releases the participant |
| Ordinary person (no lab coat) gives orders | 20% | Authority stripped of legitimacy |
| Participant sees others disobey | 10% | Social proof of disobedience |
Milgram proposed that participants entered an "agentic state" -- shifting from autonomous moral agents to agents of authority, deferring moral responsibility to the experimenter. This mechanism explains obedience in bureaucratic systems: each person follows orders, no one takes responsibility.
Milgram's experiments would not pass modern IRB review. They caused genuine psychological distress. But they revealed something important: ordinary people can perform harmful acts under situational pressure. The findings remain relevant to understanding Abu Ghraib, corporate fraud, and everyday complicity.
Attitudes have three components (the ABC model):
Festinger (1957) proposed that holding two contradictory cognitions creates psychological discomfort (dissonance) that motivates change. The classic experiment (Festinger & Carlsmith, 1959): participants who were paid $1 to lie about a boring task rated it as more enjoyable than those paid $20. The $1 group had insufficient external justification, so they reduced dissonance by changing their attitude ("maybe it wasn't so boring").
Dissonance drives post-decision rationalization (spreading of alternatives), effort justification (hazing increases group loyalty), and selective exposure to confirming information.
The Elaboration Likelihood Model (Petty & Cacioppo, 1986) distinguishes two routes:
Cialdini (2001) identified six principles of influence: reciprocity, commitment/consistency, social proof, authority, liking, and scarcity. Each exploits automatic psychological tendencies.
Attitudes predict behavior imperfectly. LaPiere (1934) traveled with a Chinese couple to 251 establishments and was refused service once, but 92% of the same establishments later said they would not serve Chinese patrons. Ajzen's (1991) Theory of Planned Behavior improved prediction by adding subjective norms (what others think I should do) and perceived behavioral control (whether I believe I can do it).
Zajonc (1965) resolved decades of contradictory findings: the presence of others improves performance on simple/well-learned tasks (facilitation) but impairs performance on complex/novel tasks (inhibition). The mechanism is arousal -- others increase physiological arousal, which enhances dominant responses. If your dominant response is correct (simple task), you perform better; if it is incorrect (complex task), you perform worse.
Latane, Williams, and Harkins (1979) showed that people exert less effort when working collectively than individually. The effect is reduced by making individual contributions identifiable, increasing task importance, and working with valued group members. Collectivist cultures show less social loafing than individualist cultures (Karau & Williams, 1993).
Janis (1972) analyzed foreign policy disasters (Bay of Pigs, Pearl Harbor) and identified groupthink -- a mode of thinking in highly cohesive groups where the desire for unanimity overrides realistic appraisal. Symptoms include illusion of invulnerability, collective rationalization, stereotyping of out-groups, self-censorship, and illusion of unanimity. Prevention: assign a devil's advocate, encourage dissent, invite outside experts, use anonymous polling.
Zimbardo (1969) proposed that anonymity, diffused responsibility, and arousal cause deindividuation -- the loss of self-awareness and individual accountability. The Stanford Prison Experiment (1971), despite methodological criticisms (Haslam & Reicher, 2012), demonstrated how assigned roles in institutional contexts can produce abusive behavior. Modern research emphasizes that deindividuation increases sensitivity to situational norms (SIDE model) rather than simply releasing aggression.
Social identity theory (Tajfel & Turner, 1979): people derive self-esteem from group membership and enhance it by favoring the in-group over out-groups. The minimal group paradigm shows that even arbitrary group assignments (overestimators vs. underestimators) produce in-group favoritism.
Realistic conflict theory (Sherif, 1954): competition for scarce resources produces intergroup hostility. Sherif's Robbers Cave experiment showed that competitive games between two groups of boys produced intense hostility, reduced only when superordinate goals (requiring cooperation) were introduced.
Implicit bias (Greenwald et al., 1998): the Implicit Association Test (IAT) measures automatic associations between social categories and evaluative attributes. Most people show implicit preferences for dominant groups even when they explicitly reject prejudice. The relationship between implicit bias and discriminatory behavior is debated (Oswald et al., 2013) but the existence of the associations is well-established.
Steele and Aronson (1995) showed that making race salient before a test reduced Black students' performance, while the same test without racial salience produced no performance gap. The mechanism is anxiety and cognitive load: awareness that one's group is stereotyped as inferior consumes working memory resources. Stereotype threat has been demonstrated across many groups and domains (women in math, older adults in memory tasks, white men in athletics).
Contact hypothesis (Allport, 1954): intergroup contact reduces prejudice under four conditions: equal status, common goals, cooperation, and institutional support. Pettigrew and Tropp's (2006) meta-analysis of 515 studies confirmed that contact reliably reduces prejudice, even when Allport's conditions are not fully met, though the conditions strengthen the effect.
Perspective-taking -- imagining another person's experience increases empathy and reduces automatic bias (Galinsky & Moskowitz, 2000).
Intergroup dialogue -- structured conversations across group boundaries that address power, privilege, and difference. Most effective when facilitated, sustained, and embedded in institutional change.