Course: Social Psychology, NYU | Source: Final Exam Word List Difficulty: Intermediate | Prerequisites: Persuasion, Group Influence, Prejudice, and Aggression notes
Tags: altruism, helping behaviour, kin selection, reciprocity, social exchange, tit-for-tat, dictator game, ultimatum game, altruistic punishment, parochial altruism, empathy, egoistic helping, bystander effect, pluralistic ignorance, diffusion of responsibility, prisoner's dilemma, public goods, tragedy of the commons, mirror-image perceptions, contact hypothesis, Allport, superordinate goals, integrative agreement, peacemaking, 4 C's
These two units bookend the course's exploration of how people treat one another. Altruism and helping ask why people sometimes sacrifice their own interests for strangers, and why they sometimes walk past someone in distress. Conflict and peacemaking ask why groups fall into destructive competition and what it takes to pull them back. Together, these topics tie together threads from every earlier unit: persuasion (how leaders mobilise cooperation), group influence (diffusion of responsibility), prejudice (intergroup hostility), aggression (the cost of unresolved conflict), and attraction (empathy, reciprocity, trust).
Altruism is explained by evolutionary accounts (kin selection, reciprocity), social-exchange logic, and empathy. Helping is blocked by the bystander effect, which arises from diffusion of responsibility and pluralistic ignorance. Conflict is modelled by social dilemmas (prisoner's dilemma, tragedy of the commons). Peacemaking requires contact under the right conditions, cooperation toward shared goals, open communication, and reciprocal conciliation.
Altruism
Behaviour intended to benefit another person without expectation of personal gain. Whether truly selfless motivation exists is one of social psychology's central debates.
Kin selection
An evolutionary explanation for altruism: genes that promote helping close relatives survive because those relatives share your genes. Helping kin indirectly promotes your own genetic fitness.
Reciprocity (reciprocal altruism)
Helping others with the expectation that the favour will be returned. Over evolutionary time, organisms that cooperated with partners who reciprocated outperformed pure selfishness.
Social-exchange theory
All human relationships involve a cost-benefit analysis. People help when the perceived benefits (gratitude, reduced guilt, social approval) outweigh the costs (time, danger, effort). Under this view, even apparent altruism serves self-interest.
Think of it as: people help because it pays, one way or another.
Criticism of evolutionary explanations
Evolutionary accounts (kin selection, reciprocity) struggle to explain helping behaviour toward strangers or enemies, anonymous donations, and self-sacrifice with no possibility of return. Critics argue these accounts are unfalsifiable and reduce complex human motives to gene-level logic.
Tit-for-tat rule
A strategy in repeated interactions: cooperate on the first move, then mirror whatever the other person did on the previous move. Tit-for-tat is simple, forgiving, and retaliatory, and it tends to outperform other strategies in computer simulations of cooperation.
The dictator game (Kahneman et al., 1986)
One player (the dictator) is given money and can share any amount (including nothing) with a second player, who must accept whatever is offered. Purely self-interested actors would keep everything, but most dictators share something, suggesting a genuine concern for fairness.
Altruistic punishment
Punishing norm violators at a personal cost, even when there is no direct benefit to the punisher. In economic games, people will pay to punish unfair players, which enforces cooperation norms.
Ultimatum game
One player proposes how to split a sum of money; the other can accept or reject. Rejection means neither player gets anything. Offers perceived as unfair (typically below about 30%) are frequently rejected, even though rejection is economically irrational.
Think of it as: people will sacrifice money to punish unfairness.
Parochial altruism
Altruism directed preferentially toward members of one's own group, sometimes combined with hostility toward out-groups. Helping the in-group and harming the out-group can be two sides of the same coin.
Empathy
The ability to understand and share the feelings of another person. Empathy is the key mechanism proposed by the empathy-altruism hypothesis.
Egoistic vs. altruistic helping
The empathy-altruism hypothesis (Batson) argues that empathic concern for another produces genuinely altruistic motivation. The egoistic alternative says that even empathy-driven helping ultimately aims to reduce the helper's own distress. The debate remains unresolved.
Decision-tree model of bystander intervention
Latane and Darley proposed that bystanders must pass through several steps before helping: notice the event, interpret it as an emergency, assume personal responsibility, know how to help, and decide to act. Failure at any step stops helping.
Pluralistic ignorance
A situation in which everyone privately feels concerned but assumes, based on others' calm appearance, that there is no emergency. Each person's inaction reinforces everyone else's inaction.
Think of it as: "nobody else looks worried, so it must not be serious."
Bystander effect
The tendency for individuals to be less likely to help when other bystanders are present. The more bystanders, the less likely any one person is to intervene. Driven by diffusion of responsibility and pluralistic ignorance.
Evolutionary accounts (kin selection, reciprocal altruism) explain helping as a gene-level strategy. You help relatives because you share genes; you help non-relatives because they might return the favour. These accounts predict that helping decreases with genetic distance and when reciprocation is impossible.
Social-exchange theory frames helping as a cost-benefit transaction. Helping produces rewards (feeling good, social approval, reduced guilt); not helping produces costs (guilt, social disapproval). Under this view, purely selfless altruism is an illusion.
The empathy-altruism hypothesis (Batson) pushes back: when we feel genuine empathic concern, we help even when escape from the situation is easy, suggesting that the motivation is other-focused, not self-focused.
The debate between egoistic and altruistic accounts is unresolved. For exam purposes, know both positions and the evidence each side cites.
The dictator game shows that people share even when they have no strategic reason to. This undermines pure self-interest models.
The ultimatum game shows that people reject unfair offers at personal cost, enforcing a fairness norm.
Altruistic punishment extends this: people punish free-riders even when punishment costs them, which helps maintain cooperation in groups.
Tit-for-tat is the optimal strategy in repeated interactions: start cooperative, then mirror. It succeeds because it is clear (others can predict your behaviour), retaliatory (cheaters are punished immediately), and forgiving (a single cooperation restores the relationship).
Parochial altruism complicates the picture: altruism toward the in-group and hostility toward the out-group often co-occur. This ties back to the prejudice unit and the minimal group paradigm.
Inspired by the Kitty Genovese case (1964). Latane and Darley developed the decision-tree model to explain why bystanders so often fail to act.
The five steps: notice the event, interpret it as an emergency, take personal responsibility, know how to help, decide to act.
Pluralistic ignorance blocks step 2: in ambiguous situations, people look to others for cues. If everyone is looking at everyone else and nobody is reacting, each person concludes there is no emergency.
Diffusion of responsibility blocks step 3: the more bystanders present, the less any individual feels personally responsible.
Reducing the bystander effect: single out a specific person ("you in the red jacket, call 999"), which restores personal responsibility.
Real-world application: first-aid and CPR training explicitly teaches people to overcome the bystander effect by assigning tasks to specific individuals.
Prisoner's dilemma
A two-person game in which mutual cooperation produces the best joint outcome, but each individual is tempted to defect because defection yields a higher personal payoff regardless of what the other does. If both defect, both lose. Models the tension between individual self-interest and collective welfare.
The public goods game
A multi-person version of the prisoner's dilemma. Players choose how much to contribute to a shared pool, which is then multiplied and divided equally. Each player is tempted to free-ride (contribute nothing, benefit from others' contributions).
Tragedy of the commons
When a shared resource (common pasture, fishery, atmosphere) is open to all, each individual is incentivised to take as much as possible before others do, leading to the resource's depletion. The rational individual choice is collectively irrational.
Think of it as: everyone's incentive to overuse a shared resource destroys the resource for everyone.
Mirror-image perceptions
In conflict, each side holds a mirror image of the other: "we are peaceful and they are hostile," while the other side believes exactly the same in reverse. This mutual distortion fuels escalation because both sides see their own actions as defensive and the other's as aggressive.
Peacemaking: the 4 C's
Four research-backed strategies for reducing intergroup conflict: contact, cooperation, communication, and conciliation.
Gordon Allport's contact hypothesis
Intergroup contact reduces prejudice, but only under specific conditions: equal status between groups, common goals, intergroup cooperation, and support from authorities or social norms.
Think of it as: contact works, but only the right kind of contact.
Superordinate goals
Goals that can be achieved only through cooperation between groups that are otherwise in conflict. The mechanism demonstrated in Sherif's Robbers Cave study: the boys who had been hostile rivals became cooperative when they needed both groups to fix a water supply problem.
Integrative agreement
A negotiation outcome in which both parties find a solution that satisfies the core interests of each side, rather than simply splitting the difference (compromise). Integrative agreements require understanding the other side's real needs, not just their stated positions.
The prisoner's dilemma, the public goods game, and the tragedy of the commons are all social dilemmas: situations where individual rationality leads to collective irrationality.
In the prisoner's dilemma, the dominant strategy for each player is to defect, yet mutual cooperation would leave both better off. This captures the core tension in arms races, trade disputes, and environmental agreements.
The public goods game scales this to groups. Free-riding increases as group size increases (parallels social loafing from the Group Influence unit).
The tragedy of the commons applies to shared natural resources. Without regulation or norms, overuse is inevitable. Real-world application: overfishing, carbon emissions, and groundwater depletion are all tragedies of the commons.
Each side in a conflict perceives itself as reasonable and the other as hostile. These mirror images are self-reinforcing: defensive actions by one side are perceived as aggressive by the other, prompting a "defensive" response that is perceived as aggressive in return.
Breaking mirror-image perceptions requires perspective-taking, third-party mediation, or a dramatic unilateral concession (GRIT: Graduated and Reciprocated Initiatives in Tension-Reduction).
Contact: Allport's contact hypothesis states that intergroup contact reduces prejudice when four conditions are met: equal status, common goals, cooperation, and institutional support. Without these conditions, contact can worsen prejudice.
Cooperation: Superordinate goals are the mechanism. When groups must work together to achieve something neither can achieve alone, hostility decreases. The Robbers Cave study is the classic demonstration.
Communication: Direct negotiation, mediation, and arbitration help groups understand each other's real interests. Integrative agreements emerge when negotiators move beyond stated positions to underlying needs.
Conciliation: GRIT strategy, small unilateral concessions that signal good faith and invite reciprocation. Each step is small enough that the risk of exploitation is limited, but large enough to signal genuine intent.
Real-world application: post-conflict reconciliation programmes (truth commissions, desegregation under judicial oversight, joint economic development projects) all draw on some combination of these four C's.
Students often think the bystander effect means people do not care. The research shows they do care but are inhibited by social dynamics (pluralistic ignorance, diffusion of responsibility).
Students confuse the dictator game with the ultimatum game. In the dictator game, the second player has no power (must accept). In the ultimatum game, the second player can reject and destroy both shares.
Students assume the contact hypothesis says any contact reduces prejudice. It does not. Contact must meet Allport's four conditions; unstructured contact between unequal groups can increase prejudice.
Students sometimes treat altruism and egoism as proven conclusions. The empathy-altruism debate is ongoing; the exam expects you to present both sides.
⚠️ Know the five steps of Latane and Darley's decision-tree model and be able to identify where the process breaks down in a given scenario.
⚠️ Be able to distinguish the dictator game, ultimatum game, and prisoner's dilemma by their rules and what each demonstrates.
⚠️ Allport's contact hypothesis conditions (equal status, common goals, cooperation, institutional support) are highly testable. Memorise all four.
⚠️ Understand the tragedy of the commons well enough to apply it to a novel example (not just the original grazing metaphor).
⚠️ Know the empathy-altruism hypothesis vs. the egoistic alternative, and the evidence Batson cites (easy-escape experiments).
True or False: In the dictator game, the second player can reject the offer.
Fill in the blank: The bystander effect is driven by two key mechanisms: __________ and diffusion of responsibility.
True or False: The contact hypothesis predicts that any form of intergroup contact will reduce prejudice.
Fill in the blank: The __________ of the commons occurs when individuals deplete a shared resource by acting in their own self-interest.
True or False: Tit-for-tat is a strategy that always defects.
Answers: 1. False (only in the ultimatum game can the second player reject). 2. Pluralistic ignorance. 3. False (contact must meet specific conditions). 4. Tragedy. 5. False (tit-for-tat starts cooperatively, then mirrors the other player's last move).
Q: A woman collapses on a busy city pavement. Dozens of pedestrians walk past without stopping. Using Latane and Darley's model, explain why helping did not occur and identify the most likely points of failure.
A: The decision-tree model predicts that helping fails when any step is not completed. In a busy street, pluralistic ignorance is the likely culprit at step 2 (interpreting the event as an emergency): each pedestrian sees others walking past calmly and concludes the situation is not serious. Diffusion of responsibility blocks step 3: with dozens of potential helpers, no one feels personally responsible.
Q: Two nations in a territorial dispute each view themselves as peace-loving and the other as aggressive. Name this phenomenon and explain how it perpetuates conflict.
A: Mirror-image perceptions. Each side's "defensive" actions appear aggressive to the other, which responds with its own "defensive" escalation. The cycle continues because each side has evidence (the other's actions) confirming its belief that the other is the aggressor.
Q: A city council wants to reduce racial prejudice by building a shared community centre in a diverse neighbourhood. Based on the contact hypothesis, what conditions must the council ensure for this strategy to work?
A: Allport's contact hypothesis requires four conditions: equal status between groups within the centre, common goals for the activities, intergroup cooperation (not just proximity), and support from authorities or norms (the council actively endorsing and modelling integration). Without these, the centre could simply become a space where groups coexist without meaningful interaction, or where existing tensions play out.
Q: In a public goods game, contributions decline over repeated rounds. Explain why, and suggest one mechanism that could sustain cooperation.
A: Contributions decline because players observe free-riders who benefit without contributing, and cooperators reduce their own contributions to avoid being exploited. Altruistic punishment (allowing players to pay a cost to penalise free-riders) sustains cooperation by making free-riding costly. Other mechanisms include communication (allowing players to discuss strategy) and reputation tracking.
The bystander effect connects back to Group Influence (diffusion of responsibility mirrors social loafing; pluralistic ignorance relates to conformity). The prisoner's dilemma and tragedy of the commons connect to Prejudice through realistic group conflict theory: competition for scarce resources fuels intergroup hostility. Superordinate goals tie together the Prejudice unit (Sherif's Robbers Cave) and this unit's peacemaking framework. The empathy-altruism debate links to Attraction & Intimacy: empathy and self-disclosure are the emotional building blocks of both helping and close relationships.
Altruism, helping behaviour, prosocial behaviour, kin selection, Hamilton's rule, reciprocal altruism, Trivers, social exchange, cost-benefit, Batson, empathy-altruism hypothesis, egoistic helping, tit-for-tat, Axelrod, dictator game, Kahneman, ultimatum game, altruistic punishment, third-party punishment, parochial altruism, in-group favouritism, Latane, Darley, bystander effect, Kitty Genovese, diffusion of responsibility, pluralistic ignorance, five-step model, prisoner's dilemma, Nash equilibrium, public goods game, free-rider problem, tragedy of the commons, Hardin, mirror-image perceptions, GRIT, Osgood, contact hypothesis, Allport, equal status, superordinate goals, integrative agreement, win-win, mediation, conciliation, 4 C's of peacemaking