Social psychology focuses on how we think about, influence, and relate to one another. Social psychologists study the social influences that explain why the same person will act differently in different situations.

We may commit the fundamental attribution error (especially if we come from an individualist Western culture) when explaining others’ behavior, by underestimating the influence of the situation and overestimating the effects of personality.

When we explain our own behavior, however, we more often recognize the influence of the situation.

Attitudes are feelings, often based on our beliefs, that predispose us to respond in certain ways. Attitudes that are stable, specific, and easily recalled can affect our actions when other influences are minimal.

Persuasion can take two forms: peripheral route persuasion and central route persuasion.

Actions also modify our attitudes. This can be seen in the foot-in-the-door phenomenon (complying with a large request after having agreed to a small request) and role playing (acting a social part by following guidelines for expected behavior).

When our attitudes don’t fit with our actions, cognitive dissonance theory suggests that we will reduce tension by changing our attitudes to match our actions.

Solomon Asch and others have found that we are most likely to conform to a group standard when (a) we feel incompetent or insecure, (b) our group has at least three people, (c) everyone else agrees, (d) we admire the group’s status, (e) we have not already committed to another response, (f) we know we are being observed, and (g) our culture encourages respect for social standards.

We may conform to gain approval (normative social influence) or because we are willing to accept others’ opinions as new information (informational social influence).

In Stanley Milgram’s famous experiments, people usually obeyed the experimenter’s orders even when they thought they were harming another person. Obedience was highest when (a) the experimenter was nearby and (b) was a legitimate authority figure supported by an important institution, (c) the victim was not nearby, and (d) there were no role models for defiance.

Strong social influences can make people conform to falsehoods or give in to cruelty.

Even a small minority sometimes sways a group, especially when the minority expresses its views consistently.

Social control (the power of the situation) and personal control (the power of the individual) interact.

In social facilitation, the presence of others arouses us, improving performance on easy tasks. Observers can hinder performance on difficult tasks.

Social loafing is the tendency when participating in a group project to feel less responsible, when we may free ride on others’ efforts.

When the presence of others both arouses us and makes us feel less responsible, we may experience deindividuation—loss of self-awareness and self-restraint.

In group polarization, group discussions with like-minded others cause us to feel more strongly about our shared beliefs and attitudes.

Internet communication magnifies the effect of connecting like-minded people, for better and for worse. People find support, but also often isolation from those with different opinions. Separation plus conversation may thus lead to group polarization.

Groupthink is driven by a desire for harmony within a group, causing its members to overlook important alternatives.

Prejudice is an unfair, usually negative, attitude toward a group and its members. Prejudice’s three components are (a) beliefs (often stereotypes), (b) emotions (negative feelings), and (c) predispositions to action (discrimination).

Open prejudice has decreased, but subtle prejudice and automatic prejudice—occurring without our awareness—continue.

Prejudice involves both explicit and implicit negative attitudes toward people of a particular ethnic group, gender, sexual orientation, or viewpoint.

Social inequalities and social divisions feed prejudice. Favored social groups often justify their higher status with the just-world phenomenon.

We tend to favor our own group (ingroup bias) as we divide ourselves into us (the ingroup) and them (the outgroup).

We may use prejudice to protect our emotional well-being, such as when focusing anger by blaming events on a scapegoat.

The cognitive roots of prejudice grow from our natural ways of processing information: forming categories, remembering vivid cases, and believing that the world is just (and our group’s way of doing things is the right way).

Aggression is a complex behavior resulting from the interaction of biology and experience.

Biology influences our threshold for aggressive behaviors at three levels: genetic (inherited traits), biochemical (such as alcohol or excess testosterone in the bloodstream), and neural (activity in key brain areas).

Frustration (frustration-aggression principle), aversive events, getting rewarded for aggression, seeing an aggressive role model, and poor self-control can all contribute to aggression.

Viewing sexual violence contributes to greater aggression toward women.

Media portrayals of violence provide social scripts that children learn to follow.

Proximity (geographical nearness) increases liking, in part because of the mere exposure effect—exposure to novel stimuli increases liking of those stimuli.

Physical attractiveness increases social opportunities and improves the way we are perceived.

Similarity of attitudes and interests greatly increases liking, especially as relationships develop. We also like those who like us.

Intimate love relationships start with passionate love—an intensely aroused state.

Over time, the strong affection of companionate love may develop, especially if enhanced by an equitable relationship and by intimate self-disclosure.

Altruism is unselfish regard for the well-being of others.

We are most likely to help when we (a) notice an incident, (b) interpret it as an emergency, and (c) assume responsibility for helping. Other factors, including our mood and our similarity to the victim, also affect our willingness to help.

We are least likely to help if other bystanders are present (the bystander effect).

Helping results from socialization, in which we are taught guidelines for expected behaviors in social situations, such as the reciprocity norm and the social-responsibility norm.

Conflicts, perceived incompatibilities of actions, goals, or ideas between individuals and cultures, are often fed by distorted mirror-image perceptions—each party views itself as ethical and peaceful and the other as untrustworthy and evil-intentioned. Perceptions can be self-fulfilling prophecies.

Peace can result when individuals or groups cooperate to achieve superordinate (shared) goals.