Source: Textbook Ch. 13–14, Burger 2009
Difficulty: Intermediate | Prerequisites: Ch. 4–12 (cognition, attribution, emotions, attitudes, groups)
Aggression is behaviour intended to cause physical or psychological pain. This chapter explores whether aggression is innate or learned (both), what situational factors trigger it, and how culture, gender, and evolution shape aggressive patterns. It connects to emotions (Ch. 6, particularly anger), attribution (Ch. 5, misperceptions of intent), and group dynamics (Ch. 12, deindividuation).
Aggression is both nature and nurture: genes and childhood abuse interact. Key situational triggers include heat, media violence, social rejection, inequality, and the presence of weapons. The frustration-aggression model identifies anger as the mediating emotion. Dehumanisation lowers the barrier to aggression. Cultures of honour promote reactive aggression after perceived insults. "Venting" or releasing strong emotion does not reduce aggression; cognitive control (distancing, counting to ten) does.
Hostile aggression
Aggression in which causing pain or harm is the sole goal.
Instrumental aggression
Aggression used as a means to achieve another goal (e.g. robbery, intimidation).
Frustration-aggression model
Frustration (a blocked goal) generates aggressive feelings, mediated by anger. The level of aggression depends on the desirability of the goal, the severity of the block, and how close the person was to reaching the goal.
Dehumanisation
Construing others as less than human. Denying human nature (emotions) or human uniqueness (civility, culture). Rationalises aggression and violence.
Culture of honour
A cultural pattern in which people are more likely to respond aggressively to perceived insults to defend reputation (e.g. American South vs North).
Precarious manhood hypothesis
The idea that manhood is perceived as hard-won and easily lost, which motivates men to prove their masculinity through aggression.
Reactive devaluation
Attaching less value to an opposing group's offer in a conflict, unless delivered by a neutral mediator.
Genes and childhood abuse interact. Aggression has both biological and learned components.
Heat: misattribution of physiological arousal can be channelled into aggression
Media violence: increases aggressive acts, desensitises viewers, habituates them to violence, and distorts perceptions of violence prevalence
Video games also produce physiological effects (blood pressure, heart rate)
Copycat violence: more likely when people identify with the perpetrator or the act is perceived as justified
Social rejection: chronic rejection produces aggressive emotions (evolutionary basis: rejection once meant death); ostracism activates the same brain areas as physical pain
Inequality: higher inequality (Gini index) correlates with higher homicide rates
Weapons: the mere presence of a weapon can prime aggressive thoughts and behaviour
Children who are punished tend to be more aggressive (modelling)
Punishment fails to teach what to do instead
Frustration signals a blocked goal, generating aggressive feelings
Not all aggression comes from frustration (e.g. heat) and not all frustration leads to aggression (e.g. learned helplessness)
Anger is the necessary mediating emotion
Denying human nature = no emotions; denying human uniqueness = no civility or culture
Rationalises physical and sexual aggression
Ingroup loyalty can lead to dehumanising outgroups
Counting to ten and distancing work. "Venting" or releasing strong emotion does not reduce aggression.
Culture of honour: defending reputation through reactive aggression (American South vs North)
Rape-prone cultures share characteristics: high violence, frequent warfare, male toughness emphasis, limited women's rights
Stepfamily violence: resources spent on non-genetic kin
Violence against unfaithful spouses: paternity uncertainty (more threatening for men when separated)
Males more likely to commit and to be victims of violent crime
Males more physically aggressive; females more relationally aggressive (rumours, social exclusion)
Evolutionary explanation: male upper-body adaptation for hunting, defence, competing for mates
Cultural explanation: boys expected to be more aggressive; parents discuss emotions more with girls
Precarious manhood hypothesis: both evolutionary and cultural
Less responsive to others' suffering despite being equally perceptive.
Moral exaggerations: see opponents as evil, overestimate extremity of their positions, underestimate common ground
Reactive devaluation: devalue offers from opponents unless mediated
Simplistic reasoning increases in the heat of conflict
Communication and reconciliation: restorative justice reduces desire for revenge
Confidence does not equal accuracy. Cross-race identification is less accurate. The fastest identification tends to be the most accurate. Rehearsal hurts accuracy. Stress reduces accuracy. False confessions occur.
Altruism is helping behaviour with no expected benefit to the self. This chapter examines why people help (empathy, social rewards, evolutionary logic), when they fail to help (bystander effect, diffusion of responsibility), and what situational, cultural, and personality factors influence prosocial behaviour. The Milgram replication (Burger 2009) is included as a research reading on obedience.
Altruism is motivated by empathy (both personal distress and empathetic concern). The biggest barrier to helping is the bystander effect: the presence of others reduces any single person's likelihood of intervening through diffusion of responsibility and pluralistic ignorance. Rural settings produce more helping than urban ones. Evolution explains altruism through kin selection and reciprocity. Cooperation (tit-for-tat) is the optimal long-run strategy.
Altruism
Behaviour motivated by the desire to help another person at a cost to oneself, with no expected benefit.
Empathy
Experiencing the same feelings and emotions as another person, encompassing both distress and concern.
Personal distress
Feeling similarly unpleasant or distressed when witnessing another's suffering. Associated with physiological indicators like heart rate deceleration.
Empathetic concern
Sympathy and compassion for a person in need. Self-reported empathetic concern predicts volunteerism.
Bystander effect
The finding that the presence of others reduces the likelihood that any one individual will intervene in an emergency.
In simple terms, the more people watching, the less likely any one of them is to help.
Diffusion of responsibility
The overall likelihood of help remains roughly the same, but it is spread across more people, so each individual feels less personally responsible.
Pluralistic ignorance (in bystander context)
When no one in a group appears alarmed, each individual assumes no action is required.
Kin selection
Behaviour that benefits the survival of genetic relatives, explained by inclusive fitness.
Reciprocity (in altruism)
Helping non-relatives when the help is likely to be reciprocated in the future.
Tit-for-tat
A cooperation strategy: start by cooperating, then mirror the other person's last move. Encourages cooperation while avoiding exploitation.
Personal distress: feeling similarly unpleasant (physiological: heart rate changes, facial expressions of concern)
Empathetic concern: sympathy and compassion, predicts volunteering
Social rewards: reputation as a "good person"
People who are late or rushing help far less
Bystander effect: more bystanders = less individual likelihood of intervening
Kitty Genovese story (note: the original account was not accurate)
Diffusion of responsibility: total probability of help stays roughly the same, but each person feels less responsible
Pluralistic ignorance: if no one looks alarmed, everyone assumes no help is needed
Bystander factors: cost and ability to help; guilt from not helping boosts mood when you do help
Recipient factors: similarity, attractiveness, and clarity of need increase help
Gender: women more likely to receive help, especially when dressed more femininely
Economics exposure: traditional economics courses reduce helpfulness; money primes a self-sufficient orientation
Rural areas produce more helping than urban areas (urban overstimulation)
This is environmental, not dispositional: city-dwellers help more when placed in rural settings
Rich people have less chronic empathy, but empathy prompts raise prosocial behaviour
Priming religious or civic concepts increases generosity
Being watched (even a picture of eyes) increases altruism
Kin selection: helping genetic relatives increases inclusive fitness
Reciprocity: helping non-relatives when repayment is likely
Prisoner's Dilemma: priming with hostile words or a business context increases competition
Prolonged, repeated interactions promote cooperation
Brain reward regions are more active during cooperation; cooperation is contagious
Economists' assumptions about self-interest become self-fulfilling: professional economists contribute less to charity
Ultimatum Game: high-interdependence cultures allocate more equally
Tit-for-tat: the optimal strategy for encouraging cooperation without being exploited
Obedience to authority is explained by four features:
Obedience to legitimate authority
Gradual increase in demands (foot-in-the-door)
Limited sources of information in a novel situation
Responsibility not assigned or diffused
Findings: no gender difference in obedience; one dissenting person is not enough to establish a counter-norm. The study underscores the power of situational factors over individual disposition.
Students think "venting" anger reduces aggression. Research shows the opposite: releasing strong emotion does not reduce it. Cognitive control (distancing, reappraisal) is more effective.
Students assume the bystander effect means people do not care. The overall probability of someone helping may stay similar; it is the individual's sense of personal responsibility that decreases.
Students believe altruism must be purely selfless. Evolutionary explanations (kin selection, reciprocity) and social rewards (reputation) can motivate helping without negating its prosocial value.
Students think obedience in the Milgram paradigm reflects individual cruelty. Burger's replication underscores that the situation (authority, gradual escalation, diffused responsibility) drives obedience, not the person's character.
⚠️ Know the difference between hostile and instrumental aggression with examples.
⚠️ The frustration-aggression model and its limitations (not all frustration leads to aggression; anger is the mediator) are commonly tested.
⚠️ Be able to explain the bystander effect, diffusion of responsibility, and pluralistic ignorance, and give the Kitty Genovese context.
⚠️ Know the four features of obedience from the Milgram/Burger reading.
⚠️ Tit-for-tat as the optimal cooperation strategy is a frequent exam item.
⚠️ Understand dehumanisation and its link to aggression.
Aggression aimed at causing harm as a means to another goal is called __________ aggression. (instrumental)
True or False: Venting anger effectively reduces aggressive feelings. (False)
The finding that more bystanders leads to less individual helping is the __________. (bystander effect)
True or False: In the Milgram paradigm, women were significantly less obedient than men. (False, no gender difference)
The optimal strategy in iterated Prisoner's Dilemma is __________. (tit-for-tat)
Q: A person is stuck in traffic on a hot day and honks aggressively at the car in front. Using the frustration-aggression model, explain why this happens, and identify one limitation of the model.
A: The blocked goal (getting somewhere on time) creates frustration, which generates aggressive feelings mediated by anger. The heat contributes to arousal, which is misattributed to the frustrating situation. A limitation is that not all aggression stems from frustrated goals (e.g. instrumental aggression for material gain) and not all frustration leads to aggression (e.g. learned helplessness).
Q: Five people witness a person collapse on the street. Nobody calls for help. Explain this using both diffusion of responsibility and pluralistic ignorance.
A: Diffusion of responsibility: each person assumes someone else will take action, reducing their individual sense of obligation. Pluralistic ignorance: each person looks at the others, sees no one reacting, and concludes the situation must not be an emergency. Together, these processes mean that the more bystanders present, the less likely any one individual is to act.
Q: Explain how dehumanisation facilitates aggression, and give one example from the course material.
A: Dehumanisation involves construing others as less than human, either by denying human nature (emotions) or human uniqueness (culture, civility). This removes the moral barrier to aggression, because harming someone perceived as subhuman produces less guilt. Ingroup loyalty can intensify this process: strong identification with one's own group can lead to viewing outgroup members as less than fully human, rationalising violence against them.
Social rejection as a trigger for aggression connects to the need to belong (Ch. 10). Deindividuation (Ch. 12) explains mob aggression. Dehumanisation links to infrahumanisation and stereotyping (Ch. 6, 11). The bystander effect and pluralistic ignorance are direct applications of the same concept from Ch. 4 (social cognition). Obedience (Milgram/Burger) ties back to the fundamental attribution error (Ch. 5): observers attribute obedience to character, but the situation is the primary driver.
Aggression, hostile aggression, instrumental aggression, frustration-aggression model, anger, dehumanisation, culture of honour, precarious manhood hypothesis, media violence, copycat violence, social rejection, ostracism, inequality, Gini index, cognitive control, venting, rape-prone cultures, stepfamily violence, relational aggression, psychopathy, reactive devaluation, restorative justice, altruism, empathy, personal distress, empathetic concern, bystander effect, Kitty Genovese, diffusion of responsibility, pluralistic ignorance, kin selection, reciprocity, cooperation, Prisoner's Dilemma, tit-for-tat, Ultimatum Game, obedience, Milgram, Burger 2009, authority, foot-in-the-door, urban overload