Difficulty: Intermediate | Prerequisites: Parts 1–3 (Intro, Research Methods, Personality, The Self, Motivations, Social Judgments, Attitudes, Social Norms, Conformity).
This final cluster covers how people are persuaded to change their minds, why people aggress, and how we form impressions of others. Persuasion builds directly on the attitudes and conformity material: the same principles (cognitive dissonance, normative pressure, heuristic processing) underpin persuasion techniques. Aggression theories draw on the nature-vs.-nurture framework from Part 1 and the social learning principles that run through the entire course. Perception ties together attribution, heuristics and cultural factors into a unified account of how we size people up. If you have kept up with Parts 1–3, this material will feel like a natural extension.
Persuasion works through two routes: central (argument quality) and peripheral (surface cues like attractiveness). Compliance techniques (foot-in-the-door, door-in-the-face, lowball) exploit commitment and reciprocity. Aggression is not purely instinctual; it is shaped by frustration, cues, social learning and media exposure. Perception relies on rapid, often biased impressions: we judge others on warmth and competence, use thin slices of information, and default to categorising by race, gender and age.
Elaboration Likelihood Model (ELM)
A dual-process model of persuasion. The central route involves careful evaluation of arguments; the peripheral route relies on surface cues.
Central Route
Persuasion through the strength of the argument itself. Produces more enduring attitude change.
Peripheral Route
Persuasion through incidental cues (speaker attractiveness, expertise, number of arguments). Produces quicker but less durable change.
Foot-in-the-Door Technique
Getting someone to agree to a small request first, which increases the likelihood they will agree to a larger request later.
Door-in-the-Face Technique
Starting with a large request that will be refused, then following with a smaller (actual) request. The contrast makes the second request seem reasonable.
Lowball Technique
Getting someone to commit to an attractive offer, then switching to a less attractive version. The initial commitment tends to hold.
Halo Effect
Judging someone as good in many ways based on a single positive trait (e.g. physical attractiveness leads to assumptions of intelligence, kindness).
Attitude Inoculation
Building resistance to persuasion by exposing someone to weak versions of an argument beforehand. Like a vaccine for the mind.
Psychological Reactance (in Persuasion)
When persuasion feels like a threat to freedom, people push back. Heavy-handed messages can backfire.
Heuristic-Systematic Model
People want to form correct attitudes that express their values and boost their social image, but they use as little cognitive energy as possible to get there.
The ELM is the central framework for understanding persuasion.
Central route – the audience is motivated and able to think carefully about the message. Argument quality matters. Attitude change tends to be lasting.
Peripheral route – the audience is distracted, uninterested or unable to process deeply. Surface cues (speaker attractiveness, number of arguments, credentials) drive persuasion. Change is quicker but less stable.
Which route a person takes depends on motivation (personal relevance, knowledge of the topic) and ability (whether they are distracted, tired, etc.).
The communicator:
Credibility (expertise + trustworthiness) increases persuasion.
Attractiveness matters: physical attractiveness, similarity to the audience and the halo effect all boost influence.
The halo effect means one positive trait (e.g. good looks) leads people to assume other positive traits (smart, kind, honest).
The message:
Compliance techniques exploit commitment dynamics:
Foot-in-the-door – agree to something small, then something bigger follows
Lowball – commit to a good deal, then the terms change (but you stay committed)
Door-in-the-face – refuse something big, then a smaller request feels reasonable
Two-sided arguments (acknowledging the opposition, then countering) are more persuasive with informed audiences.
Primacy effect – first arguments have more impact when messages are back-to-back.
Recency effect – later arguments have more impact when there is a delay between messages.
The channel:
Face-to-face communication is generally more persuasive than written or recorded messages.
Speaker style (confidence, pacing, eye contact) matters.
The audience:
Motivation and ability determine which route is taken.
Age effects: attitudes change across the lifespan (life cycle explanation) and across generations (generational explanation).
Mood spillover: a positive mood makes people more receptive to persuasion.
Matching the message to the audience's identity increases its impact.
Attitude inoculation – exposure to weakened counterarguments builds resistance to stronger versions later. This is the psychological equivalent of a vaccine.
Counterarguing – actively generating reasons why the persuasive message is wrong.
Psychological reactance – when people feel their freedom of choice is threatened, they resist more strongly and may move in the opposite direction (boomerang effect).
Aggression
The intentional infliction of physical, emotional or psychological pain on another person. The key word is intentional: accidental harm is not aggression.
Hostile Aggression
Aggression where the ultimate goal is to inflict pain. The harm is the point.
Instrumental Aggression
Aggression used as a means to achieve some other goal. The harm is a tool, not the end.
Frustration-Aggression Theory
The original (overly simple) claim that frustration always leads to aggression and aggression always stems from frustration. Later revised: frustration leads to aggression only when it produces anger.
Aggression Cues Theory
Frustration alone is not enough. An environmental cue associated with aggression (e.g. the presence of a weapon) must also be present.
Social Learning Theory (Bandura)
Aggression is learned by observing others being rewarded for it (observational learning) or by being rewarded for it yourself (direct reinforcement). The Bobo doll study is the classic demonstration.
Desensitisation
Repeated exposure to violent media reduces the typical emotional arousal response to violence.
Hostile aggression – the goal is harm itself (e.g. punching someone out of rage).
Instrumental aggression – harm is a means to another end (e.g. a robber threatens violence to get money).
Honour-restorative violence – aggression motivated by perceived threats to one's reputation or honour.
Instrumental violence – violence in pursuit of a goal (power, resources, territory).
Random violence – seemingly unprovoked or unpredictable.
Instinctual and biological approaches:
The instinct view (aggression is innate and universal) has three problems: circularity (it explains aggression by saying we are aggressive), empirical failure (aggression varies enormously across cultures and individuals) and over-generality.
Biological factors (heredity, brain structure, hormones like testosterone) do contribute, but they explain specific acts, not aggression as a whole.
Social-psychological theories:
Frustration-aggression theory – frustration produces aggression. The original version overstated the link. Later research showed frustration leads to aggression only when it also produces anger.
Aggression cues theory – frustration creates readiness for aggression, but an external cue (e.g. a weapon in the room) is needed to trigger it.
Social learning theory – aggression is learned through direct reinforcement (being rewarded for aggression) and observational learning (watching others be aggressive and seeing it pay off). Bandura's Bobo doll studies showed that children who watched an adult model behave aggressively toward a doll were more likely to imitate that behaviour.
Imitation – people imitate behaviours they see modelled, especially when those behaviours are portrayed as desirable or rewarded.
Priming – consuming violent media activates aggression-related thoughts, making violent responses more mentally accessible.
Desensitisation – repeated exposure to media violence dulls the normal emotional response, making aggression feel less alarming.
Perceived threat
Competition for resources or status
Rewards and punishment (aggression can be reinforced by higher status or dominance)
Systemic factors: uneven power dynamics, lack of accountability (e.g. online anonymity)
Perceiver Effects
The average judgment a particular perceiver makes compared to other perceivers. Some people are generally harsher or more generous raters.
Target Effects
The average judgment all perceivers make of a particular target. Some people simply make stronger impressions.
Relationship Effects
The unique judgment a specific perceiver makes of a specific target that cannot be explained by perceiver or target effects alone.
Gestalt
An organised whole that is perceived as more than the sum of its parts. In person perception, we see a face as a unified impression, not as separate features.
Universal Emotion Recognition
Six emotions are recognised across cultures through facial expressions: happiness, surprise, fear, disgust, anger and sadness.
Thin-Slice Judgments
Forming impressions based on very brief exposure to a person (seconds of behaviour). Surprisingly often accurate for some traits.
Warmth
One of the two primary dimensions of person perception. Does this person have good intentions toward me?
Competence
The second primary dimension. Can this person carry out those intentions? Can they help me?
When you judge someone, the impression reflects three things:
Perceiver effects – your general tendency as a rater (generous, harsh, etc.)
Target effects – something about the person that most people pick up on
Relationship effects – your unique reaction to this particular person, beyond what can be explained by the first two
We perceive faces as unified wholes (gestalts), not as collections of separate features. This is why slight changes to a face (a different expression, a new hairstyle) can dramatically shift our overall impression.
Research across cultures has identified six basic emotions that are recognised through facial expressions regardless of cultural background: happiness, surprise, fear, disgust, anger and sadness.
We call on memory to make judgments, often using priming (recent exposure to a concept makes it more accessible).
We rely on shortcuts to form impressions, including stereotypes.
Thin-slice judgments – we form impressions from very brief behavioural samples. These are often surprisingly accurate for traits like extraversion but less reliable for others.
When sizing someone up, people default to two questions:
Warmth – "Does this person have good intentions toward me?" (friend or foe?)
Competence – "Can this person act on those intentions?" (can they help or harm me?)
Warmth is typically assessed first and carries more weight in initial impressions.
When making snap judgments, people rely most heavily on three visible categories: race, gender and age. These categories activate stereotypes that colour subsequent perception, often unconsciously.
Students often think the central route is always "better" than the peripheral route. Both routes are effective in different contexts. The peripheral route is not inferior; it is simply suited to low-involvement situations.
Students sometimes assume the frustration-aggression hypothesis means all frustration leads to aggression. The revised view is that frustration leads to aggression only when it produces anger, and often only in the presence of aggression cues.
Students frequently confuse hostile and instrumental aggression. A useful test: ask whether the person's primary goal is to cause pain (hostile) or to achieve something else through pain (instrumental).
Students tend to think person perception is mainly visual. While appearance matters, memory, priming and prior stereotypes play equally large roles in shaping impressions.
⚠️ The Elaboration Likelihood Model is heavily tested. Be able to explain both routes, the conditions that activate each and why central-route change is more durable.
⚠️ Know the three compliance techniques (foot-in-the-door, door-in-the-face, lowball) and be able to identify which one is at work in a scenario.
⚠️ Be prepared to compare the three social-psychological theories of aggression (frustration-aggression, aggression cues, social learning) and their limitations.
⚠️ The Bobo doll study (Bandura, Ross and Ross) is a classic. Know what it demonstrated and how it supports social learning theory.
⚠️ Understand warmth vs. competence as the two primary dimensions of person perception. Expect a question asking which is assessed first (warmth).
⚠️ Know the six universally recognised emotions and be able to name them.
True or False: The peripheral route to persuasion produces more lasting attitude change than the central route. (False. The central route produces more durable change.)
Name the three compliance techniques covered in this unit. (Foot-in-the-door, door-in-the-face, lowball.)
True or False: According to the frustration-aggression hypothesis, frustration always leads to aggression. (False. The revised view is that frustration leads to aggression only when it also produces anger.)
What two dimensions do people use first when judging others? (Warmth and competence.)
Name the six universally recognised emotions. (Happiness, surprise, fear, disgust, anger, sadness.)
Q: A charity asks you to sign a petition (small request), then follows up a week later asking for a monetary donation (larger request). Which compliance technique is this?
A: Foot-in-the-door. By getting you to agree to something small first, they increase the likelihood you will agree to the larger follow-up request.
Q: A car dealer offers a great price, you agree, and then the dealer adds fees that raise the total. You still buy the car. What technique is this?
A: The lowball technique. Once you have committed to the initial offer, switching to less favourable terms does not reliably break that commitment.
Q: Explain the difference between hostile aggression and instrumental aggression, and give an example of each.
A: Hostile aggression aims to inflict harm for its own sake (e.g. punching someone in a rage). Instrumental aggression uses harm as a means to another goal (e.g. a bully intimidating a classmate to take their lunch money).
Q: What did Bandura's Bobo doll study demonstrate?
A: Children who watched an adult model behave aggressively toward an inflatable doll were significantly more likely to imitate that aggression when given the opportunity. This supports social learning theory: aggression can be learned through observation, not just direct experience.
Q: When you meet someone new, research suggests you assess two dimensions almost immediately. What are they, and which comes first?
A: Warmth ("Does this person mean well?") and competence ("Can this person act on their intentions?"). Warmth is typically assessed first and carries more weight in the initial impression.
Q: A political campaign runs a series of advertisements featuring a celebrity endorser but provides little policy detail. Which route to persuasion are they using, and when is this strategy most effective?
A: The peripheral route. Celebrity endorsement is a surface cue, not an argument. This strategy works best when the audience is low in motivation or ability to process the message carefully (distracted, uninterested or uninformed).
The ELM's two routes map directly onto the System 1/System 2 distinction from Social Beliefs and Judgments (Part 2). Compliance techniques (foot-in-the-door, lowball) rely on the same commitment dynamics as cognitive dissonance. The halo effect in persuasion connects to the thin-slice and stereotype-based judgments in Perception. Aggression theories' emphasis on social learning ties back to Bandura's broader work, which also informs how attitudes are acquired through observation. The warmth-competence framework in Perception connects to the attribution material from Part 2: perceiver effects are influenced by the same heuristics and biases covered under social judgments.
Persuasion, Elaboration Likelihood Model, ELM, central route, peripheral route, dual-process persuasion, foot-in-the-door, door-in-the-face, lowball technique, compliance, halo effect, communicator credibility, attractiveness, expertise, trustworthiness, primacy effect, recency effect, attitude inoculation, counterarguing, psychological reactance, boomerang effect, Heuristic-Systematic Model, mood spillover, aggression, hostile aggression, instrumental aggression, honour-restorative violence, frustration-aggression theory, aggression cues theory, social learning theory, Bandura, Bobo doll, observational learning, direct reinforcement, media violence, imitation, priming, desensitisation, perception, perceiver effects, target effects, relationship effects, Gestalt, universal emotion recognition, six basic emotions, happiness, surprise, fear, disgust, anger, sadness, thin-slice judgments, warmth, competence, race, gender, age, Big Three categories, stereotypes, person memory