🧠 The Brain That Decides
From Kahneman to cognitive biases: how the human brain processes information, creates mental shortcuts, makes systematic errors, and deals with internal contradictions.
Modules
Topics
Duration
Level
Learning path map
🧠 System 1 and System 2
Kahneman's dual-system model explains why we think too fast
⚡ Heuristics: the shortcuts that mislead
Availability, representativeness, and anchoring: when mental shortcuts mislead us
🗺️ Cognitive Biases
Confirmation, Halo, and Dunning-Kruger: the map of errors we all make
🔄 Cognitive Dissonance
Festinger and the discomfort of living with contradiction: why change is so difficult
Detailed content
System 1 and System 2: Two Ways of Thinking
Daniel Kahneman (2011) · 6 topics
What is
The theory that the brain operates in two distinct modes: one fast and automatic (System 1), the other slow and deliberate (System 2). Proposed by Kahneman and Tversky based on decades of experiments.
Why learn
Understanding this distinction is the foundation for understanding all the biases and judgment errors we’ll study in this course.
Key concepts
Dual processing, automaticity, cognitive effort, selective attention.
What is
Automatic, involuntary, emotional, and parallel processing. Operates in milliseconds, recognizing patterns, faces, and threats. Responsible for ~95% of everyday decisions.
Why learn
Most cognitive errors come from S1 operating in situations that would require S2.
Key concepts
Intuition, associative memory, WYSIATI ("what you see is all there is"), unconscious processing.
What is
Slow, sequential, conscious, and deliberate processing. Requires attention and energy. It is inherently lazy: tends to accept what S1 proposes without checking.
Why learn
Knowing that S2 is limited and fatigable explains why decisions get worse throughout the day.
Key concepts
Focused attention, working memory, ego depletion, cognitive fatigue.
What is
S1 generates impressions, intuitions, and impulses. S2 monitors (weakly) and can veto. When S1 encounters something it can't resolve, it activates S2. But S2 isn't always activated in time.
Why learn
The failure of this interaction is the root of biases: S1 decides quickly, and S2 lazily endorses the decision.
Key concepts
Attribute substitution, associative coherence, cognitive laziness, faulty monitoring.
What is
Marketing exploits S1 (emotional images, .99 prices, music). Poor financial decisions result when S1 acts where S2 should. Judges hand down harsher sentences after hours of work.
Why learn
Recognizing when S1 is being exploited is the first step toward better decisions.
Key concepts
Priming, framing, decision fatigue, nudge (introduction).
What is
Kahneman, an Israeli-American psychologist, received the Nobel Prize in Economics in 2002 for demonstrating that humans are not rational agents. His book "Thinking, Fast and Slow" (2011) synthesizes decades of research with Amos Tversky.
Why learn
Provide context on the intellectual origins of the dual model and understand the academic and practical impact of these findings.
Key concepts
Economic psychology, Prospect Theory, bounded rationality, Kahneman-Tversky contribution.
Heuristics: the shortcuts that mislead us
Kahneman & Tversky · 6 topics
What is
Simplified mental strategies the brain uses to make quick decisions under uncertainty. They’re evolutionary adaptations, not "bugs".
Why learn
They are the bridge between S1 (which operates through shortcuts) and biases (which are shortcuts applied in the wrong contexts).
Key concepts
Adaptive heuristics, ecological rationality, Gigerenzer vs. Kahneman.
What is
We estimate the probability of something by how easily examples come to mind. After shark attack stories, we overestimate the risk (lightning kills more people). Social networks exploit this.
Why learn
Governments, media, and platforms manipulate availability to distort risk perception.
Key concepts
Retrieval fluency, salience bias, disproportionate fear, media as an amplifier.
What is
We classify by resemblance to a prototype, ignoring statistics. “Shy, organized Steve” seems like a librarian, but there are more farmers in the world.
Why learn
Causes people to overestimate stereotypes and ignore base rates, leading to prejudice and mistaken judgments.
Key concepts
Base rate neglect, conjunction fallacy, Linda problem, stereotyping.
What is
The first number we see anchors all subsequent evaluations. Roulette experiment: those who spun 10 estimated 25 African countries in the UN; those who spun 65 estimated 45.
Why learn
Negotiations, prices, salaries: whoever anchors first controls the outcome.
Key concepts
Anchoring effect, insufficient adjustment, decoy pricing, first bid.
What is
We judge risks and benefits based on feelings, not data. If something seems good to us, we minimize the risks. If it seems bad, we exaggerate the dangers.
Why learn
Explains investment decisions, support for public policies, and acceptance of technologies based on “gut feeling.”
Key concepts
Affect heuristic, emotional evaluation, perceived vs. actual risk, Paul Slovic.
What is
Heuristics are efficient in stable, familiar environments (an experienced firefighter “senses” danger). They fail in complex, unfamiliar environments or when feedback is delayed (financial markets, politics).
Why learn
Knowing how to distinguish contexts where heuristics are appropriate from those where they aren't is the metacognition that separates good decisions from terrible ones.
Key concepts
High- and low-validity environments, expert intuition, feedback loops, strategic deliberation.
Cognitive biases: the map of systematic errors
Kahneman, Dunning, Kruger · 6 topics
What is
Systematic patterns of deviation from rationality. They are not random: they are predictable, universal, and persistent even when we know they exist.
Why learn
Mapping biases is the first step toward building countermeasures (debiasing).
Key concepts
Bias vs. noise, systematic error, bias taxonomy, codex of cognitive biases.
What is
Searching for, interpreting, and remembering only what confirms existing beliefs. The brain releases dopamine when beliefs are confirmed; dissonance causes discomfort that we avoid.
Why learn
Social media algorithms amplify confirmation bias, creating epistemic bubbles (Bruzzo).
Key concepts
Selective exposure, selective interpretation, selective memory, filter bubbles.
What is
One positive trait (beauty, status) influences the perception of all the others. Texts were rated as more intelligent when the author's photo was attractive.
Why learn
Affects hiring, elections, legal judgments, and product evaluation.
Key concepts
Halo effect, horn effect (reverse), first impressions, competence attribution.
What is
Those who know little overestimate their competence; those who know a lot underestimate it. Incompetence impairs metacognition. Russell: “idiots full of certainty, intelligent people full of doubt.”
Why learn
Social media gave a megaphone to the phase of maximum confidence with minimum competence.
Key concepts
Metacognition, 4 stages of competence, illusion of superiority, calibration.
What is
The same information leads to opposite decisions depending on how it's presented. "90% survival" sounds better than "10% mortality," even though they are identical.
Why learn
Framing is one of the most powerful tools of manipulation, used by politicians, salespeople, and algorithms.
Key concepts
Positive/negative framing, default bias, opt-out option, information architecture.
What is
Recommendation algorithms intensify existing biases by creating epistemic bubbles. Bruzzo: platforms don’t create biases, but they turn them into permanent infrastructure.
Why learn
The convergence of cognitive biases and technology is the central theme of this course and Track 6.
Key concepts
Filter bubbles, echo chambers, algorithmic feedback loops, digital polarization.
Cognitive dissonance and behavior change
Leon Festinger (1957) · 6 topics
What is
A state of psychological discomfort when beliefs, attitudes, or behaviors contradict one another. Festinger (1957) showed that humans are motivated to reduce this internal tension.
Why learn
Dissonance is the hidden engine behind rationalization, denial, and resistance to change.
Key concepts
Dissonance, cognitive consistency, motivation for balance, psychological tension.
What is
4 strategies: change behavior, change beliefs, add reconciling cognition, or reduce the perceived importance of the conflict.
Why learn
Knowing how the brain "resolves" contradictions reveals why people rationalize instead of changing.
Key concepts
Rationalization, minimization, reconciliation, attitude change.
What is
Participants paid $1 to lie ("the task was fun") genuinely changed their opinions; those paid $20 did not. At $1, the dissonance was unbearable: "I lied for almost nothing" forced a change in belief.
Why learn
Demonstrates the paradox: SMALLER rewards lead to GREATER attitude change.
Key concepts
Insufficient justification, internalization, the induced-compliance paradigm.
What is
Informing people about risks fails because it activates defenses against dissonance. Effective strategies: public commitment, small steps, identity change ("I'm healthy" vs. "I'm trying to quit smoking").
Why learn
To persuade genuinely, you need to understand that the path is not information, but identity.
Key concepts
Narrative identity, foot-in-the-door, public commitment, micro-habits.
What is
Fans of leaders rarely change their minds in the face of scandals: they rationalize, minimize, and discredit sources. This explains the resilience of political bases to contrary evidence.
Why learn
Understanding why “facts don’t change opinions” is essential for effective communication and political analysis.
Key concepts
Backfire effect, tribal motivation, social identity, motivated reasoning.
What is
Digital platforms reduce exposure to dissonance by filtering out dissonant content. The result: defenses against dissonance grow stronger, and polarization increases.
Why learn
Connects Festinger (1957) with the contemporary debate about algorithmic polarization (Bruzzo, Sunstein).
Key concepts
Filter bubble, echo chamber, comfort algorithm, asymmetric polarization.