Course · Thinking skills

Think Like a Detective: Logic and Thinking Errors

Cognitive biases, logical fallacies, probability and intuition, manipulation, and techniques for clear thinking — a trainer built on real-life cases.

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PepelenCourse author

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Unit 1. The brain lies: illusions and snap judgments

Lesson 1. Two systems of thinking

6 exercises · Understand that thinking works in two modes (fast and slow), and why the fast mode is the source of most errors.

Lesson 2. Proof: the brain fools the eye

9 exercises · See in classic optical illusions that perception is not a “photograph of reality” but something the brain constructs, and confirm it by measuring.

Lesson 3. Snap judgments about people and the world

5 exercises · Understand that instant judgments (about intelligence, risk, causes) are also built by System 1 — and it errs just as systematically as the eye does with illusions.

Unit 2. Biases: how we fool ourselves

Lesson 1. Confirmation: we only look for “pros”

5 exercises · Understand confirmation bias — why we look for facts that confirm our view and miss the ones that refute it, and how to check for it.

Lesson 2. Anchoring and availability

5 exercises · Understand the anchoring effect (the first number pulls your estimate toward it) and the availability heuristic (what's easier to recall seems more common).

Lesson 3. Survivorship bias

6 exercises · Understand survivorship bias — why it's dangerous to learn only from successes and visible cases while missing the “dead” data.

Unit 3. Logical fallacies in arguments

Lesson 1. Red herring and straw man

5 exercises · Learn to recognize the red herring and the “straw man” technique — when a distorted argument is attacked instead of the real one.

Lesson 2. Ad hominem and false dilemma

5 exercises · Recognize personal attacks (ad hominem) and the forced “either-or” choice (false dilemma).

Lesson 3. More tricks and training your eye

5 exercises · Add more common fallacies (appeal to popularity, appeal to authority, slippery slope, “after this, therefore because of this”) and practice finding several fallacies in one argument.

Unit 4. Probability and intuition

Lesson 1. The gambler's fallacy and randomness

5 exercises · Understand why we have a poor feel for randomness: the gambler's fallacy, belief in “the law of streaks”, and the idea that random things should “look random”.

Lesson 2. Base rates and rare events

5 exercises · Understand the base rate fallacy through the “paradox” of a disease test: why even an accurate test for a rare disease is often wrong.

Lesson 3. Less is not always more likely

5 exercises · Understand the conjunction fallacy (the Linda problem) and tie together all the “probability” biases of the unit.

Unit 5. Manipulation: how they push our buttons

Lesson 1. Advertising tricks

5 exercises · See how advertising uses the biases we've covered: scarcity, social proof, the anchor price, the halo, and the decoy.

Lesson 2. Propaganda and information hygiene

5 exercises · Recognize propaganda techniques (labels, the enemy image, the “us versus them” false dilemma, repetition) and apply a basic information check.

Unit 6. Good decisions: techniques for clear thinking

Lesson 1. Checklists against biases

5 exercises · Master practical techniques for clear thinking: the pre-mortem, devil's advocate, the outside view (base rates), and the five-question checklist.

Lesson 2. Detective training: mixed cases

6 exercises · Consolidate the skill on mixed cases: quickly identify the bias or fallacy in different situations.

Lesson 3. The detective's final test

7 exercises · Take the final check: recognize the biases and fallacies in a set of cases and put it all together into one big picture.