- Explain System 1 vs System 2 thinking
- Describe key cognitive biases
- Apply bias awareness to decisions
Thinking and Biases
Answer quickly: a bat and ball cost £1.10; the bat costs £1 more than the ball. How much is the ball? If you said 10p, your fast brain just tricked you (it’s 5p).
A cognitive bias is a systematic pattern of deviation from rationality — the brain’s shortcuts (heuristics) applied where they mislead, like judging likelihood by how easily examples come to mind.
Key points
- System 1: fast, intuitive, emotional. System 2: slow, analytical, effortful.
- Confirmation bias: we notice evidence that agrees with us.
- Availability heuristic: vivid events feel more likely than they are.
- Anchoring: the first number you hear drags your estimate toward it.
Plane crashes make the news; car crashes don’t. The availability heuristic makes flying feel dangerous, though per kilometre it’s far safer than driving.
Practice
They ignore base rates: if the disease is rare, most positives are false positives — accuracy alone doesn’t give your personal probability.
Deliberately seek disconfirming evidence; argue the opposing case as strongly as you can before deciding.
- Fast thinking is efficient but biased.
- Biases include confirmation, availability and anchoring.
- Knowing about biases doesn’t remove them — but systems (checklists, base rates) help.
- Good reasoning is a skill, not just intelligence.