Heuristics, Probability & Judgment
Why do efficient mental shortcuts sometimes produce predictable mistakes?
Retrieval Warm-Up
Without notes, write one idea you already know that might connect to Heuristics, Probability & Judgment. Then write one question the lesson should help you answer.
Essential Question
Why do efficient mental shortcuts sometimes produce predictable mistakes?
Learning Objectives
- Explain heuristics as efficient rules of thumb rather than automatic errors.
- Distinguish availability and representativeness heuristics.
- Explain why base rates matter when judging probability.
- Introduce anchoring as a starting-point influence on estimation.
- Compare intuitive judgment with measured evidence.
heuristic
Vocabulary in Context
heuristic · availability heuristic · representativeness heuristic · base rate · probability · anchoring · intuition · judgment
Substantial Core Reading
Heuristics reduce cognitive effort and often work well, especially in familiar environments. Their efficiency can also produce systematic error when vivid examples replace frequency information, resemblance replaces base rates, or arbitrary starting values influence estimates.
Worked Example / Synthesis
A school has 900 students in a general program and 100 in a robotics program. A fictional description sounds “robotics-like.” Students must combine resemblance with the 90/10 base-rate information rather than treating the description as decisive.
Psychological Scientist's Desk
Evaluate: “Gut instinct is always irrational.”
A better conclusion is that intuition can be highly useful in familiar environments with repeated meaningful feedback, but intuitive judgment can also be biased or poorly calibrated.
Data Lens
Use a simple population table to calculate or compare base rates, then inspect how judgments change after an ambiguous descriptive cue is added. Separate the actual probability information from participants’ estimates.
Claims Laboratory
Calibrate this claim: “One observation about Heuristics, Probability & Judgment tells us everything important about a person.”
Guided Investigation
Probability Stories: analyze six fictional judgments. Identify availability, representativeness, anchoring, base-rate information, or insufficient evidence.
Independent Assignment
Find or construct one public-style risk claim where vivid examples could distort perceived frequency. State what denominator or base-rate information would make the claim easier to evaluate.
Research Notebook Checkpoint
Could availability, category expectations, anchoring, or base-rate neglect distort how participants answer or interpret the semester research question? Identify one safeguard.
Academic Journal Reflection
Why is it more accurate to describe heuristics as trade-offs than simply as mistakes?