# Heuristics
Heuristics are mental shortcuts that allow people to make quick decisions and judgments without exhaustive analysis. Studied extensively by [[Daniel Kahneman]] and [[Amos Tversky]], heuristics are the brain's efficient strategies for dealing with complexity and uncertainty. While often useful, they can lead to systematic errors known as [[Cognitive biases]]. Heuristics are a key concept in [[Cognitive Psychology]], [[Behavioral Economics]], and [[Decision Making]] research.
The "heuristics and biases" program demonstrated that humans don't process probability and statistics like rational calculators—instead, we use rules of thumb that work well enough in most situations. [[Gerd Gigerenzer]] later argued that heuristics can be "ecologically rational"—optimal for specific environments. Understanding heuristics helps explain both human intelligence (how we cope with complexity) and human error (when shortcuts fail).
## Major Heuristics (Kahneman & Tversky)
| Heuristic | Description | Bias It Produces |
|-----------|-------------|------------------|
| **Availability** | Judge frequency by ease of recall | Overestimate vivid/recent events |
| **Representativeness** | Judge probability by similarity | Base rate neglect, conjunction fallacy |
| **Anchoring** | Start from initial value, adjust | Insufficient adjustment |
| **Affect** | Let emotions guide judgment | Risk perception distortion |
## Availability Heuristic
```
Ease of Recall → Perceived Frequency
"What's more common: words starting with 'K' or words with 'K' as 3rd letter?"
┌─────────────────────────────────────────────────────────────┐
│ Words starting with K: King, Kitchen, Kite... │
│ (Easy to recall → seems more common) │
│ │
│ Words with K as 3rd letter: Ask, Acknowledge, Baked... │
│ (Harder to recall → seems less common) │
│ │
│ Reality: 3rd-letter K words are MORE common │
└─────────────────────────────────────────────────────────────┘
```
## Representativeness Heuristic
```
The Linda Problem:
"Linda is 31, single, outspoken, and very bright. She majored
in philosophy. As a student, she was deeply concerned with
issues of discrimination and social justice."
Which is more probable?
A) Linda is a bank teller
B) Linda is a bank teller AND active in the feminist movement
┌─────────────────────────────────────────────────────────────┐
│ Most people choose B (conjunction fallacy) │
│ │
│ But: P(A and B) ≤ P(A) always │
│ │
│ The description is "representative" of a feminist, │
│ overriding probability logic │
└─────────────────────────────────────────────────────────────┘
```
## Anchoring Heuristic
| Scenario | Anchor Effect |
|----------|---------------|
| Salary negotiation | First number influences final |
| Real estate | Listing price anchors offers |
| Sentencing | Prosecutor's demand anchors verdict |
| Donations | Suggested amounts anchor giving |
## Fast and Frugal Heuristics (Gigerenzer)
| Heuristic | Rule | When It Works |
|-----------|------|---------------|
| **Recognition** | Choose recognized option | When recognition correlates with quality |
| **Take-the-best** | Use single best cue | When cues have different validity |
| **Tallying** | Count positive features | When cues have equal validity |
| **Satisficing** | Accept "good enough" | When search is costly |
| **1/N** | Divide equally | When prediction is uncertain |
## Heuristics vs Algorithms
| Aspect | Heuristic | Algorithm |
|--------|-----------|-----------|
| **Speed** | Fast | Slow |
| **Effort** | Low | High |
| **Accuracy** | "Good enough" | Optimal |
| **Information** | Partial | Complete |
| **Transparency** | Often unconscious | Explicit |
## Applications
| Domain | Heuristic Use |
|--------|---------------|
| **UX Design** | Recognition heuristics for navigation |
| **Marketing** | Anchoring in pricing |
| **Medicine** | Diagnostic heuristics (and their pitfalls) |
| **AI** | Heuristic search algorithms |
| **Personal** | Decision-making under uncertainty |
## References
- Kahneman, D. (2011). *Thinking, Fast and Slow*
- Gigerenzer, G. (1999). *Simple Heuristics That Make Us Smart*
- https://en.wikipedia.org/wiki/Heuristic
## Related
- [[Cognitive biases]]
- [[Decision Making]]
- [[Behavioral Economics]]
- [[Daniel Kahneman]]
- [[Amos Tversky]]
- [[Gerd Gigerenzer]]
- [[Bounded Rationality]]
- [[Cognitive Psychology]]