C4
CalibrationConjunction Fallacy
Joint probability should not exceed marginal probability
4
Models Tested
1
Confirmatory
-0.325
Mean Effect
0.979
Max Effect
Theoretical Context
Theoretical Anchor
Tversky & Kahneman (1983)
Normative Violation
Joint probability should not exceed marginal probability
Cross-Model Comparison
Effect sizes for Conjunction Fallacy across all tested models
Anthropic
Claude Sonnet 4.6
The Cautious Contrarian
h = -0.979Confirmatory
OpenAI
GPT-5.3 Instant
The Directive Optimist
h = -0.373
Google
Gemini 2.0 Flash
The Consistent Optimist
h = +0.246
OpenAI
GPT-5.5
The Invariant
h = -0.196
Statistical Details
Full results with confidence intervals and sample sizes
| Model | n (A) | n (B) | Cohen's h | 95% CI | Status |
|---|---|---|---|---|---|
| Claude Sonnet 4.6 | 50 | 50 | -0.9785 | — | Confirmatory |
| GPT-5.3 Instant | 50 | 50 | -0.3729 | — | Exploratory |
| Gemini 2.0 Flash | 50 | 50 | +0.2460 | — | Exploratory |
| GPT-5.5 | 50 | 50 | -0.1957 | — | Exploratory |