Proof Engine Verification: The correlation between human brain volume and intelligence is r = 0.4

Automated fact-verification of the claim: "The correlation between human brain volume and intelligence is r = 0.4" Verdict: PARTIALLY VERIFIED Key Findings SC1 (unconditional overall estimate) — FAILS: Two independent large-scale meta-analyses, Pietschnig et al. (2015) and Nave et al. (2022), both report r = 0.24 for the unconditional brain volume–IQ correlation. The deviation from 0.40 is 0.16, well outside the ±0.05 tolerance. SC2 (conditional estimate: healthy adults, high-quality tests) — PASSES: Wikipedia's Neuroscience and intelligence article (citing Gignac & Bates 2017, Intelligence) states r ≈ 0.40 when high-quality IQ tests are used in healthy adult samples. The r = 0.4 figure is conditionally correct: It holds under optimal measurement conditions, not as a general population-wide average. Publication bias inflates, not deflates: Both major meta-analyses found evidence that published studies overreport high correlations. The true unconditional r is likely ≤ 0.24, not 0.40. Files proof.py — Re-runnable Python verification script proof.md — Structured proof report proof_audit.md — Full verification audit trail proof_narrative.md — Plain-language summary proof.json — Machine-readable structured data Generated by Proof Engine v0.10.0.