12 hours ago
- Heritability is a flexible concept; redefining traits can change heritability estimates dramatically, e.g., hair color or IQ under hypothetical conditions.
- The paper simulates lifespan heritability in a world without non-aging deaths (accidents, etc.), finding it rises from 23-35% (twin studies) to 46-57% in simulation.
- The model uses an 'extrinsic mortality' parameter to adjust for external causes of death; lower extrinsic mortality increases heritability.
- The paper’s unclear writing in Science makes it hard to reproduce, but the modeling is clever for estimating heritability under reduced environmental randomness.
- Actual modern heritability may be around 40% (not 50%) when extrinsic mortality is set to current levels, per the simulation data.
- The author criticizes Science’s style for lacking clarity and scientific rigor in statistics-based papers.