## Problem 318 — rank:263

**Title:** Biological origin of human handedness

**Added binding assumptions (LaTeX):**

```latex
Define the target cohort distribution and integrate the shared family effect consistently in marginal and joint probabilities. A random family effect is not uniquely genetic; cultural transmission, prenatal environment and recruitment can generate similar dependence. Latent preference labels need anchoring by the repeated-task measurement model. Separating causal genetic, developmental and cultural contributions requires supported contrasts, not merely a fitted multinomial decomposition.
```

**Direct edits:** 0. **Fresh external checks:** None; supplied sources retained as provenance.