## Problem 320 — rank:293

**Title:** Evolutionary and physiological function of laughter

**Added binding assumptions (LaTeX):**

```latex
Standardize both conditions to the same pretreatment relationship/cultural distribution and account for clustered interactions and interference between participants. Improved prediction from the opioid measurement does not establish mediation or its direction. Define the distinct mediating estimand and assumptions when that claim is made. A current social consequence, even if causal, does not by itself reconstruct why laughter evolved.
```

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