Cause Effect

# Archetype: cause_effect

This question must ask WHY or WHAT CAUSES something. The correct answer is the
underlying mechanism; distractors are adjacent secondary mechanisms that sound
plausible but are not the primary cause.

Examples of stems (deliberately non-default-repertoire — the default-repertoire picks like
"Why does popcorn pop?" / "Why is the sky blue?" / "Why do flamingos stand
on one leg?" are listed in default-repertoire.txt and must be avoided):
- "Why does the night sky look dark despite billions of stars?" (Olbers')
- "Why do bridges sway in unusual wind patterns?"
- "Why does cut wood smell different from living wood?"

## Length budget (mobile UI — cause_effect has the worst answers)
2026-05-05 audit: cause_effect answers had p90=83 chars and p99=107 — the
worst answer-length distribution of any archetype. The pattern: answers
read like full-sentence explanations ("Water trapped inside the kernel
turns to steam, bursting the hull"). Compress them.

- Question: ≤150 chars. Aim for ≤80.
- Each answer: ≤60 chars. Aim for ≤45. Answers should be MECHANISM names
  in noun-phrase form ("Trapped water flashing to steam"), not narrative
  sentences.

Distractor rule: each wrong answer should be a real, related mechanism — never
a random unrelated factor. The player should feel they're choosing between
several plausible explanations and weighing them.

Hard rule: the question MUST start with "Why" or "What causes". The correct
answer is exactly ONE primary causal mechanism — never a list, never a hedged
"a combination of factors". Distractors are SECONDARY mechanisms that exist in
the topic but aren't the primary driver of the effect.

Mechanism-specificity rule: the correct answer must name a SPECIFIC mechanism
in noun-phrase form, not a generic field name. Reject one-word answers like
"evolution", "gravity", "photosynthesis", "thermodynamics" — those are
disciplines, not mechanisms. Acceptable: "convergent evolution under shared
selection pressure", "buoyant force exceeding weight", etc.

Contrast examples:
KEEP — "Why do mosquitos bite some people more than others?"
  correct: "CO2 + skin-microbe scent profile signal a richer blood meal"
  distractors: "Body temperature is slightly higher",
    "Sweat-lactic-acid concentration is mildly attractive",
    "Blood-type O is preferred over A or B"
  why it works: all distractors are real partial-truths, the correct answer
  names the specific mechanism (CO2 + microbe scent), defeatable gradient.

REJECTED — "Why is the ocean salty?"
  correct: "Because ocean water is salty"
  why rejected: explanation restates the answer, distractors not specified;
  no causal mechanism reasoning. Regenerate.

REJECTED — "Why does popcorn pop?" (any variant)
  why rejected: default-repertoire default-repertoire stem (see default-repertoire.txt). Every model
  defaults here — pool saturation guaranteed.