Social-contract framing turns hard logic into easy logic

Correct: B — A social-contract rule about benefit and cost (e.g., 'If you take the benefit, you must pay the cost')

Across multiple experiments, Cosmides (1989) reported that abstract Wason selection tasks ('If a card has a vowel on one side, it has an even number on the other') yielded the standard ~10% solution rate, while the same logical structure framed as a social contract ('If you eat the cookie, you must wash the dishes') jumped to ~70%. She argued the dissociation reflects a domain-specific cheater-detection module shaped by selection pressures around reciprocal exchange. The result remains a central data point in evolutionary-psychology and dual-process accounts of reasoning, even as alternative explanations (deontic logic, pragmatic schemas) continue to compete.