T3: Benchmarking Sycophancy and Skepticism in Causal Judgment
Edward Y. Chang
TL;DR
T3 (Testing Trustworthy Thinking) introduces a diagnostic benchmark to evaluate LLM causal judgment across Pearl's Ladder of Causality, decomposing performance into Utility and Safety and incorporating Wise Refusal on AMBIGUOUS cases. It uses 454 expert-curated vignettes to reveal distinct failure modes, including the Skepticism Trap and a Scaling Paradox on counterfactuals, and demonstrates that a process-verified protocol (RCA) can restore decisive causal judgment. The framework combines three prompting protocols to separate capability from robustness and provides a rigorous Sheep/Wolf analysis to expose safety-driven refusals and endorsements. The findings have implications for alignment and benchmarking, showing that safety tuning can trade off genuine causal reasoning and that structured verification can mitigate these pathologies. Overall, T3 offers a granular, diagnostic tool for improving trustworthy causal reasoning in LLMs and guiding future alignment research.
Abstract
We introduce T3 (Testing Trustworthy Thinking), a diagnostic benchmark designed to rigorously evaluate LLM causal judgment across Pearl's Ladder of Causality. Comprising 454 expert-curated vignettes, T3 prioritizes high-resolution failure analysis, decomposing performance into Utility (sensitivity), Safety (specificity), and Wise Refusal on underdetermined cases. By applying T3 to frontier models, we diagnose two distinct pathologies: a "Skepticism Trap" at L1 (where safety-tuned models like Claude Haiku reject 60% of valid links) and a non-monotonic Scaling Paradox at L3. In the latter, the larger GPT-5.2 underperforms GPT-4-Turbo by 55 points on ambiguous counterfactuals, driven by a collapse into paralysis (excessive hedging) rather than hallucination. Finally, we use the benchmark to validate a process-verified protocol (RCA), showing that T3 successfully captures the restoration of decisive causal judgment under structured verification.
