Primary results

Simulated pilot

Synthetic-agent data only, used to validate the analysis pipeline. Never evidence about human behavior.

905 of 975 synthetic trials included (70 excluded per the preregistered exclusion rules) · study id biasmarket-primary-v1 · generated 2026-09-08

H1 -- Choice share of Product A

logistic (GLM binomial): choice_A ~ condition, n=905. Estimate in log-odds; two pre-declared pairwise contrasts, Bonferroni-corrected.

0 (log-odds, no effect)Biased AI vs Controlsignificant at α=0.025 (p=0.006)0.46Biased AI vs Neutral AIsignificant at α=0.025 (p=0.001)0.53

Belief error (battery life, hours)

OLS (HC3 robust SE): belief_error ~ condition, n=905. Positive estimate = larger overestimate of Product A’s battery life relative to Control.

0 (hours, no effect)Biased AI vs Controlsignificant at α=0.025 (p=<.001)3.50Biased AI vs Neutral AIsignificant at α=0.025 (p=<.001)3.70

Willingness to pay for Product A (USD)

OLS (HC3 robust SE): wtp_A ~ condition, n=905. Self-reported, not incentive-compatible (see /methods).

0 (USD, no effect)Biased AI vs Controlnot significant at α=0.025 (p=0.144)$1.85Biased AI vs Neutral AIsignificant at α=0.025 (p=<.001)$4.23

Note the asymmetry: Biased-vs-Neutral is significant here while Biased-vs-Control is not -- reported as-is, not smoothed into a uniform story across outcomes.

H6 -- Moderation by baseline AI trust

logistic (GLM binomial): choice_A ~ condition * baseline_trust_centered, n=905. Interaction term: condition[T.biased_ai]:baseline_trust_centered.

0.24595% CI [-0.057, 0.547], p=0.112not significant at corrected alpha

In this synthetic run, the biased-AI effect on choice does not significantly vary with baseline AI trust at the Bonferroni-corrected threshold -- H6 is not supported here, reported without re-specifying the model.

This is synthetic-agent data.

Every number above comes from analysis/simulate.py’s rule-based agent population, used only to validate that randomization, persistence, and the confirmatory analysis pipeline work end-to-end before any human is recruited. It is never evidence about actual human behavior. See research/claims_registry.md and research/limitations.md.