Humansand Launches Persimmon, a Large-Scale Model That Simulates How Real People Talk

alexisjross · x · 2026-09-11

Startup Humansand introduced Persimmon, described as the first large-scale model designed to realistically simulate how people talk and interact — aimed at making AI understand its human collaborators for agent training, personalization evals, and social science research.

The approach echoes the Turing-RL paper (arXiv:2606.19336) by Yingshan Wang, Cedegao E. Zhang et al., who confirmed the connection. Turing-RL trains user simulators with a discriminative Turing reward scored by an LLM judge — rewarding responses indistinguishable from the real user rather than matching a single ground truth — and consistently beats baselines on both LLM and human evaluation across conversational chat and Reddit forum domains. Takeaway: optimizing indistinguishability outperforms response matching.

Related event: Stanford-linked Humans& Launches Persimmon, a Large-Scale Human Simulation Model(19 posts)→

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