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arXiv 2601.04436cs.CL
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学习模拟人类对话

Learning to Simulate Human Dialogue

Stanford University(斯坦福大学)

Kanishk Gandhi, Agam Bhatia, Noah D. Goodman

AI总结:

本文研究了通过直接最大化真实人类对话的对数概率来提高对话预测效果,发现基于评判者奖励的方法在某些情况下表现不佳,而直接优化对数概率能更准确地预测人类对话。

摘要:

要预测某人会说什么,就是建模他们如何思考。我们通过下一句对话预测来研究这一问题:给定一段对话,预测一个人产生的下一句发言。我们从两个维度比较学习方法:(1)模型是否允许在回应前思考,以及(2)学习如何通过一个LLM作为评判者来评分语义相似性和信息完整性,相对于真实响应,或者通过直接最大化真实人类对话的对数概率。我们发现,优化基于评判者的奖励确实会提高评判分数,但会降低对真实人类响应的对数概率和当人类评判者在真实和合成选项中选择最人类化响应时的胜率。这种失败在模型允许在回答前思考时被放大。相反,通过直接最大化观察到的人类响应的对数概率,模型学会更好地预测人们实际上说什么,从而在对数概率和胜率评估上都取得改进。将思维链视为一个潜在变量,我们推导出对数概率的下界。优化这个目标在我们所有的评估中都取得了最佳结果。这些结果表明,思考主要在以基于真实人类对话的分布匹配目标进行训练时有所帮助,并且将这种方法扩展到更广泛的对话数据可能产生对人类行为有更细致理解的模型。

英文摘要:

To predict what someone will say is to model how they think. We study this through next-turn dialogue prediction: given a conversation, predict the next utterance produced by a person. We compare learning approaches along two dimensions: (1) whether the model is allowed to think before responding, and (2) how learning is rewarded either through an LLM-as-a-judge that scores semantic similarity and information completeness relative to the ground-truth response, or by directly maximizing the log-probability of the true human dialogue. We find that optimizing for judge-based rewards indeed increases judge scores throughout training, however it decreases the likelihood assigned to ground truth human responses and decreases the win rate when human judges choose the most human-like response among a real and synthetic option. This failure is amplified when the model is allowed to think before answering. In contrast, by directly maximizing the log-probability of observed human responses, the model learns to better predict what people actually say, improving on both log-probability and win rate evaluations. Treating chain-of-thought as a latent variable, we derive a lower bound on the log-probability. Optimizing this objective yields the best results on all our evaluations. These results suggest that thinking helps primarily when trained with a distribution-matching objective grounded in real human dialogue, and that scaling this approach to broader conversational data may produce models with a more nuanced understanding of human behavior.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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