How do we evaluate whether someone will make a good friend or collaborative peer? A hallmark of human cognition is the ability to make adaptive decisions based on information garnered from limited prior experiences. Using an interactive social task measuring adaptive choice (deciding who to reengage or avoid) in male and female participants, we find the hippocampus supports value-based social choices following single-shot learning. These adaptive choices elicited a suppression signal in the hippocampus, revealing sensitivity for the subjective perception of a person and how well they treat you during choice. The extent to which the hippocampus was suppressed was associated with flexibly interacting with prior generous individuals and avoiding selfish individuals. Further, we found that hippocampal signals during decision-making were related to subsequent memory for a person and the offer they made before. Consistent with the hippocampus leveraging previously executed choices to solidify a reliable neural signature for future adaptive behavior, we also observed a later hippocampal enhancement. These findings highlight the hippocampus playing a multifaceted role in socially adaptive learning.

SIGNIFICANCE STATEMENT Adaptively navigating social interactions requires an integration of prior experiences with information gleaned from the current environment. While most research has focused on striatal-based feedback learning, open questions remain regarding the role of hippocampal-based episodic memory systems. Here, we show that during social decisions based on prior experience, hippocampal suppression signals were sensitive to adaptive choice, while hippocampal enhancements was related to subsequent memory for the original social interaction. These findings highlight the hippocampus playing a multifaceted role in socially adaptive learning.

我们如何评估某人是否会成为好朋友或合作伙伴？人类认知的一个标志是能够根据从有限的先前经验中获得的信息做出适应性决策。使用测量男性和女性参与者的适应性选择（决定重新参与或避免谁）的交互式社会任务，我们发现海马体支持单次学习后基于价值的社会选择。这些适应性选择在海马体中引发了抑制信号，揭示了一个人主观感知的敏感性以及他们在选择过程中对你的态度。海马体受到抑制的程度与灵活地与先前慷慨的个体互动并避免自私的个体有关。更远，我们发现决策过程中的海马信号与一个人的后续记忆以及他们之前提出的提议有关。与海马体利用先前执行的选择来巩固未来适应性行为的可靠神经特征一致，我们还观察到了后来的海马体增强。这些发现强调了海马体在社会适应性学习中发挥着多方面的作用。

重要性声明适应性地导航社交互动需要将先前的经验与从当前环境中收集的信息相结合。虽然大多数研究都集中在基于纹状体的反馈学习上，但关于基于海马的情景记忆系统的作用仍然存在悬而未决的问题。在这里，我们表明在基于先前经验的社会决策过程中，海马抑制信号对适应性选择敏感，而海马增强与原始社会互动的后续记忆有关。这些发现强调了海马体在社会适应性学习中发挥着多方面的作用。