Conversation between two people involves subtle nonverbal coordination in addition to speech. However, the precise parameters and timing of this coordination remain unclear, which limits our ability to theorize about the neural and cognitive mechanisms of social coordination. In particular, it is unclear if conversation is dominated by synchronization (with no time lag), rapid and reactive mimicry (with lags under 1 s) or traditionally observed mimicry (with several seconds lag), each of which demands a different neural mechanism. Here we describe data from high-resolution motion capture of the head movements of pairs of participants (n = 31 dyads) engaged in structured conversations. In a pre-registered analysis pathway, we calculated the wavelet coherence of head motion within dyads as a measure of their nonverbal coordination and report two novel results. First, low-frequency coherence (0.2–1.1 Hz) is consistent with traditional observations of mimicry, and modeling shows this behavior is generated by a mechanism with a constant 600 ms lag between leader and follower. This is in line with rapid reactive (rather than predictive or memory-driven) models of mimicry behavior, and could be implemented in mirror neuron systems. Second, we find an unexpected pattern of lower-than-chance coherence between participants, or hypo-coherence, at high frequencies (2.6–6.5 Hz). Exploratory analyses show that this systematic decoupling is driven by fast nodding from the listening member of the dyad, and may be a newly identified social signal. These results provide a step towards the quantification of real-world human behavior in high resolution and provide new insights into the mechanisms of social coordination.

中文翻译：

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你在我的波长上吗？二进位对话中的人际协调

两个人之间的对话除了言语外还涉及微妙的非语言协调。但是，这种协调的确切参数和时间安排尚不清楚，这限制了我们对社会协调的神经和认知机制进行理论化的能力。尤其是，尚不清楚对话是由同步（无时间滞后），快速反应性模仿（滞后1秒以下）还是传统观察到的模仿（滞后几秒钟）主导，而每种模仿都需要不同的神经机制。在这里，我们描述了来自参与者对头部运动的高分辨率运动捕捉的数据（n = 31 dyad）进行结构化对话。在预先注册的分析路径中，我们计算了二元组中头部运动的小波相干性，以衡量其非语言协调性，并报告了两个新颖的结果。首先，低频相干性（0.2–1.1 Hz）与传统的模仿观察相符，并且建模表明，这种行为是由一种机制引起的，这种机制在引导者和跟随者之间保持600毫秒的恒定滞后。这与模仿行为的快速反应（而不是预测或记忆驱动）模型相符，并且可以在镜像神经元系统中实现。其次，我们发现在高频（2.6–6.5 Hz）时，参与者之间的相干性低于预期或低相干性的意外模式。探索性分析表明，这种系统性的脱钩是由来自听代成员的快速点头驱动的，并且可能是新发现的社交信号。这些结果为高分辨率量化现实世界中的人类行为迈出了一步，并为社会协调机制提供了新见解。