For human infants, producing recognizable speech is more than a cognitive process. It is a motor skill that requires infants to learn to coordinate multiple muscles of varying functions across their body. This coordination is directly linked to ongoing fluctuations in heart rate; a physiological process that can scaffold behavior. We investigated whether ongoing fluctuations in heart rate coincide with vocal production and word formation in 24-mo-old infants. Infants were most likely to produce a vocalization when heart rate fluctuations reached a peak (local maximum) or trough (local minimum). Vocalizations produced at the peak were longer than expected by chance. Functionally, vocalizations produced just before the trough, while heart rate is decelerating, were more likely to be recognized as a word by naive listeners. Thus, for the developing infant, heart rate fluctuations align with the timing of vocal productions and are associated with their duration and the likelihood of producing recognizable speech. Our results have broad and immediate implications for understanding normative language development, the evolutionary basis and physiological process of vocal production, and potential early indicators of speech and communication disorders.

中文翻译：

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婴儿发声的可识别性和时间与心率的波动有关


对于人类婴儿来说，产生可识别的语音不仅仅是一个认知过程。这是一项运动技能，需要婴儿学会协调身体中不同功能的多块肌肉。这种协调与心率的持续波动直接相关;一个可以支撑行为的生理过程。我们调查了 24 个月大婴儿心率的持续波动是否与发声和构词一致。当心率波动达到峰值 （局部最大值） 或低谷 （局部最小值） 时，婴儿最有可能发出发声。在高峰期产生的发声时间比偶然预期的要长。从功能上讲，在低谷之前产生的发声，当心率减速时，更有可能被天真的听众识别为一个词。因此，对于发育中的婴儿，心率波动与发声的时间一致，并与发声的持续时间和产生可识别语音的可能性有关。我们的结果对于理解规范语言发展、发声产生的进化基础和生理过程以及言语和沟通障碍的潜在早期指标具有广泛而直接的意义。