Data from: Vocal turn-taking in a nonhuman primate is learned during ontogeny

Conversational turn-taking is an integral part of language development, as it reflects a confluence of social factors that mitigate communication. Humans coordinate the timing of speech based on the behaviour of another speaker, a behaviour that is learned during infancy. While adults in several primate species engage in vocal turn-taking, the degree to which similar learning processes underlie its development in these non-human species or are unique to language is not clear. We recorded the natural vocal interactions of common marmosets (Callithrix jacchus) occurring with both their sibling twins and parents over the first year of life and observed at least two parallels with language development. First, marmoset turn-taking is a learned vocal behaviour. Second, marmoset parents potentially played a direct role in guiding the development of turn-taking by providing feedback to their offspring when errors occurred during vocal interactions similarly to what has been observed in humans. Though species-differences are also evident, these findings suggest that similar learning mechanisms may be implemented in the ontogeny of vocal turn-taking across our Order, a finding that has important implications for our understanding of language evolution.

会话轮流发言（conversational turn-taking）是语言发展不可或缺的组成部分，其体现了多种社会因素的协同作用，助力有效交流。人类会根据其他说话者的行为调整自身的发言时机，这类行为在婴儿时期便已习得。尽管多个灵长类物种的成年个体均存在发声轮流行为（vocal turn-taking），但目前尚不清楚，这类行为的发育在多大程度上受类似的学习过程支配，又或是仅为人类语言所独有。我们记录了普通狨猴（Callithrix jacchus）在出生后第一年与双胞胎兄弟姐妹及双亲之间的自然发声互动，并观察到其与人类语言发展至少存在两处相似之处：其一，狨猴的发声轮流行为属于后天习得的发声行为；其二，狨猴双亲可能在引导轮流行为发育中发挥了直接作用，当幼崽在发声互动中出现失误时，它们会像人类育儿行为中观察到的那样，为幼崽提供反馈。尽管物种间的差异同样显著，但这些发现表明，在灵长目动物中，发声轮流行为的个体发育（ontogeny）可能受到类似的学习机制支配，这一发现对于我们理解语言演化具有重要意义。