Intentional signalling plays a fundamental role in human communication. Mapping the taxonomic distribution of comparable capacities may thus shed light on the selective pressures that enabled the evolution of human communication. Nonetheless, severe methodological issues undermine comparisons among studies, species and communicative modalities. Here, we discuss three main obstacles that hinder comparative research of 'first-order' intentional signalling (i.e. voluntary signalling in pursuit of a cognitively represented goal): (i) inconsistency in how behavioural hallmarks are defined and operationalised, (ii) testing of behavioural hallmarks without statistical comparison to control conditions, and (iii) bias against the publication of negative results. To address these obstacles, we present a four-step scheme with 20 statistical operational criteria to distinguish between non-intentional and first-order intentional signalling. Our unified scheme applies to visual and audible signals, thereby validating comparison across communicative modalities and species. This, in turn, promotes the generation and testing of hypotheses about the evolution of intentional communication.

中文翻译：

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意向沟通：解决分配一阶意向信号的方法论问题

意向性信号在人类交流中起着重要作用。因此，绘制可比能力的分类分布图可能有助于揭示促成人类交流进化的选择压力。尽管如此，严重的方法论问题破坏了研究、物种和交流方式之间的比较。在这里，我们讨论了阻碍“一阶”有意信号（即追求认知表征目标的自愿信号）比较研究的三个主要障碍：（i）行为标志的定义和操作方式不一致，（ii）测试没有与对照条件进行统计比较的行为特征，以及 (iii) 对负面结果发表的偏见。为了解决这些障碍，我们提出了一个包含 20 个统计操作标准的四步方案，以区分非故意和一阶故意信号。我们的统一方案适用于视觉和听觉信号，从而验证交流方式和物种之间的比较。这反过来又促进了有关有意交流演变的假设的产生和检验。