Department of Psychology-King Henry Building, University of Portsmouth, King Henry I Street, Portsmouth, PO1 2DY, UK.
University of the Sacred Heart, Shibuya, Tokyo, Japan.
Learn Behav. 2023 Mar;51(1):15-33. doi: 10.3758/s13420-022-00553-1. Epub 2022 Nov 28.
We investigated the communicative gestures used by chimpanzee and human infants. In contrast to previous studies, we compared the species at the same age (12-14 months) and used multiple groups living in diverse socioecological settings for both species. We recorded gestures produced by infants and those produce by others and directed toward infants. We classified the gestures into the following types: human-usual, chimpanzee-usual, and species-common; and searched for within species and between species differences. We found no significant differences between groups or species in overall rates of infant-produced or infant-received gestures, suggesting that all of these infants produced and received gestures at similar levels. We did find significant differences, however, when we considered the three types of gesture. Chimpanzee infants produced significantly higher rates of chimpanzee-usual gestures, and human infants produced significantly higher rates of human-usual gestures, but there was no significant species difference in the species-common gestures. Reports of species differences in gesturing in young infants, therefore, could be influenced by investigators' choice of gesture type. Interestingly, we found that 1-year-old infants produced the gesture of "hold mutual gaze" and that the chimpanzee infants had a significantly higher rate than the human infants. We did not find strong evidence that the specific types of gestural environment experienced by young infants influenced the types of gestures that infants produce. We suggest that at this point in development (before human infants use lots of speech), nonverbal communicative gestures may be equally important for human and chimpanzee infants.
我们研究了黑猩猩和人类婴儿使用的交际手势。与之前的研究不同，我们在相同的年龄（12-14 个月）比较了这两个物种，并使用了多个生活在不同社会生态环境中的物种。我们记录了婴儿自己做出的手势以及他人指向婴儿做出的手势。我们将这些手势分为以下几类：人类常用手势、黑猩猩常用手势和物种共有手势；并寻找了种内和种间的差异。我们发现，在婴儿自身产生或接受的手势的总体比率方面，各组或各物种之间没有显著差异，这表明所有这些婴儿以相似的水平产生和接受手势。然而，当我们考虑到这三种手势类型时，我们确实发现了显著的差异。黑猩猩婴儿产生的黑猩猩常用手势的比率明显较高，而人类婴儿产生的人类常用手势的比率明显较高，但物种共有手势在两个物种之间没有显著差异。因此，关于幼儿在手势方面的物种差异的报告可能受到研究人员对手势类型选择的影响。有趣的是，我们发现 1 岁婴儿会做出“保持相互注视”的手势，而且黑猩猩婴儿比人类婴儿做出这种手势的比率更高。我们没有发现强有力的证据表明，幼儿经历的特定类型的手势环境会影响婴儿产生的手势类型。我们认为，在这个发展阶段（在人类婴儿使用大量言语之前），非言语交际手势可能对人类和黑猩猩婴儿同样重要。
