Meguerditchian Adrien, Vauclair Jacques
Department of Psychology, Research Center in Psychology of Cognition, Language and Emotion, Aix-Marseille University, 29, Av. Robert Schuman, 13621 Aix-en-Provence, France.
Brain Lang. 2009 Mar;108(3):167-74. doi: 10.1016/j.bandl.2008.10.004. Epub 2008 Dec 16.
Gestural communication is a modality considered in the literature as a candidate for determining the ancestral prerequisites of the emergence of human language. As reported in captive chimpanzees and human children, a study in captive baboons revealed that a communicative gesture elicits stronger degree of right-hand bias than non-communicative actions. It remains unclear if it is the communicative nature of this manual behavior which induces such patterns of handedness. In the present study, we have measured hand use for two uninvestigated behaviors in a group of captive olive baboons: (1) a non-communicative self-touching behavior ("muzzle wipe" serving as a control behavior), (2) another communicative gesture (a ritualized "food beg") different from the one previously studied in the literature (a species-specific threat gesture, namely "hand slap") in the same population of baboons. The hand preferences for the "food beg" gestures revealed a trend toward right-handedness and significantly correlated with the hand preferences previously reported in the hand slap gesture within the same baboons. By contrast, the hand preferences for the self-touching behaviors did not reveal any trend of manual bias at a group-level nor correlation with the hand preferences of any communicative gestures. These findings provide additional support to the hypothesized existence in baboons of a specific communicative system involved in the production of communicative gestures that may tend to a left-hemispheric dominance and that may differ from the system involved in purely motor functions. The hypothetical implications of these collective results are discussed within the theoretical framework about the origins of hemispheric specialization for human language.
手势交流是文献中被视为确定人类语言出现的祖先先决条件的一种方式。正如在圈养黑猩猩和人类儿童中所报道的那样，一项针对圈养狒狒的研究表明，一种交流手势比非交流动作引发更强程度的右手偏好。目前尚不清楚这种手部行为的交流性质是否会导致这种用手模式。在本研究中，我们测量了一组圈养橄榄狒狒中两种未被研究过的行为的用手情况：（1）一种非交流性的自我触摸行为（“擦嘴”作为对照行为），（2）另一种交流手势（一种仪式化的“乞食”），它与文献中先前研究的（一种特定物种的威胁手势，即“打手”）在同一狒狒群体中的手势不同。对“乞食”手势的用手偏好显示出右手偏好的趋势，并且与同一狒狒中先前报道的打手手势的用手偏好显著相关。相比之下，自我触摸行为的用手偏好在群体水平上没有显示出任何手部偏好的趋势，也与任何交流手势的用手偏好没有相关性。这些发现为狒狒中存在一个特定的交流系统提供了额外支持，该系统参与交流手势的产生，可能倾向于左半球优势，并且可能与参与纯运动功能的系统不同。这些总体结果的假设性影响在关于人类语言半球特化起源的理论框架内进行了讨论。
