Scheider Linda, Waller Bridget M, Oña Leonardo, Burrows Anne M, Liebal Katja
Dept. of Education and Psychology, Freie Universität Berlin, Berlin, Germany.
Dept. of Psychology, University of Portsmouth, Portsmouth, United Kingdom.
PLoS One. 2016 Mar 15;11(3):e0151733. doi: 10.1371/journal.pone.0151733. eCollection 2016.
Non-human primates use various communicative means in interactions with others. While primate gestures are commonly considered to be intentionally and flexibly used signals, facial expressions are often referred to as inflexible, automatic expressions of affective internal states. To explore whether and how non-human primates use facial expressions in specific communicative interactions, we studied five species of small apes (gibbons) by employing a newly established Facial Action Coding System for hylobatid species (GibbonFACS). We found that, despite individuals often being in close proximity to each other, in social (as opposed to non-social contexts) the duration of facial expressions was significantly longer when gibbons were facing another individual compared to non-facing situations. Social contexts included grooming, agonistic interactions and play, whereas non-social contexts included resting and self-grooming. Additionally, gibbons used facial expressions while facing another individual more often in social contexts than non-social contexts where facial expressions were produced regardless of the attentional state of the partner. Also, facial expressions were more likely 'responded to' by the partner's facial expressions when facing another individual than non-facing. Taken together, our results indicate that gibbons use their facial expressions differentially depending on the social context and are able to use them in a directed way in communicative interactions with other conspecifics.
非人灵长类动物在与其他个体互动时会使用各种交流方式。虽然灵长类动物的手势通常被认为是有意且灵活使用的信号，但面部表情往往被视为情感内在状态的不灵活、自动的表达。为了探究非人灵长类动物是否以及如何在特定的交流互动中使用面部表情，我们通过采用新建立的长臂猿面部动作编码系统（GibbonFACS）对五种小型猿类（长臂猿）进行了研究。我们发现，尽管个体之间通常距离很近，但在社交情境（与非社交情境相对）中，与非面对面的情况相比，长臂猿面对另一个个体时面部表情的持续时间明显更长。社交情境包括梳理毛发、争斗互动和玩耍，而非社交情境包括休息和自我梳理毛发。此外，与非社交情境相比，长臂猿在社交情境中面对另一个个体时更频繁地使用面部表情，在非社交情境中，无论对方的注意力状态如何都会产生面部表情。而且，与非面对面时相比，长臂猿在面对另一个个体时，其面部表情更有可能引发对方的面部表情“回应”。综上所述，我们的研究结果表明，长臂猿会根据社交情境不同地使用面部表情，并且能够在与其他同种个体的交流互动中以有针对性的方式使用面部表情。
