Stomp Mathilde, Leroux Maël, Cellier Marjorie, Henry Séverine, Hausberger Martine, Lemasson Alban
CNRS, EthoS (Éthologie animale et humaine), Univ Rennes, Normandie Univ, UMR 6552, F-35380, Paimpont, France.
Naturwissenschaften. 2018 Sep 12;105(9-10):57. doi: 10.1007/s00114-018-1582-9.
While the vocal coding of human and animal internal states has been widely studied, the possible acoustic expression of "positive" emotions remains poorly known. Recent studies suggest that snorts (non-vocal sounds produced by the air expiration through the nostrils) appear to be reliable indicators of positive internal states in several ungulate species. Here, we hypothesised in horses that the acoustic structure of the snort could vary with the subjects' current emotional state. Indeed, a preliminary sound analysis of snorts let us suggest structure variations related to the presence of pulsations. We recorded snorts from 20 horses living in a riding center. Auditory playbacks run with 20 humans first confirmed the existence of two snort subtypes, i.e. one pulsed and one non-pulsed. Observations were then conducted to compare the distribution of these two subtypes according to the location (stall/pasture) of the signaller as a contextual determinant of its internal state and to its ears' position as a reflection of its emotional state. We found that both subtypes were preferentially observed in positive contexts, but that pulsed snorts were even more associated with highly appreciated situations (in pasture and with ears forward). This study is a step further in the identification of indicators of positive emotions in horses and more generally in the understanding of the acoustic emotions' coding.
虽然人类和动物内部状态的发声编码已得到广泛研究，但“积极”情绪可能的声学表达仍鲜为人知。最近的研究表明，喷鼻声（通过鼻孔呼气产生的非发声声音）似乎是几种有蹄类动物积极内部状态的可靠指标。在此，我们假设在马中，喷鼻声的声学结构可能会随个体当前的情绪状态而变化。事实上，对喷鼻声的初步声音分析让我们推测其结构变化与脉动的存在有关。我们记录了来自一个马术中心的20匹马的喷鼻声。首先让20名人类进行听觉回放，证实了存在两种喷鼻声亚型，即一种有脉动的和一种无脉动的。然后进行观察，以根据信号发出者的位置（马厩/牧场）作为其内部状态的情境决定因素，以及根据其耳朵位置作为其情绪状态的反映，来比较这两种亚型的分布情况。我们发现，两种亚型在积极情境中都更常被观察到，但有脉动的喷鼻声与高度愉悦的情况（在牧场且耳朵向前）甚至更相关。这项研究在识别马的积极情绪指标方面又迈进了一步，更广泛地说，在理解声学情绪编码方面也是如此。
