Domestication Lab, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria.
Department of Behavioral & Cognitive Biology, University of Vienna, Vienna, Austria.
PeerJ. 2023 Jul 6;11:e15601. doi: 10.7717/peerj.15601. eCollection 2023.
Most studies on dogs' cognitive skills in understanding human communication have been conducted on pet dogs, making them a role model for the species. However, pet dogs are just a minor and particular sample of the total dog world population, which would instead be better represented by free-ranging dogs. Since free-ranging dogs are still facing the selective forces of the domestication process, they indeed represent an important study subject to investigate the effect that such a process has had on dogs' behavior and cognition. Despite only a few studies on free-ranging dogs (specifically village dogs) having been conducted so far, the results are intriguing. In fact, village dogs seem to place a high value on social contact with humans and understand some aspects of humans' communication. In this study we aimed to investigate village dogs' ability in understanding a subtle human communicative cue: human facial expressions, and compared them with pet dogs, who have already provided evidence of this social skill. We tested whether subjects were able to distinguish between neutral, happy, and angry human facial expressions in a test mimicking a potential real-life situation, where the experimenter repeatedly performed one facial expression while eating some food, and ultimately dropped it on the ground. We found evidence that village dogs, as well as pet dogs, could distinguish between subtle human communicative cues, since they performed a higher frequency of aversive gazes (looking away) in the angry condition than in the happy condition. However, we did not find other behavioral effects of the different conditions, likely due to the low intensity of the emotional expression performed. We suggest that village dogs' ability in distinguishing between human facial expressions could provide them with an advantage in surviving in a human-dominated environment.
大多数关于狗理解人类交流的认知技能的研究都是在宠物狗身上进行的,这使它们成为该物种的榜样。然而,宠物狗只是狗类总体种群中的一个次要且特殊的样本,而自由放养的狗则更能代表整个种群。由于自由放养的狗仍在面临着驯化过程的选择压力,因此它们确实是一个重要的研究对象,可以研究这种过程对狗的行为和认知产生的影响。尽管迄今为止对自由放养的狗(特别是村庄狗)进行的研究很少,但结果却很有趣。事实上,村庄狗似乎非常重视与人类的社交接触,并且能够理解人类交流的某些方面。在这项研究中,我们旨在研究村庄狗理解微妙的人类交流线索的能力:人类面部表情,并将其与已经证明具有这种社交技能的宠物狗进行比较。我们测试了在模仿潜在的现实生活情境的测试中,狗是否能够区分中性、高兴和生气的人类面部表情,在这种情境中,实验者反复做出一种面部表情,同时吃一些食物,最终将食物扔在地上。我们发现有证据表明,村庄狗和宠物狗都能够区分微妙的人类交流线索,因为它们在生气的情况下比在高兴的情况下更频繁地做出厌恶的眼神(移开视线)。但是,我们没有发现其他条件的行为影响,可能是由于所表现出的情绪表达强度较低所致。我们认为,村庄狗区分人类面部表情的能力可能使它们在人类主导的环境中生存具有优势。