Department of Psychobiology, Faculty of Psychology, Universitat de València, Valencia, Spain.
Center of Network Biomedical Investigation - Mental Health (CIBERSAM), Madrid, Spain.
PLoS One. 2021 May 6;16(5):e0251083. doi: 10.1371/journal.pone.0251083. eCollection 2021.
At a time of growing interest in and awareness about the relationships between humans and animals, it is of relevance to scientifically analyse the intrinsic nature of these interactions. Reactions to emotional tears show our extraordinary capacity for detecting micro-nuances when judging another human's face. Regarding such behaviour, previous studies carried out in our laboratory have pointed to an adaptive function of emotional tears: i.e. their inhibitory influence on perceived aggressiveness. In the present work we aimed to further explore that hypothesis by extending our investigation from humans to animals, using pictures of five different animal faces (cat, dog, horse, chimpanzee, hamster) to which tears were added digitally. To this end, we conducted an online study of 403 participants recruited from different social networks and academic institutions. We questioned the participants about their perceptions of emotional intensity, aggressiveness and friendliness in the animal faces and analysed the comparisons they made between faces with and without tears. In addition, a latent variable referred to as "passion for animals" was measured using different indicators. By adding the results obtained in each species and breaking them down into different basic emotions, we found that the presence of tears was related to a higher absolute frequency of participants who perceived sadness, which endorsed our previous results obtained using images of humans. Regarding aggressiveness, the presence of tears favoured the perception of less aggressiveness. A structural equation model was also conducted to explore the relations among all the measured variables. The model confirmed that the presence of tears in the animal faces had a significant influence on the perception of higher emotional intensity and friendliness, and of lower aggressiveness.
在人们对人类与动物之间的关系越来越感兴趣并提高认识的时代，从科学角度分析这些相互作用的内在本质具有重要意义。对情绪眼泪的反应显示了我们在判断他人面部表情时检测细微差异的非凡能力。关于这种行为，我们实验室之前的研究已经指出情绪眼泪具有适应功能：即它们对感知到的攻击性的抑制影响。在目前的工作中，我们旨在通过将研究从人类扩展到动物来进一步探索这一假设，使用添加了数字眼泪的五种不同动物面孔（猫、狗、马、黑猩猩、仓鼠）的图片。为此，我们对来自不同社交网络和学术机构的 403 名参与者进行了在线研究。我们询问了参与者对动物面孔的情绪强度、攻击性和友好性的感知，并分析了他们在有泪和无泪面孔之间的比较。此外，还使用不同的指标测量了一个称为“对动物的热情”的潜在变量。通过汇总每种物种的结果并将其分解为不同的基本情绪，我们发现眼泪的存在与更多参与者感知到悲伤的绝对频率有关，这证实了我们之前使用人类图像获得的结果。关于攻击性，眼泪的存在有利于感知到较低的攻击性。还进行了结构方程模型来探索所有测量变量之间的关系。该模型证实，动物面孔中的眼泪存在对感知更高的情绪强度、友好性和更低的攻击性有显著影响。
