Center for Ecological Research, Kyoto University, Otsu, 520-2113 Shiga, Japan;
Department of Evolutionary Studies of Biosystems, Graduate University for Advanced Studies, Hayama, 240-0193 Kanagawa, Japan.
Proc Natl Acad Sci U S A. 2018 Feb 13;115(7):1541-1545. doi: 10.1073/pnas.1718884115. Epub 2018 Jan 29.
One of the core features of human speech is that words cause listeners to retrieve corresponding visual mental images. However, whether vocalizations similarly evoke mental images in animal communication systems is surprisingly unknown. Japanese tits () produce specific alarm calls when and only when encountering a predatory snake. Here, I show that simply hearing these calls causes tits to become more visually perceptive to objects resembling snakes. During playback of snake-specific alarm calls, tits approach a wooden stick being moved in a snake-like fashion. However, tits do not respond to the same stick when hearing other call types or if the stick's movement is dissimilar to that of a snake. Thus, before detecting a real snake, tits retrieve its visual image from snake-specific alarm calls and use this to search out snakes. This study provides evidence for a call-evoked visual search image in a nonhuman animal, offering a paradigm to explore the cognitive basis for animal vocal communication in the wild.
人类言语的核心特征之一是，单词会促使听众检索到相应的视觉心理图像。然而，令人惊讶的是，动物的交流系统中的发声是否也能类似地唤起心理图像，目前还不得而知。当日本大山雀遇到捕食性蛇时，它们只会发出特定的警报叫声。在这里，我表明，仅仅听到这些叫声就会使大山雀对类似蛇的物体变得更加具有视觉感知能力。在播放特定于蛇的警报叫声时，大山雀会接近以蛇形方式移动的木棍。然而，如果听到其他类型的叫声或木棍的移动方式与蛇的不同，它们就不会对同一根木棍做出反应。因此，在检测到真正的蛇之前，大山雀会从特定于蛇的警报叫声中检索到蛇的视觉图像，并利用该图像来搜索蛇。这项研究为非人类动物中的叫声唤起的视觉搜索图像提供了证据，为探索野生动物中动物发声交流的认知基础提供了范例。
