Шимпанзе и люди не единственные: ученые доказали, что гиббоны фокусируются на глазах

Researchers 研究者名 Makiko Uchikoshi 研究者名 Hattori, Yuko Overview Kyoto, Japan -- When you look at someone, you usually look at their face. It serves as one of the most important sources of social information in primates, so the evolution of face perception has attracted considerable scientific attention. While an abundance of this research has centered on humans and other great apes, very little has focused on gibbons. Gibbons were the earliest to diverge from the line leading to humans 17 million years ago, and they have developed a distinct social system characterized by small family groups and long-term pair bonding. They provide a particularly valuable model for investigating the relationship between social organization and the evolution of social cognition, motivating a team of researchers at Kyoto University to give gibbons the attention they deserve. "Understanding the evolutionary origins of the human mind requires comparative studies across the ape lineage," says first author Makiko Uchikoshi. "Despite their evolutionary importance, gibbons remain one of the least studied ape groups in cognitive research." The researchers used a voluntary, non-invasive eye-tracking method -- developed for previous studies -- to measure the eye movements of three adult male gibbons while they viewed photographs of both gibbon and human faces displayed on a screen. The experiment was conducted in the gibbons' regular living environment, allowing them to participate in or stop the session at their will at any time. Though the researchers were concerned about the effect that the equipment and the dimmed light would have on the subjects' comfort in their home, the gibbons soon began to sit in their designated place and wait while everything was set up. With the resulting data, the team examined how long the gibbons looked at the eyes, nose, mouth, and peripheral areas, and then compared the responses to gibbon and human faces. The results reveal that, when viewing both gibbon and human faces, gibbons spend more time looking at the eyes compared to other facial regions. Their gazes also linger on the eyes of their own species significantly longer than those of humans, indicating that gibbons share key patterns of visual attention with humans, great apes, and macaques, while also exhibiting a stronger focus on the eyes of members of their own species. The success of this eye-tracking approach expands opportunities for comparing species with markedly different social structures, and for understanding how social organization has shaped the evolution of social cognition across the primate lineage. These findings also provide new insights into the evolutionary foundations of face perception and social information processing in primates. "I have known the gibbons that participated in this study for nearly 28 years and have often experienced moments of eye contact, but I had never been able to measure objectively what they were actually looking at," says Uchikoshi. "Being able to quantify where they look and for how long felt almost like magic."