The evolutionary secrets leaked from the "window of human soul" ---- Novels for me geiwo8.com

The eyes, known as the "windows of the soul," hide immense secrets. Scientists have discovered that among primates, the whites of our eyes are a unique feature to us, playing a crucial role in our evolutionary process.

Scientists say that the white sclera (the tissue surrounding the iris) expands our field of vision, allowing us to monitor others' gazes and meet their eyes across a crowded room; it also enables us to glare at enemies, making our eyes tools for expressing emotions.

In contrast, apes have dark scleras, which make it difficult for other animals to track their gaze or guess what they're looking at.

Professor Robin Dunbar of the University of Liverpool's Evolutionary Psychology department says: "Our eye whites are extremely important. They allow our eyes not only to see but also to signal. For instance, we can study others' gazes to determine if they're lying or joking."

He continues: "In other words, we use our eyes to reflect our inner world. Apes cannot do this."

Hiroshi Kobayashi and Shiro Kohshima of the Tokyo Institute of Technology compared human eyes with those of 81 other primate species. Their article published in the Journal of Human Evolution states that only humans possess scleras lighter than the color of our faces and other parts of our bodies: this key anatomical feature enhances the power of human gazes. In contrast, all other primates conceal their gazes. They have dark scleras, making it difficult to determine the edges of their scleras and thus hard to guess their line of sight. As these two researchers put it, this conclusion "reflects a clear difference between humans and other primates in using gaze signals for communication."

In the past, many scientists believed that the difference between human eyes and those of apes arose because the latter developed dark scleras during evolution to protect themselves from glaring sunlight. However, as Kobayashi and Kohshima found, nocturnal primates also have dark eyes.

They believe that apes conceal their gaze to mislead predators into thinking they've been spotted, thereby preventing the predators from wasting time trying to approach them.

However, humans have abandoned this protective structure because our eyes have a unique social function. Professor Chris Stringer of the Natural History Museum says: "Our eye whites enhance our ability to communicate silently."

He adds: "It's unclear whether this is related to aggressive males attempting to subdue others through staring contests, or if it involves some kind of sexual signal or something else. But it's clearly very important to us humans."

Researchers have already noticed this difference between apes and humans: they observed that apes try to avoid making eye contact with other members of their group. Staring at chimpanzees can sometimes provoke them to attack. Humans, on the other hand, often look each other in the eye.

For example, we frequently make eye contact when talking. When we listen to someone speak, we often look at their eyes. Conversely, the speaker usually looks elsewhere, occasionally making eye contact with the audience: first to check if they're listening; finally sending a silent signal indicating they're about to finish.

Dunbar also says: "Looking at someone's eyes while they're speaking is very important. If we don't make eye contact, we won't be able to correctly judge what they're saying. If we can't see the speaker's eyes, the listeners become restless. Are they joking, being insincere, sarcastic, or deliberately provocative? We need visual cues to judge the true meaning of words."

He concludes: "Apes or monkeys aren't like this. They may understand an opponent's actions, but only humans can judge what another person is thinking. Our eye whites are crucial in helping us evaluate this mental state. As someone once said, don't trust a person who can't look you in the eye."