Eye Whites: A Big Human Advantage

Questions Answered: Why do babies need naps? Why do Chinese people have folds over their eyes? What is the evolutionary purpose of the whites of our eyes? Why do we squint?

Do the eyes cool the brain? If they did, it would explain everything. The smaller brain that would tend to overheat, would have an extra heat sink. The larger brain, prone get too cool, would have a smaller cooling mechanism.

Are Asian eyes smaller? Not exactly. Their optic discs are larger. But they have a fold on their eyelid, which, to me, would lower the surface area on the outside air and cooling function if the eyes. How would our theory explain the purpose of this fold? Because they have larger brains, they have potential for lower entropy. Since their eyes cannot change size, their bodies do what they can to adapt.

Babies have this fold. Babies have the biggest head in proportion to their bodies. And coincidentally, birds lose a similar fold when exposed to 24-hour light for a long enough period.

Yes, the eyes cool the brain. But not even on the same order of magnitude of sleep. The purpose of the whites of the eyes is literally to cool [which explains the color]. The magnitude of this cooling is on par with the stress of the light in the first place. So the net effect of the stress+cooling is the important part. If the brain is large and cool, smaller eyes trend the brain entropy positive. If the brain is small and hot, the net effect of the eyes would be negative.

Squints do not change the pupils. They block out the whites of the eyes. And the pupils do change to adapt to changing light as well. Pupil dilation does not change the surface area of the eye.

So why would you squint when you walk outside? Well, if the temperature outside is warmer than your body, a squint would actually cool your brain. The lower the surface area on the hotter outdoor air, the cooler your brain can get.

If it’s cold, a squint would do the opposite. My minimizing surface area exposed to the cold air, the eye adapts by doing what it can to warm the brain: squints.

Humans are the only among 633 species of primates with eye whites. What is our advantage over the animal kingdom? Thought. The eye whites or sclera allows humans to think more and faster than any other being on the planet. 

Why do babies need naps? And why does that nap schedule evolve?Their heads are growing, but their eye size stays fixed. They have big heads relative to their bodies, and big eyes relative to their heads. But their heads are still small in comparison to everyone else. Meaning less total stress can accumulate before a nap. But bigger eyes (relative to head size) allow the brain to operate at a higher energy level. Noses are smallest, so it is essential that the eyes are biggest.

Therefore, the purpose of the whites of your eyes is to cool your brain. The eye is a beautiful and perfect equilibrium device, giving humans a distinct thought advantage over the rest of the animal kingdom.


  1. https://www.google.com/amp/s/www.chicagotribune.com/news/ct-xpm-1985-10-13-8503100141-story,amp.html
  2. https://www.ncbi.nlm.nih.gov/m/pubmed/12665226/
  3. https://www.techtimes.com/articles/95875/20151015/why-humans-weird-eyes.htm

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