How does facial hair fit into the theory? With our brain entropy theory, facial hair would be a way to heat up a brain that has gotten too cool.
Women rarely have it. Women have smaller heads.
Men’s doesn’t start until puberty. And It doesn’t grow on the nose, cheeks, or forehead.
Men have bigger noses. This would allow for greater airflow, and more brain cooling.
So if women have smaller heads and noses, pressure may not have the capacity to get as low as it could in men. Low pressure would need heat. And one way the body can add heat is to add facial hair.
So what else happens of note during male puberty? The voice deepens. This is significant, because if high entropy meant fast, low entropy would be slow. And slow when it comes to sound is deep.
If men are designed to endure more stress. To endure stress, you must have room in your brain. We would call that a low entropy state. A low entropy state would cause a deeper voice and facial hair.