It is said that this is a scientific phenomenon. At that time, the brain nerve stimulated the cortex, and the nerve conduction hair surface produced this phenomenon.
I don't know if you have found out, as early as in the distant ancient times, Yue Fei wrote a poem that was full of anger. Needless to say, the original meaning of the word "anger rushing to the crown" has always been regarded as an exaggerated word, but it is real in real life. When we are cold, or extremely scared and angry, our human hair, including hair, may stand upright. There are different opinions about this, some are explained by evolution, and some are explained by science.
1. Scientific explanation: This is a stress reaction. When people feel scared and angry, they release a lot of adrenaline. This hormone can enhance the sensitivity of carriers. There is a special muscle near human hair, which is responsible for receiving adrenaline and exciting the muscle, so as to achieve the hair or hair we see visually. Everyone has experienced this phenomenon, just like when the weather is cold, the skin will unconsciously produce goose bumps in addition to feeling cold. That's because our skin can not only protect our internal organs, realize the function of material exchange, but also regulate the temperature. When we feel cold or our mood reaches its peak, a muscle under our hair will also contract, thus achieving an upright effect. The purpose is to make the skin surface firmer and harder, form a protective wall and protect our bodies.
Second, folklore these remarks seem to be not so reliable, but careful study seems to have some truth. There is a saying that in ancient times, we were still in the form of apes and lived and multiplied in trees. At that time, when we were frightened, our hair stood up to make our bodies look stronger, thus overwhelming each other from the momentum. This truth is the same as the cat-dog fight we see now. Another way of saying it is that in the process of natural evolution, people will have psychological fear in order to avoid danger, just as we will feel pain and then consciously avoid what causes it.
Some problems are common in our life, but we have never thought about them carefully. Just like the topic mentioned today, we only know that in real life, when we are scared by cold or fear, our hair will stand upright. We only think it is a natural phenomenon and never delve into its meaning. In fact, even with scientific proof, we are more willing to believe in a more dramatic theory of evolution.