Anyone with normal vision will agree that blood is red, the same color as strawberries or the planet Mars. But could it be that what we call "red" is for another, for example, "blue"? More recently, any scientist would have answered you that people with normal vision see all colors the same way.
How do we see colors? The brain processes light that hits the cells of the eyes, and our perception of the color of this light is associated with a universal emotional response. But recent experiments have shown that perhaps we all perceive colors differently.
In other words, for you, blood is the color that the other person would call blue, and your blue sky for someone else would be red. But our individual perception will not affect what emotions the color of blood or sky will cause.
This phenomenon has been demonstrated in experiments on squirrel monkeys, which, like color blind people and most mammals, have two types of cones: those that are sensitive to green and those that are sensitive to blue. That is, to them the red and green light wavelengths look neutral and they cannot see the red and green dots on a gray background.
Squirrel Monkey: Scientists at the University of Washington injected the monkeys with a virus that allowed them to see red as well as green and yellow. After that, the monkeys were able to perceive new information, despite the fact that their brains are not genetically programmed to perceive red signals.
Studies in monkeys back in 2009 showed that the perception of light wavelengths is not predetermined. All of this led scientists to believe that color is a personal experience. When we are born, our neurons do not respond to color in a specific way and we develop a unique perception of color.
However, even though we see colors differently, our emotional responses to the same colors are universal. Regardless of what you see when looking at a clear sky, it is the short wavelengths of light, which we call "blue", that have a calming effect on us, while the long ones, that is, yellow, orange and red, stimulate us. As the scientists explain, our reaction to colors was created so that all living organisms determine the cycles of day and night. So the dominance of blue at night explains why we feel the most tired at this time, and the dominance of yellow light in the morning is exactly what makes us wake up.