In all countries where we use different words to say "blue" and "green", most people can see the difference easily, but if your language has only one word for "blue and green"(I think it is true for instance in Thai), people are much less expert at distinguishing the gradients of blue to green even within the people with "normal" vision. Here is how I see this.
FIRST we are born each with a different perception. We say normal and color blind to have broad categories, but everyone has a different perception. It is like we distinguish between black and white people but we know that it covers a lot of variations in skin tone. SECOND, we acquire an education, a language that will make a difference in the way our brain interprets the colors, no matter if we are color blind or not. THIRD To a certain extent, we can adjust our perception by re-interpreting the colors, as many people testify here. They use colored glass or memory tips, or they reinterpret the world as Gordon (up here) has suggested. FINALLY, memory plays a big role. Most people with "normal"vision have little memory of colors,they just vaguely remember it was green for instance. By contrast, some rare people can get to a store and find the exact same shade of an emerald cloth they bought a year ago.
So, not two people see the exact same thing anyway. We do the best with what we got.
culture and memory play a role too
In all countries where we use different words to say "blue" and "green", most people can see the difference easily, but if your language has only one word for "blue and green"(I think it is true for instance in Thai), people are much less expert at distinguishing the gradients of blue to green even within the people with "normal" vision. Here is how I see this.
FIRST we are born each with a different perception. We say normal and color blind to have broad categories, but everyone has a different perception. It is like we distinguish between black and white people but we know that it covers a lot of variations in skin tone. SECOND, we acquire an education, a language that will make a difference in the way our brain interprets the colors, no matter if we are color blind or not. THIRD To a certain extent, we can adjust our perception by re-interpreting the colors, as many people testify here. They use colored glass or memory tips, or they reinterpret the world as Gordon (up here) has suggested. FINALLY, memory plays a big role. Most people with "normal"vision have little memory of colors,they just vaguely remember it was green for instance. By contrast, some rare people can get to a store and find the exact same shade of an emerald cloth they bought a year ago.
So, not two people see the exact same thing anyway. We do the best with what we got.