Although unable to see colors, blind people are able to understand them. For example knowing intuitively that two bananas are likely to have the same color. Explanations.
- Contrary to what we thought so far, blind people are able to “understand” the colors of objects and animals based on their knowledge of them.
- This understanding of colors is not the result of memorization, but can instead be generalized to new examples.
How to explain that blind people can instinctively know that tomatoes are all red, that the color of bananas is yellow and that a rainy sky does not have the same hue as a sunny sky? This is because, although unable to distinguish colors, they instinctively understand their meaning.
This is highlighted by a new study published by researchers at Johns Hopkins University in the United States. Published in the journal Proceedings of the National Academy of Sciences (PNAS)she challenges the belief that people born blind could never truly understand color by demonstrating that congenitally blind people and sighted people do in fact understand it in very similar ways.
“A common intuition going back to Locke is that a blind person might learn the arbitrary fact that marigolds are ‘yellow’ and tomatoes are ‘red’, but still would not understand color in depth, develops Marina Bedny, lead author. The idea is that to really know something, you have to see it for yourself, and that without vision, you learn superficial facts by talking to people. This study of blind people suggests otherwise. Talking to people conveys a deep understanding of color better than arbitrary facts about color.”
An instinctive understanding
To reach this conclusion, the researchers conducted a two-phase experiment with blind and sighted adults. First, they were asked about the common color of objects (the arbitrary facts), why they were that color, and the probability that two of those randomly chosen objects were the same color. The objects were a combination of natural objects like fruits, plants and precious stones, and manufactured objects (pen, banknote, road sign).
Although blind participants did not always agree with sighted participants on arbitrary facts about color (for example that bananas are yellow), the researchers found that blind people’s reasoning about why bananas are yellow, and their judgments about the probability of two bananas being the same color (color consistency) were identical to those of the sighted people. This result applies to different types of objects, including those that are colored for specific reasons, such as stop signs, coins, and even wedding dresses.
Divergence on the color of polar bears
Interestingly, the blind also demonstrated the same degree of understanding as the sighted in explaining why objects had certain colors. This is the case of the color of polar bears. While all sighted people said they were white to blend in with the snow, a large number of blind participants felt they were black to absorb heat and stay warm. “Blind people give a consistent explanation of a polar bear’s color even if they disagree with sighted people about a polar bear’s particular color”notes Judy Kim, co-author.
This understanding of colors by blind people was confirmed by the second part of the experiment, when the team asked the participants to make predictions about the colors of imaginary objects that they had never seen or which they had never heard of in an “explorer on an island” scenario. “We wanted to see how people reason about things they’ve never experienced. It’s a great way to test the depth of people’s understanding of color.”says Dr. Kim.
Once again the blind and the sighted made identical judgments about these new objects. This shows that their knowledge of colors generalizes to new examples and does not depend on memorization.
Understand the brain springs of color understanding
In a recent related study, the same team even found that while blind people have never been able to see animals like elephants and lions, they make educated guesses about their appearance based on their understanding of the why animals look the way they do (for example, mammals that live on land have legs).
Researchers now want to understand how this knowledge of colors is managed by the brain, and how blind people acquire color understanding. “We assume this is casual learning through talking and reading, but when exactly does this happen? Do blind and sighted children learn this information in the same way? Exists Are there developmental differences where sighted children acquire this information at an earlier age, before using language, and blind children acquire it only after they learn to speak and then catch up? “. These are all questions that future work will answer.
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