Second-year Psychology students participating in the University Honours College follow a workshop on Blogging Science, in which they learn to communicate science to the general public by means of informing, giving an opinion, and relating science to issues in society. A selection of these blog posts is published on Mindwise. Today’s post is by Diana Wagner.


 

Imagine that you look outside of your window and see a beautiful sunset. You will probably think about how wonderfully red the sunset is, and what other beautiful colours you can see. That is also something that anyone with normal colour vision would probably do as well. They might agree that the sunset shines in reddish colours, and they could also potentially compare that colour to the colour of strawberries and roses. That is because all of these objects are red.

Could it be, however, that the colour you perceive as ‘red’ is someone else’s ‘magenta’ – or even an entirely different colour? Could people have colour perceptions and representations that are different compared to others? These are questions a lot of people, including philosophers and neuroscientists, have asked themselves for decades.

 

Could it be that the colour you perceive as ‘red’ is someone else’s ‘magenta’ – or even an entirely different colour?

 

Previously, researchers would probably have answered the question by saying that they assume that all human beings see colours in the same way, even though this is not one hundred percent certain because of the subjective nature of colour vision. This assumption was most likely influenced by the belief that the brain had a default way of light processing that was tied to emotional responses and was identical to all people. Thus, there was not really a reason to assume otherwise as the processes that were found to be involved in colour perception were found to be the same across people. Additionally, scientists believed that colour representation occurred solely visually in the human brain. Since visual representation is by definition an accurate and unbiased representation of a concept, scientists implied that people would memorize the colour that they have previously seen on an object as accurately as possible with little bias.

However, this view has begun to change in recent years, since for example, recent experiments with monkeys revealed that colour perception is highly related to our previous experiences of the outside world, making colour perception subjective. In other words, the way someone perceives colours is strongly tied to their own unique experiences and memories. That, in turn, makes it very possible that one person’s ‘red’ is another person’s ‘magenta’.  For example, a person’s unique experiences with language. The World Colour Survey discovered that people that are native speakers of languages that have a lot of terms for individual colours, such as English, could name colours more accurately than others (Kay, Berlin, Maffi, Merrifield, & Cook, 2009). Some scientists even go as far as to say that someone’s ‘red’ could also even be another person’s ‘blue’.

 

The way someone perceives colours is strongly tied to their own unique experiences and memories.

 

Nevertheless, some researchers are still unsure about the degree of difference between colour perceptions across humans, because differences in perception are difficult to test on living samples. Of course, testing with the help of surveys or interviews exist, however the accuracy of these measures cannot be checked as they rely on subjective responses. Another difficulty arises by the fact that the human eye can perceive up to a million of different colours. This creates so much variety that people cannot name all perceived colours with their limited language systems. In other words, even if we use the same color name for two different objects, that doesn’t mean we actually perceive their colors as identical. That makes researchers question whether people really do recognize colour in the exact same way, or if what they really see is clouded by the limitations of language, since languages mostly only have few categorical terms to describe colours.

However, even if the perceptual differences should not be as significant as assumed, there are still slight differences among humans in colour representation in the brain. That is because the colour representation, especially in regard to the visual working memory, can be prone to inaccuracies. Because our visual working memory is a limited cognitive system, it has to prioritize some items over the others. And thus, as priorities differ between each person, some colours are remembered slightly differently by each person. How accurately the colour is remembered and what the individual focuses on is based on several aspects, such as how many colours or objects you have to remember, how familiar you are with the colour and object, and how big the object is.

Since everyone differs in regard to these aspects, it can be estimated that people will perceive, and talk about, colours differently by default. For example, during a colour discrimination task, a painter –who is very familiar with a wide array of colours– would probably be able to name a wider array of colours and do so with more accuracy since she would have more experience in that domain due to using different colours during painting regularly. So, it can be assumed that a painter experience colours differently than, for example, someone who does not grapple with colours daily (such as a psychology student).

 

Even if we use the same color name for two different objects, that doesn’t mean we actually perceive their colors as identical.

 

An explanation for that is the fact that the colour representations of both people simply differ based on their knowledge on colours. Someone who is experienced with colours will probably have more accurate representation of the colour in their mind (visual representation; e.g. magenta), whereas someone with less experience will probably relate to the information they already know, perceiving a colour to be of a more generic or prototypic shade (categorical representation; e.g. red). So, in this case, it might be unclear if one person’s ‘red’ could be another person’s ‘blue’. However, these findings still suggest that one person’s ‘red’ could be another person’s ‘magenta’ at the very least. That is because red and magenta are colours that are related to each other and are only different in regard to their shades. The fine distinction between shades, then again, is based on factors such as knowledge and exposure.

Now, think again about the prettiest sunset you can ever imagine seeing outside of your window. Imagine how someone else is also seeing the sunset. The person tells you that the sunset is magenta. Knowing all of the information in the post, you probably ask yourself whether the person’s ‘magenta’ is your ‘red’. “Probably yes,” you think – and then you wonder which other colours you might experience differently. Is that not incredible?

 

Image credit: picture by Sagesolar (licensed under CC BY 2.0).

 

References

Alvarez, J. (2012). An Investigation of the Influence of Language on Colour Perception. University of Surrey, unpublished doctoral dissertation. Retrieved from https://www-proquest-com.proxy-ub.rug.nl/docview/2282036669

Bryner, J. (2009). Therapy Fixes Color Blindness in Monkeys. Livescience. Retrieved from https://www.livescience.com/5721-therapy-fixes-color-blindness-monkeys.html

Kay, P., Berlin, B., Maffi, L., Merrifield, W. R., & Cook, R. (2009). World Color Survey. Stanford, CA, US: CSLI Publications.

Marić, M., & Domijan, D. (2020). A neurodynamic model of the interaction between color perception and color memory. Neural Networks, 129, 222-248.