How and why colour makes us feel

20 March 2020

Interview with 

Professor Anya Hurlbert, Newcastle University

COLOURFUL_FLOWER

this is a colourful flower

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Over the course of this and last month’s Naked Neuroscience episode, we’ve discussed how colour vision works in humans, how colour vision can vary and how it’s tested for, and how our colour-sensing abilities compare with those of other animals. But what about our cultural, linguistic, and emotional associations with such a ubiquitous thing as colour? Newcastle University’s Anya Hurlbert spoke to Katie Haylor. And as it turns out, light is far from just being a visual experience…

Anya - We respond to light coming off objects in order to see objects, but we also respond to light itself and our eyes are flooded with light from the room, from the surroundings, from the environment, generally we call that ambient illumination. And the light that's flooding our retinae at the back of our eyes is also stimulating receptors that are not involved in conscious vision, are not involved in helping us to reconstruct colours of objects and recognise them. They're involved in modulating our overall mood, behavioural level of alertness, sleep/wake cycle and our overall behavioural and cognitive function. And these receptors are part of what we call the non visual pathway. So we not only see light and see objects, we also feel light and respond to it in non-visual ways.

Katie - Is this part of the reason why, say if you've got somebody who's very poorly in hospital, say they're in intensive care, and they're in a coma, maybe they're not conscious, but light is still really important in terms of stimulating their circadian rhythms, which may be a bit lacking if you're in a hospital.

Anya - Yes, exactly. In fact, getting the light environment right in hospital rooms, which are not exposed to daylight is really important and is now being made more possible by the advances in lighting technology so that light spectra can now be tuned in real time to match natural daylight. And this is really important in helping to regulate the sleep wake cycles, not only of patients but also of the staff.

Katie - So from the unconscious to the conscious then, I want to ask you about emotion because colours are loaded culturally, linguistically! You know, "I just saw red", and maybe went into a rage. There is so much going on.

Anya - Yes!

Katie - What is the science behind colours affecting how we feel?

Anya - It really is true that colours, sort of more than any other visual attribute like texture, or emotion, seem to reach right down there into emotion and they have a close connection to the limbic system. And that's true anatomically. So the areas in the brain that analyse colour are actually located quite close to the deep seated emotional areas of the brain. And I don't think it's any accident, therefore, that colours readily evoke intense feelings in people. Vision scientists think that there might be a link in evolution between the emotional responses that objects aroused in us and the colours that they are. So that we developed a means of using colour as a sort of proxy for other properties of objects. And then we transferred those properties of objects to our feelings about the colours.
So that might sound sort of abstract, but we can think about the classic one of trying to find red berries amongst green foliage. So we're looking for the ripest, juciest, most maximally nutritious berry. We just scan for a deep saturated red and we find that and we pick that and that makes us survive better and it makes us feel good. So we start to associate that positive feeling with that deep saturated red. And eventually we abstract our response to the berry and apply it to the red.

Katie - Oh I see, so if a colour affects your emotion, then it can also affect your behaviour?
Anya - Yes.

Katie - If you're someone like me who loves listening to, reading about, watching interior design shows, you hear a lot about colours, you know, painting your bedroom, a certain colour, or your bathroom a certain colour. How rigorous is the science when it comes to creating your environment to be a certain colour to affect how you feel?A classic example is sleep, are there colours that are just genuinely better for sleep?

Anya - Well it's very interesting because there's so many different factors that can affect your emotional response to colour and the way it makes you sleep or the way it keeps you awake. And so teasing those apart is quite important because we have individual differences in our preferences for colour and they might depend on, in our lifetimes, which particular objects have we associated with particular colours. So I might particularly like green because my room was painted bright green when I was a child, but other people might look at green and think of snot or slime and therefore have a rather bad reaction to it. So there are individual differences in our preferences for colours. And that might influence, say, what colour we like our walls to be. That's one area.

Then we have the other area of our non-visual response to light. And the fact that there's this non-visual pathway that feeds directly into the parts of our brain that set our circadian rhythm means that, universally, very bluish light will tend to wake people up. And that's something we can say that's absolutely true. Whatever your preference for object colour. So a light with more short wavelength content, bluer light, with enough power in the short wavelength part of the spectrum will tend to keep you awake and that will then affect your sleep. So you really do need to think about responses to colour and responses to light on many different levels in order to understand why something might or might not help you sleep.

Katie - I've got to ask, do you have a favorite colour?

Anya - I do have a favorite colour and you know, I'm just very, very common in that way. I like blue and I mean way back, you know, at the Chicago world expo in the late 1900s, Joseph Jastrow showed that about 4,000 people picked blue as their favourite colour. So not unique!

Katie - We mentioned colour and emotion and you said it's not massively surprising to you that they are so closely linked. I think you're looking at this in the context of development though, right?

Anya - I'm also interested in at what stage of life these colour preferences develop, yes. But also whether there are any universals in colour preference. There are, as I said, universals in terms of non-visual responses to light. But can we pin down any universals in terms of emotional responses to colour? I'm not so sure. We know there are huge cultural influences. We know there are huge sex differences, but at what stage in development these arise is still not really clear.

Katie - Another thing we mentioned in terms of culture was language. You hear that some languages have so many different words to describe certain colours, but certainly if you go into a paint shop, there's myriad list of different adjectives that we put on colour. Do we know very much about language and colour? I'm wondering if people who speak certain languages have different relationships with colour than other people?

Anya - Absolutely. And it's been shown by many other groups that where certain languages such as Russian have different words for light blue and dark blue, they actually perceive those as different categories in the same way we Westerners perceive blue and green as very distinct categories. So there is definitely a relationship between language and perception and this does appear to come about at the stage of development where you would expect it to come about when language terms are being learned. There's a hypothesis, which there's a lot of evidence for, that language helps to shape perception, that the meer learning of linguistic terms helps to shape the colours that one perceives in terms of creating the boundaries between colours that we clearly put into different categories.

Katie - That's so interesting. Does that therefore mean that if you develop a bit differently to most people, your perception of colour and your emotion to it could be different?

Anya - Short answer - absolutely, yes. I think the individual variations in the way people see, respond to, and label are enormous and that each individual sees the world completely differently and there's really no way to get inside somebody else's head and perceive and respond to colours in the same way they do.

Katie - Oh, so does that mean the age old philosophical question that kids ask, "is that green, my green, the same as your green?" Is that always just going to remain a question?

Anya - I think it will, but I don't think that's a problem, I don't find that a kind of cop out or anything. I just think it means we have lots more to study.

Katie - And finally, on the subject of green, there is a lot of association at the moment with green and wellbeing. Do I need to paint my house green? Is this going to make me feel better?

Anya - Only if it really would make you feel better, for whatever reason! Your personal preference should be the thing that absolutely holds sway. Green doesn't necessarily have the same connotation for everyone, and green tends to be a background colour, because in the natural world it's foliage or it's grass. It takes up huge swathes of visual space that's meant to be sort of background against which other objects appear. Flowers or fruit or people. So green, you might think, "well, yes, it's probably quite a good colour to put on walls because it will sort of fade into the background and that's what you want walls to do". But you should never paint a room simply because someone tells you should paint it that colour! [laughs].

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