Seeing red? The power of colour over the mind
Red makes us more attractive, blue more alert, while pink can sap a man's strength. Once dismissed as hippyish, the science of colour is finally being taken seriously. By Tom Chivers
Published 13/05/2014 | 02:30
'The idea colours affect our mood – that red makes us angry – seems hippyish''Some think that primates developed the ability to detect red due to bare faces'
I f you give the patient one pill, he perks up. If you give him another pill, he calms down. That might not surprise you. What might, though, is that it still works even when the pills contain no actual medicine.
Studies show that red pills are more effective stimulants than blue pills; blue pills are more effective as sleeping tablets than orange tablets. Green, white or blue pills aren't as effective as red ones as painkillers. But these were all placebos, administered in experiments in the Sixties and Seventies. There was no painkiller, no stimulant.
The idea that colours affect our mood – red makes us angry, or sexually receptive; blue soothes us, or saddens us – that sort of thing, seems vaguely hippyish.
But now, the body of scientific research into colour is growing. And it all points to one thing: our perception of it really does affect minds and bodies.
A 2004 study found that football teams wearing red were statistically more likely to win than teams in other colours. Another, in 2008, found that male volunteers shown photos of averagely attractive women on red and white backgrounds rated the women on red as more good-looking. Meanwhile, an experiment in the Seventies found that male prison inmates became physically weaker when they were housed in pink-painted cells.
And yet, while its effects on us may be profound, colour "doesn't really exist in the world", says Beau Lotto, a neuro-scientist at University College London. Blue is how our eyes interpret wavelengths of electro-magnetic radiation. Red is how our eyes interpret another, longer set.
We have three different colour receptors, cones, in our eyes, each designed to pick up different wavelengths of light. These are red, green and blue. Most mammals, apart from a few of our fellow apes, have two, and so do most colour-blind people, meaning they can only detect green and blue wavelengths. If we had one receptor, we'd see the world in something like black and white.
This is the product of billions of years of evolution. Back when our ancestors were single-celled organisms, they had basic light sensitivity, and would have been able to some degree to detect differences between long-wavelength and short-wavelength light. This would have allowed them to tell when it was daylight (blue light) and sunset (red light). Later, as lifeforms grew more complex, we developed more sophisticated techniques for more sophisticated purposes.
"The whole point of colour vision is not to inspire poets, but to allow contrast detection," says Russell Foster, professor of circadian neuroscience at the University of Oxford. "You've got a much better chance of detecting an object against a background if you have colour vision."
Birds are masters at this, he says, having four colour detectors. They see things that we see as a single red as an infinite wash of colours.
Unlike birds, mammals are descended from small, timid creatures who scurried around avoiding dinosaurs – and, crucially, were nocturnal. Our ancestors had less use for colour detection.
It was only after the death of the dinosaurs 65 million years ago that our forebears ventured out in daylight, and it is 30 million years or so since a mutant ape got a third colour receptor.
Nonetheless the wavelength of the light around us still affects us. Foster, who researches the effect of light on sleep, says that our circadian rhythms – our 'biological clock' – are profoundly affected by not just the brightness of the light, but the colour of it. He discovered a cell in the optic nerve which acts as a sort of photon-counter, keeping track of how much light has hit it in the last few minutes. It is especially sensitive to blue light – specifically, the blue of a blue sky. If you're exposed to light of this colour, it will make you more alert. "Blue light keeps us awake far more effectively than red light," he says.
Beau Lotto says context is all: red is friendly when associated with ketchup and baleful when associated with blood.
Lotto spends much of his time creating optical illusions to demonstrate how humans see and perceive colour, and the impact of context upon it. "I can take a grey patch, and cause you to see any colour in it," he says. "I can make you see blue or yellow, depending on what surrounds it. When I change your perception of it, what I'm changing is the meaning of the information, I'm not changing its physics.
"If I make a patch appear as if it's under shadow, you'll see it as being lighter than if I make the same patch appear as if it's on a dark background. That's what your brain is constantly doing."
The illusions are remarkable to look at, and unsettling to see, at least for me: they undermine my sense of being grounded in reality.
But we're not uniformly sensitive to these illusions; again, context matters. "How powerful people feel alters their perception of colour," says Lotto. "If I make you feel a bit more powerful, a little more in control, the strength of the illusions that I make decreases. If I put you in a state of powerlessness, the strength of illusions increases."
There's some indication that the words we use to describe colour affect our ability to see it. Benjamin Whorf, a linguistic theorist, claimed that our language limits our perception: if our language lacks a word for something, we find it harder to think about that thing.
The Whorfian hypothesis has been largely discredited – after all, if we really couldn't think about things we didn't have a word for, we wouldn't need to come up with new words; English didn't have a word for 'schadenfreude' until recently, but we understood the concept well enough.
Nevertheless, experiments have shown that societies which lack different words for blue and green find it harder to find the odd one out in a group of greenish-blue squares. The fact that we distinguish indigo and violet as separate colours is largely down to Isaac Newton, who named and split the colours of the rainbow more subjectively than scientifically, leaving a large area between blue and green un-named.
The cultural contexts and meaning of colours has been picked up by marketers, as suggested by the title of a paper in the Journal Of The Academy of Marketing Science, 'Exciting red and competent blue: the importance of color in marketing'. White is 'purity, cleanness, simplicity, hygiene, clarity and peace'; black is 'sophistication, glamour, status, elegance, richness and dignity'. Purple is status, pink is femininity, and, of course, blue suggests competence while red is exciting. Using these colours in your brand or logo, apparently, will subtly instil those messages in potential customers' minds.
A lot of these highly specific claims are probably hogwash, as another paper, in journal Color Research & Application, made clear in its own title: 'Colour psychology and colour therapy: Caveat emptor'. The evidence-based hypotheses are often hard to tease out from the mystical or made-up nonsense, writes its author, Zena O'Connor: "The information available is often presented in an authoritative manner exhorting the reader to believe a range of claims such as red is physically stimulating and arousing and blue is calming and healing.
However, evidence is rarely cited and, when it is, it's often in reference to findings inappropriately generalised or out-of-date."
But colour clearly still has a profound impact on our mental life.
An obvious question is how much of this impact is innate, and how much is learnt. For instance, the study into the psychological effects of pink, mentioned above, was carried out by Alexander Schauss in the Seventies. It showed that of 153 male prisoners put in cells painted pink, 98.7pc were weaker after 15 minutes – presumably because of associations with the colour and femininity. But pink has only been associated with girls for 70 years or so; would the same result have been found in Victorian times? Probably not.
But the red/blue lights distinction Russell Foster refers to must be written in our genes. The allure of red certainly appears to cross cultural boundaries. A 2012 study conducted in Burkina Faso, where red has negative associations, revealed it to be a sexual trigger. Paintings with red fetch higher prices than those without, and Brett Gorvy, chair of contemporary art at Christie's international, has described it as the "most lucrative colour".
Some scientists believe that primates developed the ability to detect red because of bare-skinned faces. Suddenly, we could 'read' expressions of anger, dominance and sexual readiness.
But natural selection doesn't care if you have a true representation of the universe. It only cares if you can find food and attract mates and avoid predators.
"Your perception of colour either helped you behave usefully towards this thing, or it didn't," Lotto says. "If it didn't, you died, and got selected out through evolution.
"And that, to me, is why colour vision is wonderful," says Lotto.
"You begin looking there, and it opens up all these other questions."
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