Thinking in colour

soleils-leDiP-gHnWQ-originalWe live our lives in vivid colour. As I write, there is a yellow lamp, a blue notebook and a red teapot on the desk beside me. These colours are not connected with the functions of the objects, or even with the materials they are made from. The teapot, for example, was also available in white, grey, black, orange, yellow, green, blue and turquoise. Colour tastes are notoriously fickle, from avocado bathroom suites to nude heels. Some colours may, however, have a power to influence our feelings and our behaviour regardless of the vagaries of fashion.

Humans began changing the colours of our world, and ourselves, almost 100 thousand years ago. The first artificial pigments were derived from red ochre, a mineral taking its colour from oxidised iron, and probably used for body adornment. Yellow ochre, chalk and charcoal later enhanced the vividness of stone-age cave paintings. The Making Colour exhibition at the National Gallery in London shows how artists over subsequent millennia laboriously developed new pigments for their paintings.

These technological advances led to magnificent works of art, but also to teapots, t-shirts and telephones of a thousand arbitrary colours. As the psychologist Nicholas Humphrey once said: “Colour anarchy has taken over.” In such a world, is it possible that any particular colour could have a distinct and reliable impact on our emotions and behaviour?

In many animals, sophisticated colour vision is not required for survival. Humans, apes and some monkeys are able to perceive a million or more colour distinctions, but this is much greater than most mammals. A red rag is nothing special to a bull: cows, dogs, cats, sheep and horses are all colour-blind to some extent. By contrast, many birds, reptiles and insects have much more sophisticated colour vision than humans. Indeed, the kaleidoscopic diversity of the natural world – including colours not visible to humans – arises because animals and plants use colour to signal to potential mates, predators and pollinators.

The variety of natural coloration and the power of colour perception co-evolved. Until complex life forms started sending visual messages to each other, there was little need for colour vision. “Rainbows and sunsets have no importance to survival,” said Humphreys. Since plants first began producing flowers for reproduction, about 125 million years ago, their patterns of coloration have become dependent on the creatures they need to attract for pollination. Red flowers, for example, are not designed by natural selection to attract bees – which can see ultraviolet but not red – and so are more likely to be pollinated by birds.

Our own visual system can distinguish red and green, useful to our primate ancestors for identifying red fruit against a background of green foliage. This power of colour detection depends on three sets of colour receptors in our eyes, roughly corresponding to red, green and blue. Activity in combinations of receptors allows us to sense our full range of colours, whilst a missing receptor underlies colour-blindness, most commonly the inability to distinguish red and green, in around 8% of men, but far fewer women. (In fact, some women have two types of red receptors, making them super-sensitive to colour.)

Naturally, psychologists have focused on these three key elements of our visual system when investigating the impact of colour on our behaviour and emotions, summarised in the Annual Review of Psychology by Andrew Elliot and Markus Maier. Both green and blue are, of course, prevalent in natural environments. Green dominates fertile landscapes, due to the chemical structure of chlorophyll, whilst the scattering and absorption of light – by air and water respectively – make the sky and the sea appear blue. Perhaps unsurprisingly, evidence suggests that both of these colours may have positive associations, such as openness and peace for blue, and calmness and success for green.

Red seems to be a uniquely provocative colour, associated with a variety of contradictory responses. Rhesus monkeys allowed to choose between plain screens of different colours showed a strong preference for blue or green over orange or red, with red inducing an actively fearful reaction. In humans, experiments have found red to be associated with emotional arousal, physical attractiveness, dominance, aggression and even sporting success.

Why should red be so powerful but also ambiguous? Almost certainly, the answer is blood. The combination of iron and oxygen that gives red ochre its pigment also colours the haemoglobin in our red blood cells. The spilling of blood could indicate danger, injury and death, but is also a key sign of fertility in humans and other primates. Red coloration is reliably associated with sexual arousal, and so red body adornment seems to have a particular allure. Both women and men judge other people to be more attractive when wearing red. Surprisingly, this is the case even when the red garment is not actually visible to the viewer – some of the power of red apparently comes from the feelings it induces in wearers themselves.

Of course, going to that first date dressed from hat to boots in red may not guarantee a second invitation. Laboratory experiments manipulate single features, but our day-to-day interactions are affected by a multitude of sensory cues and social experiences. And the interpretation of colours – particularly red – strongly depends on context. Facial redness could indicate sexual arousal, anger or exertion. That could be why those monkeys found plain red screens frightening: they know it is a signal, but have no way of knowing how to respond. In our world of infinite colour choices, that is something to consider next time we buy a teapot.

Liz Hellier writes:
Applied psychologists use the associations between colour and perceptions/behaviour when they design warning systems and warning labels. Studies show that different colours are reliably interpreted as implying different levels of hazard or danger, with colours such as red and orange implying more hazard, and green, blue and black implying less (e.g., Braun & Silver, 1995). We use such data to implement “hazard matching” in the design of warning systems, matching the hazard of the situation being warned about to the colour of the visual warning. Hazardous situations are indicated by colours that will be perceived as hazardous (e.g. red) and less hazardous situations are indicated by colours that will be perceived as implying less hazard (e.g. blue). Furthermore, colour not only influences how we perceive warnings, but also how we respond to them: people are more likely to comply with warnings that are presented in red (Braun & Silver, 1995).

Jon May writes:
Colour influences our affective responses. Boyatzis and Varghese (1994) found that children reported negative reactions to dark colours such as black. Terwogt and Hoeksma (1995) noted that black was associated with fear and was the least preferred out of the choice of six colours and Hemphill (1996) found that dark colours evoked negative emotional associations for participants, whereas bright colours had the converse effect of eliciting positive associations. Oberascher and Leonhard (2003) observed that participants associated the colour black with negative emotions such as fear and despair. Meier, Robinson and Clore (2004) found that adults were less accurate and slower at determining the valence of a word when presented in an incongruent colour. For example, they were slower at processing the positive word “happiness” when presented in black, than they were at processing the negative word “bully” when presented in black. It was concluded that people automatically assume that bright objects are good and dark objects are bad. Spector and Maurer (2011) suggest that a natural bias for humans to associate jagged contours with black and curved contours with white is due to their shared affective connotations.


Boyatzis, C.J., & Varghese, R. (1994). Children’s emotional associations with colors. The Journal of Genetic Psychology, 155, 77-85.

Braun, C. C., & Silver, N. C. (1995). Interaction of signal word and colour on warning labels: differences in perceived hazard and behavioural compliance. Ergonomics, 38, 2207-2220.

Elliot, A. J., & Maier, M. A. (2014). Color psychology: Effects of perceiving color on psychological functioning in humans. Annual Review of Psychology, 65, 95-120.

Hemphill, M. (1996). A note on adults’ colour-emotion associations. Genetic Psychology, 157, 275-280.

Meier, B.P., Robinson, M.D., & Clore, G.L. (2004). Why good guys wear white: Automatic inferences about stimulus valence based on brightness. Psychological Science, 15, 82- 87.

Oberascher & Leonhard (2003). Colour and emotion. Proceedings of A/C 2003 Bangkok: Colour Communication Management (pp. 370-374).

Spector, F., & Maurer, D. (2011). The colours of the alphabet: Naturally-biased associations between shape and colour. Journal of Experimental Psychology: Human Perception and Performance, 37, 484-495.

Photo credit: Seven Portraits via cc.

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One Response to Thinking in colour

  1. Jacqui Turner says:

    Red being the dominant colour may begin at a very young age. In 1975, Bornstein exposed infants to an array of colour and found that very young infants looked longer at the colour red (and blue) compared with the other colours, so showing a clear preference for some colours. It was also later shown that infants from as young as 4 months of age begin to categorise colours, and that at this age, they don’t seem to like the colour brown (Franklin, 2004). It’s interesting to see how quickly an infants’ visual system develops and how they perceive colours in an analogous way to adults (e.g., Zemach et al, 2007). Another interesting finding is that the perception of colour can be influenced by bilingualism, with a recent study showing that Greek-English bilinguals differentiate the colour blue, differently to English monolinguals (Athanasopoulos, 2008). In our world of limitless choices, another point to consider next time we buy a cup or a dinner plate, is that the colour red has been found to reduce snack food and soft drink intake (Genschow, 2012). Of course, going to that first date dressed from hat to boots in red, and clutching an armful of red plates, bowls and cups might just set those alarm bells ringing.

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