What colour is the smell of soap?

We are often unaware of how much our sense of smell can affect our mood or even our behaviour. Smelling food can tell us we are hungry and so we eat. Smelling the fragrance or body odour of a lover can arouse us or make us feel safe. Smelling the scent of our house as we walk through the door can make us feel relaxed. But an odour can also be very jarring when it is smelled out of context. You might smell your lover’s fragrance on someone else and have an instantaneous emotional reaction that seems out of place. You might smell the same diffuser oil that you have in your home in a crowded store and feel a sense of calm when you would typically feel anxious. Luca Turin, a scientist and writer who works primarily with fragrance described this feeling very eloquently in his book The Secret of Scent:

What was strange about the fruity whiff was what was missing: colour. The grey of the concrete, the pleasant wind in the blue sky, the green of the English countryside – all were accounted for, pictures and smells present and correct. Suddenly this huge orange-coloured smell comes out of nowhere. To justify its presence, there should have been a pile of ripe fruit one hundred metres high, but there was nothing, only a light breeze coming from a nondescript building. This severing of effect from cause is one of the wonders of smell. It gives it a quality of hallucination... (Turin, 2006 p.9)

Turin is talking about an experience he had walking into a perfumery firm and smelling a powerful fragrance that seemed out of place according to his surroundings. Colour is probably one of the strongest associations we have with smell and, for the most part, this is a result of the environment in which one grows up.

In a study published in PLOS One in 2014, 122 subjects from six different cultural backgrounds were given a variety of odours that occur across cultures and asked to choose the most congruent and most incongruent colours. In this study, the researchers left out verbal language entirely in order to eliminate any potential semantic factors. Their goal was to map out colour associations across cultures to see where similarities and differences occurred within a specific cultural group and between different cultures. The researchers were also looking at whether these associations were structural (caused by a mechanism within the brain) or statistical (caused by exposure to the same two stimuli over time - i.e. the colour yellow and the scent of a lemon). Since the researchers found no associations that were universal across cultural groups, it could be concluded that none of the associations were structural. There were, however, a few similarities between cultures - most groups choose pinks and reds for the floral and fruity scents, greens for the vegetable scent, and browns and oranges for the hazelnut and musky scents (Levitan et al., 2014). This is likely in large part due to cultural conditions such as consumer products and marketing. For example, Americans overwhelmingly chose pinks and reds for the fruity scent - perhaps on account of the predominantly pink and red colours of fruit-scented body and room sprays, candles and candies that are sold in the US. The scent of soap, on the other hand, was a bit more contentious - some participants paired it with white or pastel colours, while others chose yellow or browns. There wasn’t much continuity even within the cultural groups. This might suggest that people have a different association with the colour of soap depending on what brand they buy and that there are a wide variety of colours within the soap market. Figure 1 shows the frequency of colours chosen for each scent within the different cultural groups.

Figure 1 (Levitan et al., 2014)

Our cultural preconceptions of colour-scent relationships can influence the way in which we interpret a scent. For example, in western culture, if a person is surrounded by brown and tan colours, he or she is much more likely to interpret a scent to be “earthy” or “musty” than if that person were looking at bright pinks and reds. It’s no wonder that companies like Yankee Candle colour their products in a way that suggests the fragrance they want to convey, according to cultural expectations. They want to convince consumers that their portrayal of a scent is accurate and leave little room for interpretation. Looking at a raspberry pink candle will lead the consumer to believe that what they are smelling is indeed the authentic smell of raspberry sorbet that the label suggests. Artist Miriam Songster challenged these cultural preconceptions of colours and odour in her piece “The Green Scent of Pink”. The installation, exhibited in 2005, consisted of a pink room with the smell of grass. Though very simple, this gesture sends a strong message about how we associate smell with colour and are virtually unaware of these associations until they are interrupted.


This is an excerpt from my MA dissertation entitled How Crossmodal Relationships and Language Affect Our Understanding and Use of the Sense of Smell. If you'd like to read more, pop your email in the "stay updated" box below to be notified when more excerpts are up on my blog or click here to download the entire dissertation for £1.99 from Amazon. Your support is really appreciated!