Unconscious associations with the sense of smell may influence color perception, British scientists report. “The presence of different odors influences how people perceive color,” said lead author Ryan Ward, Ph.D.
Our senses: sight, smell, hearing, touch and taste constantly receive stimuli from the environment. The brain tries to make some sense of this avalanche of sensations – for example, by combining information from two or more senses – smell, texture, color, size, melody.
When people make unconscious, stereotypical connections between two or more senses, cross-modal associations arise. That is why, for example, we associate higher temperatures with warmer colors, lower sound tones with a lower location, or the color of an orange with its taste.
A new experimental study by British scientists has shown that unconscious associations with the sense of smell can influence color perception.
“We show that the presence of different odors influences how people perceive color,” said lead author Dr. Ryan Ward, a lecturer at John Moores University in Liverpool, UK. An article on this topic was published in early October in Frontiers in Psychology.
Smell and smell. How can they influence each other?
What did the research look like? Ward and his team examined the strength of associations between smell and color in 24 adult women and men aged 20 to 57. Participants in the experiments sat in front of a screen in a room free from unwanted sensory stimuli. They did not use deodorants or perfumes. None reported being colorblind or having a sense of smell. To initially remove odors from the environment, the air purifier was turned on for four minutes. Then, one of six scents (caramel, cherry, coffee, lemon and mint, and odorless water as a “control odor”) was emitted into the room using an ultrasonic diffuser for five minutes. “In a previous study, we showed that the smell of caramel is often associated with dark brown and yellow, just as coffee is associated with dark brown and red, cherry is associated with pink, red and purple, mint is associated with green and blue, and lemon is associated with yellow, green and pink,” Ward explained. Participants were shown a square filled with a random color (from an infinite range) on a screen and asked to manually adjust two sliders – one for yellow to blue and one for green to red – to change the color of the square to neutral.
After the final selection was recorded, the procedure was repeated until all odors had appeared five times. As it turned out, participants had a weak but significant tendency to move one or both of the sliders too far from neutral gray. For example, when exposed to the smell of coffee, they incorrectly perceived “gray” as more reddish-brown than the true neutral gray. Similarly, when they were exposed to the smell of caramel, they mistakenly perceived the yellowish color as gray. The presence of the odor therefore predictably disrupted participants’ color perception. The exception was the smell of peppermint: in this case, the participants’ choice of shade differed from the typical association shown for other scents. As expected, participants’ choice also matched true gray when presented with a neutral water odor.
“These results show that the perception of gray skewed towards the expected cross-modal associations for four of the five odors, namely lemon, caramel, cherry and coffee,” Ward explained. “This ‘overcompensation’ suggests that the role of cross-modal associations in sensory processing is strong enough to influence how we perceive information received through different senses, in this case between smells and colors,” he added.
The researchers emphasize the need to investigate how far-reaching such cross-links between scents and colors are. – We need to know to what extent odors influence color perception. For example, does the effect shown here still hold for less common scents, or even for scents encountered for the first time? Ward pointed out.
Main photo source: Shutterstock