LIVERPOOL, United Kingdom — Have you ever associated the taste of oranges with its vibrant color? Or perhaps linked the pitch of a sound with its height? Our brains continuously make these “crossmodal” connections, merging information from two or more senses to help us understand the world around us. Now, researchers from Liverpool John Moores University in the United Kingdom reveal how our sense of smell can influence our perception of colors.
“Here we show that the presence of different odors influences how humans perceive color,” says study lead author Dr. Ryan Ward, a senior lecturer at Liverpool John Moores University, in a media release.
To delve into this phenomenon, Dr. Ward and his team placed 24 participants, all between the ages of 20 and 57, in a room specifically designed to minimize any unwanted sensory distractions. In this controlled environment, devoid of external scents and sounds, participants were exposed to one of six different odors – caramel, cherry, coffee, lemon, peppermint, or simply odorless water as a control.
“In a previous study, we had shown that the odor of caramel commonly constitutes a crossmodal association with dark brown and yellow, just like coffee with dark brown and red, cherry with pink, red, and purple, peppermint with green and blue, and lemon with yellow, green, and pink,” explains Dr. Ward.
Participants were then shown a colored square on a screen and were asked to adjust its color to a neutral grey, using two color-changing sliders. This process was repeated multiple times for all the various odors.
The volunteers’ choices revealed a consistent pattern. When the scent of coffee wafted in the air, participants tended to shift the color more towards red-brown than an actual neutral grey. Similarly, the aroma of caramel led them to perceive a bluish tint as grey. However, there were exceptions. Peppermint’s odor didn’t match its usual crossmodal associations, and, unsurprisingly, water’s neutral scent led participants to select the true grey.
“These results show that the perception of grey tended towards their anticipated crossmodal correspondences for four out of five scents, namely lemon, caramel, cherry, and coffee,” says Dr. Ward. “This ‘overcompensation’ suggests that the role of crossmodal associations in processing sensory input is strong enough to influence how we perceive information from different senses, here between odors and colors.”
Dr. Ward highlighted the need for further research, questioning, “We need to know the degree to which odors influence color perception. For example, is the effect shown here still present for less commonly encountered odors, or even for odors encountered for the first time?”
The study is published in the journal Frontiers in Psychology.
Studies have also linked smells to the brain and memories
A team at the Champalimaud Centre for the Unknown previously found that it all comes down to neurons in the brain.
These brain cells in the olfactory cortex – the area of the brain that controls smell – make the link between specific scents and places. Smell often has the power to transport us through time. It could be the calming fragrance of lavender that brings someone back to their childhood home or the smell of cinnamon that transports your mind back to a Christmas with loved ones.
“Odor molecules do not inherently carry spatial information. However, animals in the wild use odors for spatial navigation and memory, which allow them to locate valuable resources such as food” says postdoctoral researcher and study first author Cindy Poo in a media release.
“Humans rely on visual landmarks more than odors, but it’s likely that the principles of how we remember where we’ve been and get to where we’re going are very similar.”
