Smells Distort Color Perception, Says Liverpool Study

Liverpool John Moores University finds odors influence how humans perceive colors, adding a new dimension to sensory perception.

<p>Our brain is known to combine information from multiple senses – we might link smells with smooth textures, colors, or musical pitch. PHOTO BY ELLY JOHNSON/UNSPLASH </p>

Smells distort the colors we see, according to a new study.

Our brain is known to combine information from multiple senses – we might link smells with smooth textures, colors, or musical pitch.

For example, we link higher temperatures with warmer colors, lower sound pitches with greater depth, and the taste of oranges with the synonymous color.

Scientists at Liverpool John Moores University discovered smells warp our color perception, adding a new dimension to our understanding of sensory perception.

For example, when participants smelled coffee they mistakenly thought the grey color was more of a red-brown.

Our brain is known to combine information from multiple senses – we might link smells with smooth textures, colors, or musical pitch. PHOTO BY ELLY JOHNSON/UNSPLASH 

Likewise, caramel scents led them to see blue as grey.

The distortion was predictable, too.

Dr. Ryan Ward, Liverpool John Moores University, said: “Here we show that the presence of different odors influences how humans perceive color.

“In a previous study, we had shown that the odor of caramel commonly constitutes a cross-modal 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.

“These results show that the perception of grey tended towards their anticipated cross-modal correspondences for four out of five scents, namely lemon, caramel, cherry, and coffee.

“This ‘overcompensation’ suggests that the role of cross-modal associations in processing sensory input is strong enough to influence how we perceive information from different senses, here between odors and colors.

Our brain is known to combine information from multiple senses – we might link smells with smooth textures, colors, or musical pitch. PHOTO BY ELLY JOHNSON/UNSPLASH 

“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?”

For the study published in Frontiers in Psychology, the team tested 24 adult men and women between 20 to 57 years old.

The cohort sat in front of a screen, in a room without any sensory stimuli beyond the tests.

They wore no deodorants or perfumes, and none were color-blind or struggled to smell.

In the isolation room, all ambient smells were purged with an air purifier for four minutes.

One of six odors – caramel, cherry, coffee, lemon, and peppermint, or odorless water as a control – was released into the room for five minutes using an ultrasonic diffuser.

A screen was presented to participants, which showed a square filled with a random color.

They were invited to adjust two sliders until they changed the color to neutral grey.

A slider was for yellow to blue, and another from green to red.

The test was repeated until each odor had been presented five times.

It revealed participants had a weak but significant tendency to adjust the sliders too far from neutral grey.

Produced in association with SWNS Talker