Visual words like "light" and "dark" are often used to describe musical compositions in emotional terms, and the blues associate music with both color and mood.

Such linking between emotion, color, and music isn't just metaphorical, suggests a new study from UC Berkeley - our brains instinctively associate different types of music with certain colors, with a universal "emotional palette" that underlies our senses.

Researchers from UC Berkeley found that people in both the United States and Mexico associated the same pieces of orchestral music with the same colors.

When choosing from a 37-color palette, participants tended to associate lively music in major keys with vivid yellowish colors, while somber music in minor keys was linked to dark blues and grays.

"The results were remarkably strong and consistent across individuals and cultures," said lead researcher Stephen Palmer in a news release.

In 95 percent of cases, he said, his team could predict how "happy" or "sad" the colors participants chose would be based on the moods elicited by the music.

The findings, published in the journal Proceedings of the National Academy of Sciences (PNAS), suggest that emotions strongly influence how the brain maps connections between seeing colors and hearing music.

How Does Color Sound and Feel?

Over the course of three experiments, 48 participants in the San Francisco Bay area and 49 in Guadalajara, Mexico, listened to 18 classical orchestral music pieces by the composers Johann Sebastian Bach, Wolfgang Amadeus Mozart and Johannes Brahms.

The melodies were whittled down to 50-second samples that varied in tempo from slow, medium, to fast, and were in either major or minor keys.

In the first experiment, the participants had to choose five colors from a palette of 37 that they felt most closely matched the music samples they heard. The palette included nine colors at four levels of saturation, from vivid to dark: red, orange, yellow, chartreuse, green, cyan, blue, and purple.

The results showed that participants reliably chose brighter, yellower colors to go with the more upbeat music in major keys, like Mozart's Flute Concerto No. 1 in G major. Sadder selections in minor keys, like Mozart's Requieum in D minor, were more likely to go with darker, bluer colors.

In two follow-up experiments, participants were asked to relate facial expressions that were sad, happy, or angry to the music selections they heard, and then to colors from the same palette.

The results suggest that "common emotions are responsible for music-to-color associations," said Karen Schloss, a co-author of the paper, in the press statement.

People tended to match happy faces to upbeat music and bright colors like yellow and orange, and sad faces to music in minor keys and darker bluish and greenish colors. Angry faces were linked to dark red colors.

Synesthesia: When Senses Blend Together

The tendency to emotionally link colors with music is likely distinct from synesthesia, a unique neurological condition in which different senses automatically blend together in complex combinations like tasting sounds, smelling colors, or hearing textures.

Synesthesia was popularized in a striking sequence in the Pixar film Ratatouille, in which Remy the rat experiences abstract visual and musical cues along with the taste combinations in his mouth.

Over 35 different subtypes of synesthesia may exist, according to researchers at Boston University. Among the more common ones are color-graphemic, in which certain letters or numbers are perceived to have specific colors, and color-auditory, in which sounds are linked to colors and other visual stimuli.

The condition is present in as much as 4 percent of the population, according to a study cited by the researchers David Brang and V.S. Ramachandran, and can be triggered by drugs, sensory deprivation, or brain damage in people who don't otherwise experience it. It may even be something that most young children have, but that we grow out of as our brains develop specific sensory pathways.

Synesthesia seems to be more common among artists and writers (famous examples include Wassily Kandinsky and Vladimir Nabokov), perhaps giving them a wider range of ways to describe the world we all live in.

Is Everyone a Little Bit Synesthetic?

While the people in this study felt emotions that associated music with certain colors, Stephen Palmer explained in an email to Medical Daily, synesthetic people experience sensory blending without necessarily having strong emotional associations about their perceptions.

Previous studies in his lab have shown that synesthetes' color experiences to the same classical music do not have the same robust emotional effect that non-synesthetes displayed, suggesting a direct mapping from sound to color in the brain that is not mediated by emotion.

It's poorly understood how and why synesthesia develops, but Palmer is open to the idea that similar emotional mechanisms are at work in synesthetes' perceptions - they might just be more muted.

"Perhaps emotional experiences from early childhood have become 'frozen' into their direct neural mappings from music to colors, which then last into adulthood," he suggested, though investigating that would require experiments that are difficult to execute.

That might suggest that cross-sensory associations exist at different levels for all people, with synesthetes experiencing the most intense ones, but there isn't much evidence for such a clean spectrum.

"The striking regularity of the color associations indicated by non-synesthetic people to the classical orchestral music studied in the PNAS article suggests the possibility of a continuum of some kind between synesthetes and non-synesthetes.

"However, further research with music-to-color synesthetes using much simpler and better-controlled musical stimuli (single-line piano melodies by Mozart) indicates a weaker role for emotion in the colors synesthetes experience and one that may arise from different underlying brain mechanisms."

That is to say, the sensory experiences of people with synesthesia might just be fundamentally different on a neural level.

In future research, Palmer and his team will study how people in non-Western cultures associate colors and music, particularly in ones that use a broader range of scales than just major and minor.

"We know that in Mexico and the U.S. the responses are very similar," he said. "But we don't yet know about China or Turkey."

In the meantime, he suggests, the findings could help artists and computer programmers design more compelling music visualizers on iTunes. If nothing else, that could make listening to your favorite tracks much more emotionally engrossing.


S E Palmer, K B Schloss, Z Xu, and L R Prado-León. Music-color associations are mediated by emotion. PNAS .2013.