Pandora has shared a new collection of seven color-inspired playlists associated with the seven primary colors (ROYGBIV). Titled Somewhere Over The Rainbow: The Science of Sound and Color, the playlists actually seek to capture what blue or orange sound like, rather than just making playlists that have the color in the song title.

In a press release, Pandora stated that the inspiration for the playlist comes from synesthesia, a condition in which a person experiences one sense through another (hearing colors or tasting sounds). Contemporary artists like Billie EilishPharrell, and Lorde are all synesthetes, according to the release, and many believe abstract art pioneer Wassily Kandinsky also suffered from the malady.

Related: L4LM Monthly Mix – August 2020 Listening Guide [Playlist]

It turns out that pairing sounds and associated feelings and colors isn’t just the work of music journalists, but a field of growing research called crossmodalism. Steve Keller, Pandora’s Sonic Strategy Director, notes in an essay accompanying the playlists,

When our senses are simulated, our brains look for congruent connections that help inform our perception of what we taste, hear, touch, smell or see. We can use these crossmodal associations to “hack” our sensory perception. For example, we tend to associate high pitched sounds with sweetness, and lower pitched sounds with bitterness. Experiments have demonstrated that same piece of chocolate might taste sweet or bitter, depending what we put into your ears while you’re eating it. Our language is full of these comparisons: we talk about how something might “sound” sweet or dark, or we might refer to the “notes” of flavor and aroma in wine.

The same is true when we examine “crossmodally congruent” sound and color pairings. Fast paced music in a major key is associated with bright, vivid colors like yellow. Increase the tempo and energy and blend in a little distortion and you’ll be seeing red. Slow down the tempo, move into a minor key, lessen the attack of the notes, and you might be feeling blue. The lower the pitch the darker the hue. The higher the pitch, the brighter the hue.

Keller goes on to outline a sort of index for what sounds translate to what colors and so on. It was this research that lead him and the Pandora team to create the seven Somewhere Over the Rainbow playlists. The red playlist is connected to faster, upbeat tempos that lend heavily from salsa. Meanwhile the blue playlist, the color our brains most associate with jazz, features relaxed rhythms with low pitches. The playlists include contemporary artists and range all the way back to classical music, with some artists (like Mac Miller) featured on multiple colors.

See all seven color playlists from Pandora below and read Keller’s essay diving into the science of crossmodalism here.

Hearing Red
Red is the color that scores higher on emotional scale of arousal and excitement. Higher pitches, faster tempos, fast attack and strongly rhythmic percussion are the triggers that help our brains “hear” the color red.

Hearing Orange
Not quite as sonically exciting as red or as playful as yellow, music associated with the color orange tends to be a bit slower in tempo, lower in pitch, and rougher around the edges than other colors at the lower end of the visible spectrum.

Hearing Yellow
Yellow is the color of “playfulness and sunshine.” Sonic associations with yellow draw on major keys, brighter timbres, light and lively rhythms, and simple harmonies.

Hearing Green
Green is often associated with nature. Organic instrumentation, simple harmonies, relaxed tempos and intimate vocals are all strong sonic associations with the color green.

Hearing Blue
Sonically, blue draws on slower tempos and more relaxed rhythms. Lower pitches and instruments like piano and strings allow for more expression and produce the sense of calm that’s often an emotional association with the color blue.

Hearing Indigo
Darker than its cousin purple, indigo is sonically represented by lower pitches, darker timbres, slower tempos, and gritty rhythms that form a musical tapestry both delicate and delicious.

Hearing Violet
Not as dark as its cousin purple, indigo uses sonic building blocks that include higher pitches, warmer timbres, and percolating rhythms that are full of swagger and groove.

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