Radiolab: “Colors” (May 21, 2012) — Episode Summary

Main Theme and Purpose

Radiolab’s “Colors” delves into the science, history, perception, and language of color. Through stories ranging from Isaac Newton’s experiments with light to the cultural evolution of color words, the episode explores where color exists: in the physical world, in our minds, or somewhere in between. The hosts, Jad Abumrad and Robert Krulwich, uncover how color is perceived by different species, how human genetics and language shape color vision, and the surprising, sometimes haunting origins of the pigments we use.

Key Discussion Points and Insights

1. What is Color? Newton vs. Goethe

• Newton’s Experiments (02:00–08:15)

  • At age 23, Newton experimented to uncover the nature of color.
  • He used a prism to show that white light comprises all visible colors.
  • “A colored image of the sun. That’s gorgeous, isn’t it?” — Victoria Finlay (06:25)
  • This finding challenged prior beliefs that prisms added impurities to pure white light.

• Philosophical Pushback

  • John Keats accused Newton of “removing all the poetry from the rainbow.”
  • Goethe observed afterimages (seeing a violet flower shape after looking at a yellow one) and theorized color also arises in the mind.
  • “Maybe our perception of colors began in the world, but maybe it was finished inside the mind.” — Joan Allaire (09:10)
  • Today, scientists and philosophers still debate whether color is objective or a construct of our perception.

2. How Do Other Creatures See Color? (12:00–31:30)

• Humans, Dogs, Birds, and Insects

  • Humans: 3 types of cones (red, green, blue), enabling us to see ~100 color shades.
  • Dogs: Only 2 cones (blue and green) — their perception is like that of a colorblind human; rainbows appear mostly blue, green, yellow (14:00).
  • “That’s a sucky rainbow, dog.” — Robert Krulwich (15:40)
  • Sparrows: See colors from ultraviolet to red, experiencing a broader spectrum (17:00).
  • Butterflies: 5-6 color receptors, seeing even more colors than birds or humans, especially in the blue-green range (19:00).

• Mantis Shrimp: The Superchampion

  • Mantis shrimp have 16 color receptors (21:00).
  • They see multiple kinds of ultraviolet and colors humans cannot imagine.
  • “They have the most complicated visual system of any animals by a factor of two or more.” — Tom Cronin (23:25)
  • Yet, it remains unclear what they actually experience, given their tiny brains (24:50).

3. Changing and Enhancing Human Color Vision (31:30–41:10)

• Colorblindness Cured in Monkeys

  • Jay Neitz engineered monkeys to express a third cone (red), enabling color-blind monkeys to see red after a period of brain adaptation (33:15).
  • “Every day, they would fail… Until one morning, after about 20 weeks… they began to not fail.” — Jay Neitz (36:35)

• Tetrachromacy—Super Color Seers

  • Tetrachromats (typically some women) may have a fourth cone, possibly enabling them to perceive millions of additional color shades.
  • “There are some people who are already a little bit mantis shrimp…” — Jay Neitz (42:15)
  • However, only those whose brains “learn to use” the extra information experience enhanced color perception. Most with the gene don’t use it.

• Testing a Potential Tetrachromat

  • The hosts test a Pittsburgh interior designer suspected to be a tetrachromat; in subtle color tests, she distinguishes between swatches most cannot, yet so does a male artist, suggesting training and attention matter as much as biology (48:55).
  • She describes seeing “so much red, like, up in… the blue sky” (52:10), underscoring subjective differences in color experience.

4. The Dark and Surprising Origins of Pigments (53:30–1:01:15)

• Gamboge: A Cambodian Yellow
  • Pigment “gamboge” is made from tree sap collected over years via bamboo tubes in Cambodia, Vietnam, and Thailand.
  • Story of bullets found in resin—evidence of war in the Killing Fields embedded in the yellow pigment (57:10).
  • “There’s violence in this color.” — Robert Krulwich and Victoria Finlay (1:00:20)
  • This segment juxtaposes the beauty and transcendence of color with their sometimes blood-soaked origins.

5. Color in Language and History (1:01:30–1:38:20)

• Gladstone and the Mystery of “No Blue” in Homer

  • In the Iliad and Odyssey, Homer never uses a word for “blue.” Ancient Greeks may not have had a concept for blue.
  • “Wine-dark sea,” “violet wool,” and “green honey” are some of Homer’s odd color descriptions (1:05:30).
  • Gladstone theorized ancient people were “colorblind”; later, Geiger finds similar patterns across many world cultures.

• The Evolution of Color Terms

  • Red is the first color name after black/white; blue is always last (1:11:20).
  • Rarity of blue dyes and pigments may explain its late arrival in language.

• Do Words for Color Change Perception?

  • The Himba of Namibia lack a word for “blue” and fail to distinguish blue from green in visual tests (1:18:00).
  • “You’re still seeing the blue… You’re just not noticing it. Your eyes are glossing right over it…” — Jules Davidoff (1:21:45)

• Teaching Blue to a Child

  • Linguist Guy Deutscher observes his daughter Alma learning color names, only gradually calling the sky “blue” after associating the word with physical objects, not the “void” of the sky (1:28:30).
  • “Weirdly then, color is a loss of innocence… if we all agree the sky is blue, then that's something we can share.” — Guy Deutscher and Tim Howard (1:37:10)

Notable Quotes & Moments (with Timestamps)

• “Is the light without or is the light within?” — Jim Glick (03:00)
• “He pokes a knife into his eye.” — Jada Moonrod, describing Newton (03:30)
• “The colors were in the light. They are the light.” — Victoria Finlay (08:05)
• “Would aliens see it as red? The answer is almost surely no.” — Mark Changizi (13:50)
• “By adding one photopigment, instead of adding just one more color, you actually add about 98 colors or so.” — Jay Neitz (18:45)
• “They have the most complicated visual system of any animals.” — Tom Cronin on mantis shrimp (23:25)
• “We could cure colorblindness in a human with exactly this technique.” — Jay Neitz (39:10)
• “There are some people who are already a little bit mantis shrimp.” — Jay Neitz (42:15)
• “Do you see some of the pink in the blue? See, I see a lot of pink, like among the blue…” — Susan Hogan, potential tetrachromat (52:10)
• “It is a perfect yellow.” — George Kramer, describing gamboge (1:00:57)
• “The wine dark sea… But the other thing he calls wine color are oxen.” — Tim Howard, on Homer’s color descriptions (1:06:40)
• “If you don’t have a word for blue, blue doesn’t jump out at you.” — Jules Davidoff (1:21:45)
• “Weirdly then, color is a loss of innocence.” — Tim Howard (1:37:10)

Important Segment Timestamps

• Newton and Color’s Physicality: 02:00–09:30
• Color Perception Across Species: 12:00–31:30
• Enhancing Human Color Vision: 31:30–41:10
• Pigments: Gamboge & Their Dark Origins: 53:30–1:01:15
• Color Terms in Ancient Literature: 1:01:30–1:16:00
• Language and Color Perception (Himba Tribe study): 1:16:00–1:22:30
• Learning the Color Blue (Linguist’s Daughter): 1:28:30–1:38:10

Tone and Style

• Curious, Playful, and Philosophical
  The hosts mix awe and fun curiosity with deep, sometimes heavy reflection. The episode weaves science, history, and personal anecdotes with sound-rich storytelling and music, making complex ideas accessible and engaging.

Conclusion

“Colors” surfaces the complexity and wonder of something we think of as simple and everyday. The episode reveals that color is created by physics, biology, language, and culture—all overlapping in surprising ways. Whether discussing the poetry and violence that can be embedded in a single shade of yellow, marveling at animals who see worlds beyond our imagination, or pondering why the sky is blue, Radiolab’s “Colors” episode is a vibrant journey into the heart of human perception.