Purple blooms in Thailand’s parks and markets—from the delicate dok bua (lotus flowers) that decorate temple altars to vibrant mangosteens stacked in fruit stalls. Yet behind its abundant physical presence, cutting-edge neuroscience research is challenging what we think we know about purple itself. Is it possible that the color so cherished in art, fashion, and Buddhist symbolism is really an invention of the human brain? Recent findings, highlighted by neuroscientists and art historians, reveal that purple may be less concrete in nature than it appears, calling into question not only the color’s existence, but the very essence of how Thai people (and all humans) experience the world of color.
Around the world, purple often signifies wealth, power, and spiritual richness, qualities deeply woven into Thai royal and religious traditions. Yet, as explained in a June 2025 Live Science report, purple is curiously absent from the visible-light segment of the electromagnetic spectrum—unlike true hues such as red, yellow, or blue, which have their own unique wavelengths (Live Science). In scientific terms, purple is classified as a “nonspectral” color: it cannot be produced by a single wavelength of light. Instead, it emerges when our eyes and brain combine both the shortest (blue) and longest (red) light waves, essentially constructing purple in our perception, rather than directly from nature. Dr. Zab Johnson, executive director and senior fellow at the Wharton Neuroscience Initiative at the University of Pennsylvania, notes, “I would actually say that none of color actually exists. It’s all the process of our neural machinery, and that’s sort of both the beauty and the complexity of it all at the same time.”
This brain-based view of color upends centuries of straightforward thinking. Color, as we experience it, isn’t a property of objects or light alone—but an active interpretation by our own visual system. When sunlight strikes an object—a dazzling amethyst, perhaps—the surface absorbs some wavelengths and reflects others. These reflections strike the eye’s three kinds of specialized cone cells, each tuned to either long (red), medium (green), or short (blue) wavelengths. The signals from these cones are sent as electrical impulses to the brain, which “computes” color by weighing the signals received.
When it comes to familiar spectral hues, the process is direct. If mid- and short-wavelength cones are both triggered, the brain perceives teal; activating only the long-wavelength cones yields red. But purple defies this simplicity. There’s no “purple” wavelength for the cones to register; there are only blue and red, which sit on opposite ends of the visible spectrum. When these are sensed together, the brain invents purple—a color that has no corresponding single light wave. In essence, purple as you see it doesn’t exist in the external world; it is conjured entirely by your mind. As Dr. Johnson observes, the brain “bends this linear visible spectrum into a circle,” making purple seem as real as any other color, even though light itself doesn’t contain it.
This revelation has far-reaching implications in science, philosophy, and everyday life. For centuries, purple’s rarity was celebrated across ancient civilizations, including Thailand’s own royal courts, where purple dyes were signs of status and spirituality. According to Narayan Khandekar, director of the Straus Center for Conservation and Technical Studies at Harvard Art Museums, ancient Phoenicians even extracted Tyrian purple from sea snails, a laborious process reserved for the elite. Thai culture mirrored this value, reserving purple for ceremonies and monk’s vestments. “It doesn’t really exist in nature. And so when you can create it, it has this extra value,” reflected Dr. Johnson. This historical reverence persists in Thai society today—witness purple banners during royal anniversaries or violet sashes during Buddhist ordinations.
For science educators and students in Thailand, these findings offer new ways to engage with color theory—challenging rote learning and encouraging curiosity about how biology, physics, and culture intertwine. School curricula may soon incorporate the neuroscience of vision, moving beyond textbooks describing colors merely as wavelengths. Museums, art teachers, and digital designers will need to rethink how they present color—acknowledging purple’s unique status as a feat of perception, not physics.
Experts also hint at wider implications for how Thais experience reality in an era saturated with digital screens, where colors are created by mixing tiny dots of red, green, and blue light (not purple). As digital immersion grows, understanding how the brain interprets blended colors can help guard against visual fatigue and enhance accessibility for people with color vision deficiencies—a significant public health issue in Thailand.
How might this science influence future Thai society? As the nation continues to invest in STEM education and innovation, the story of purple’s “unreal” reality can serve as a powerful metaphor for critical thinking and creativity. It’s a lesson in questioning assumptions, respecting the mysteries of perception, and ultimately, finding beauty in what the mind alone can create. It also opens discussion on how culture preserves the meaning of what science deems as “illusory”—a symbol of how human experience is as valuable as hard data.
For everyday readers, the latest research encourages a new mindfulness about color in daily life. Whether enjoying the spectacle of Songkran flower parades, selecting fruits at the market, or appreciating traditional Thai silk, remember: purple exists not as a wavelength, but as an ongoing collaboration between your eyes, your brain, and your culture. The practical takeaway? Embrace curiosity about your own perception—by learning about vision, supporting inclusive design for those with color blindness, and celebrating the unique cultural stories that transform science into wonder.
For those keen to explore further, resources include the original Live Science report, the Wharton Neuroscience Initiative, and the Straus Center for Conservation and Technical Studies. Thai museums and universities are also beginning to translate such neuroscience into exhibitions and lesson plans, providing opportunities for families and students to discover the mind-bending world of color.