BRAINGLOW is the visual adornment of a cartoon brain — usually represented as a disembodied organ — with an outward-radiating illumination-of-sorts. Brainglow doesn’t exist in nature, of course. Brains don’t literally glow blue-green. But you’d never know it from the pictures of brains you’re likely to encounter walking through a bookstore or surfing the internet these days. You see brainglow everywhere — dust jackets, glossy conference brochures, websites promising heightened brain power.
It seems like an obvious statement to make, but brains don’t actually glow. It’s a pictorial device — like a halo — signifying a certain esteem we have for the brain, a certain awe. Or maybe the image of a glowing brain captures a kind of feeling we feel when we think. But an actual saint’s head doesn’t glow, and an actual brain doesn’t glow either, no matter what our brain scans say. Brainglow isn’t neuroanatomical. Brainglow is metaphorical.
It’s not that I’m not awed by brains or brainpower. I am. It’s just that the ubiquity of brainglow distorts our understanding of brains. Specifically, brainglow suggests that there is a pathway from the substance of the brain outward through the skull into the atmosphere around the brain and the head. Brainglow also suggests, perhaps unwittingly, that this outward-radiating pathway is how brains do what they do, that brains function by glowing or by emitting something like light.
Of course, such outward-radiating pathways exist. Brains do emit things. For example, brains emit electromagnetic radiation — heat, electrical activity, magnetic fields — which can be detected and very precisely characterized. But brains don’t work by emitting electromagnetic radiation. Brains don’t work by emitting anything for that matter.
A brain works in concert with a nervous system which it sits atop. The important pathway there happens at the bottom of the brain — the brain stem — downward through the spinal cord and out through the sense organs. And a parallel pathway from the sense organs into the spinal cord and up toward the brain. If the brain points anywhere it points down into the body, and the body points up into the brain.
In other words, brains do glow, in the sense that they radiate heat and characteristic electrical patterns, but brains don’t work by glowing. Brains don’t function by projecting anything whatsoever outward from their curly surfaces. No such functional neurological pathways exist. It’s not like we communicate with each other brainwave-to-brainwave. Wisdom doesn’t ooze from the brain like a mysterious perfume of light rays.
Indeed, most common depictions of the thinking brain — a brain or a head with a light bulb over it, thought bubbles, the brain as an interior cinema — emphasize the brainglow pathway, despite its factual inaccuracy, and de-emphasize the brain-body axis and the central role of the sense organs, perpetuating the false idea that the mind is a kind of brain-perfume.
Having a great idea may feel like a light bulb glowing, or like a thought bubble blossoming, but that’s not how it goes down anatomically.