Neuroscientists keep trying to unlock the mystery of what sparks visionary thinking and artistic invention.

It was 60 years ago, at the start of his career, but the architect and educator John P. Eberhard remembers the very moment the idea came to him for what would be his seminal creation: the modular church. He’d been approached to design a chapel for a new congregation in Champaign-Urbana—a kind of starter church that could be erected quickly, disassembled, and moved when the congregation outgrew it. “I remember having ideas roll around in my head about what it could be,” Eberhard recalls. “I remember when I got the big idea: visiting my parents, sitting in their bedroom, rocking in a rocker. All of a sudden, into my head came this whole idea of designing a chapel out of wood panels bolted together, with equilateral trusses, two-by-twelves with split-ring connectors, four-by-eight plywood panels. The whole idea was there.”

Out of that flash of insight came a business— Creative Buildings, Inc., which in the 1950s sold more than 100 prefab churches around the country—and a lifelong interest in the nature of creativity by Eberhard, former chair of the School of Architecture at Carnegie Mellon. His account of an idea’s arriving, fully formed, seemingly out of nowhere, corresponds closely with how at least one classical musician approached composing. While walking or resting, he wrote, melodies would come into his mind “whence and how, I know not,” taking root and growing until the piece “stands almost complete and finished in my mind, so that I can survey it, like a fine picture or a beautiful statue, at a glance.” The composer was Mozart.

Separated by hundreds of years and the gap between a successful professional and a world renowned genius, they describe in almost identical terms one of the most sublime and elusive events in human experience, the “eureka moment” of creativity. It has tantalized philosophers and poets, who imagined it could only come directly from God—Ibsen spoke of receiving “the spark of the divine fire”—and more recently scientists, who have begun looking for objective correlates to creativity in the brain, just as they do for perception, movement, and memory.

But they haven’t gotten all that far, according to Nancy Andreasen, author of The Creating Brain: The Neuroscience of Genius (2005). Nineteenth-century theorizing that linked creativity to traits such as left-handedness and stammering haven’t been borne out, and neither has the left-brain/right-brain distinction (the one on the right was the part you were supposed to use in artistic ventures) that sold so many magazines in the 1980s. Even the common-sense assumption that originality correlates directly with intelligence has been debunked: the consensus today is that success in a creative field requires a threshold IQ of around 120—equivalent to about the 90th percentile—but, beyond that, you don’t have to be an Einstein to be Einstein. One problem, Andreasen notes, is that modern neuroscience relies heavily on putting subjects in MRI machines that measure activation in different regions of the brain under specific conditions, but, once you get them in there, how do you detect creativity? Wait for them to compose a symphony or design a building in their heads?

Andreasen has done some of this research herself; as a neuroscientist at the University of Iowa, she is particularly well situated for it, since the Iowa Writers’ Workshop attracts a steady stream of poets and novelists to the campus, a resource she has been supplementing with visual artists whenever she can lure one. (She hasn’t had the chance to study an architect yet; anyone reading this with a few days to spare in Iowa can give her a call.) Her early work used stratagems to elicit creative activity, such as giving people five words and asking them to write a story around them. She decided it was a waste of time: the task didn’t engage them sufficiently; it activated regions of the brain involved in language processing, which didn’t seem to capture anything unique about the creative effort.

Eventually she concluded that there is no dedicated area for creativity in the brain, in the way that, say, the prefrontal cortex handles the planning and decision-making processes neuroscientists call “executive function.” Creativity is a function of forging relationships and making connections; it is a way of thinking in metaphors that cut across not just the psychological borders of the mind but the physiological boundaries of the regions of the brain. V.S. Ramachandran, a pioneering neuroscientist at Cambridge University, discovered that artists, poets, and novelists have seven times the normal incidence of synesthesia—the peculiar phenomenon in which one form of sensation (hearing a passage of music, for instance) is experienced as another (a particular color or smell). In The Architect’s Brain: Neuroscience, Creativity and Architecture (2009), Harry Mallgrave relates this finding to architecture, quoting a disciple of the late Venetian architect Carlo Scarpa, who believed he “worked entirely through a synesthetic process that entailed, on the same pages of sketches, different colors and styles of drawing with different media. It was through these ‘bundles of intertwined sensory perceptions’ … that Scarpa was able to modulate his multisensory ideas—say, red of a waxy pencil from the red of a brick from an identical red of India ink.”

The parts of the brain that seem to show more activity in creative people (compared to Andreasen’s control subjects) are the “association cortices,” regions that are markedly more developed in humans than other animals and also among the last to mature, continuing to develop into the early 20s. Their function is to process the output of the primary sensory areas, identify phenomena, and make connections among them. How do we see a face? The retina receives light and transmits nerve impulses; the primary visual cortex resolves these into a form, with shape and color; the visual association cortex recognizes and categorizes it and compares it to a summer’s day.

And it is these areas, Andreasen found, that are most active during the condition she describes as “randomly wandering unconscious free association”— the condition described by Eberhard, rocking quietly in his parents’ bedroom, Mozart strolling through the streets of Salzburg, or the 19th-century chemist August Kekule dozing off in front of the fire and waking with the structure of the benzene molecule dancing in front of his eyes.

Of course, dozing by itself isn’t enough to guarantee immortality. The eureka moment, as described by Andreasen and others, is only the third of four steps in a creative process: preparation—acquiring the basic background knowledge to make a contribution to a field; incubation—trying out various ideas and approaches; insight— the sudden apprehension of a solution; and production—putting the idea into practice. Naturally, insight gets most of the attention from researchers, and it’s the part that aspiring artists tend to focus on, as having the highest ratio of psychic reward to effort.

But even Mozart needed to study and practice, despite his phenomenal and precocious natural gifts. In fields less abstract than music—such as physics or architecture—that is especially true: almost any idea in science, however original, must at least partially fit into the framework of existing knowledge, and a building has to stand up. “Creativity is a process of focusing on something with discipline, of training the brain to think while working,” says Mallgrave. Faced with a difficult problem, “we sleep on it, take a shower, and suddenly we have an answer to where to put that door.”

Ah, yes, the eureka moment, the idea flitting at the edge of our consciousness, just beyond our apprehension. It will come to us when we are prepared to receive it—though it often comes with a price; the idea that creativity bears a relationship to mental illness is not without foundation, says Andreasen. The characteristic affliction is mood disorder, which she finds extremely common among the writers and artists she has studied, in their siblings and offspring, and in the historical record. Among her first subjects was Kurt Vonnegut, who suffered from depression, and whose immediate family had both a high incidence of mental illness and creativity in numerous fields. (His father was a successful architect.)

And there is at least a metaphoric connection, if not a definitive statistical one, between creativity and schizophrenia, both of which involve a state in which mental lines break down and free association reigns. Researchers at Berkeley back in the 1950s and ’60s administered the standard test of mental health, the MMPI, to writers and architects who were considered especially creative and found they scored suspiciously high on the scales of schizophrenia and paranoia. But, as the Harvard psychologist Shelley Carson points out, in an essay with the provocative title “Creativity and Psychopathology,” that reflects a tendency, not an actual diagnosis. Patent schizophrenia is incompatible with productive work in most fields, especially those whose end products have to meet safety and fire codes. The other mental state characterized by hyper-free association is, of course, the one we enter into when we take drugs. Perhaps the most celebrated eureka moment in history was the opium-induced dream of Samuel Taylor Coleridge, out of which came the psychedelic thunderstorm of the opening stanzas of “Kubla Khan.” It was a dream, of course, about architecture.