Science may have found the home of humanity’s most distinctive trait: imagination.
That “home” is actually a network all over the brain, supporting the idea that imagination and other key cognitive processes are born in a “mental workspace” of many neural regions firing together, not isolated regions firing alone, according to a new Proceedings of the National Academy of Science (PNAS) study.
The study is attracting attention.
“An interesting advance on existing research developments,” says Bernard Baars, a pioneer of the “mental workspace” theory, and former Senior Fellow at the La Jolla Neurosciences Institute. He was not involved in the study.
“A terrific article,” says Georgetown University neuroscientist Adam Green, who studies neural correlates of analogical reasoning, and who was also uninvolved.
“We have gone through an era where we have been fascinated at seeing how various areas of the brain are activated in perceptual and cognitive processes,” says the University of California, Santa Barbara’s Michael Gazzaniga, viewed by many as founder of cognitive neuroscience. Gazzaniga edited the PNAS paper. “Using the new tools of network science, the authors are beginning to map out how the multiple areas interact to produce human cognition.”
In the study, subjects were placed in an fMRI. Different brain networks lit up when they were asked to simply visualize an abstract form, versus when they were asked to create or dismantle one. The ability to manipulate mental images is a key human trait, scientists have long thought.
“The human ability to flexibly combine, break apart, and otherwise modify mental images, symbols, or other ideas or concepts, seems to be central to many of our creative behaviors like the creation of art, scientific, or mathematical thought,” says Dartmouth College neuroscience graduate student Alexander Schlegel. Schlegel, with Dartmouth cognitive neuroscience professor Peter Tse, led the PNAS study. “Our lab is very interested in how the brain can do this. So in this study we asked: `How does the brain manipulate mental images?’”
To study this, “while in an fMRI scan, participants were asked to either imagine specific simple, abstract shapes, or to mentally combine them/break them apart. We found a widespread network of areas in the brain responsible for making the latter manipulations of imagery happen. This network resembles a ‘mental workspace’ that scholars theorize may be at the core of many high-level cognitive abilities that distinguish humans from other animals.”
The networks that light up during such tasks are not “states,” Schlegel cautions, as if “the brain adopts static postures. It doesn’t. That is like asking how the state of a waltz differs from the state of a salsa dance. The brain is a dynamic process.”
That said: “We saw differences in brain activity levels between the `manipulate’ and `maintain’ conditions.” There were no differences in activity levels between the two “manipulation” tasks, but “patterns of activity in several brain regions changed between the two manipulation tasks.”
Says Green: “The frontal and parietal brain regions targeted in this work are known to contribute to intelligent and creative cognition across different tasks and modalities. The type of working memory maintenance and manipulation task used in this work has been repeatedly associated with these brain regions in the fMRI literature. What's new and encouraging about this work is that the authors build on that solid foundation of "where" findings in the fMRI literature, to ask a "how" question. The brain areas in this study, and the type of cognitive task used, do not encapsulate all elements of creativity or intelligence. No single study could. But the neurocognitive operations investigated are likely necessary, if not entirely sufficient, for a great deal of intelligent cognition, so beginning to explicate the mechanistic dynamics of these operations adds real value to our present understanding.”
The study unveils "the physical evolution of thought processes," says University of Montana neurologist Charlie Gray, who showed in Science that visual memory involves synchronized brain waves. "Exciting."
Why has Schlegel’s approach not been tried before? The fMRi –and analytical techniques used – are fairly new. Also: “The field still thinks more in terms of `mental representations’—like brain states—than `mental processes,’” Schlegel says. “If your questions revolve around finding out how the brain represents this or that in a static fashion, you tend not to ask questions about how the brain transforms information over time.”
Also: “Until recently, it has been fairly taboo in psychology to study mental phenomena (consciousness, imagery, creativity). These couldn’t be directly observed, so were off limits to scientific study. Behaviorism came out of this. Its effects are still present. To some degree the idea of a `mental workspace’ doesn’t fit with models many researchers use when thinking about the organization of the brain.”
“I like the very rapid developments in consciousness science,” agrees Baars. “In the last ten years there has been an amazing wave of excellent brain studies, psychological experiments, and modeling efforts. Consciousness is a rich subject. Until recently it was a taboo in the sciences. But we now can actually look at signaling in the living brain, and make sensible predictions. All this is amazing after years of scientific neglect.”