A caveat: The discovery of neurobiological correlates of IQ cannot be construed as evidence that IQ is determined by genes and fixed at birth. Most research favors the view that IQ scores are influenced both by genes and experience (like almost all human traits). Further, recent behavioral research has show that intensive training with adults can increase IQ-type scores.
These intriguing findings on intelligence are only the latest to emerge from the new strategy of using the resting mind to help discover the functional organization of the human brain. Early reports of such resting brain activity around 1995 were viewed skeptically, but many findings since 2000 that relate well to other kinds of neuroscience knowledge have made the study of resting-brain connectivity an exciting research area, in subjects ranging from human infants to primates. In at-rest studies, children or patients do not have to perform complex tasks (or any tasks). So at-rest scans are proving useful for a wide range of studies examining development and clinical disorders. Indeed, many researchers are now mining old data sets with resting periods from scanning sessions, retroactively transforming a modest control condition into a cutting-edge brain analysis. Moreover, because resting scans involve no specific task, they are readily pooled across sites into large data bases.
Already, striking differences have been observed in the patterns of resting connectivity found in autism and schizophrenia. People with autism exhibit reduced connectivity in the brain network most associated with introspection. That lower connectivity may reflect their reduced ability to focus on their own thoughts and feelings, and reduced appreciation of the inner mental worlds of others. In contrast, people with schizophrenia have exaggerated connectivity in this network. This could reflect problems of self-reference and paranoia in schizophrenia, with an overactive network encouraging patients to interpret events in their environment as having special relevance to themselves. Characteristic changes in the resting brain have been found also in depression and Alzheimer’s disease, raising the possibility that resting-brain scans may help with diagnoses.
Beyond disease, and beyond IQ, these exciting discoveries about the resting human brain raise the question of whether we are gaining the novel capacity to measure quantitatively our most intimate and unique inner selves. Are you most “you” when you’re racing through work? Or when you’re simply sitting in a chair, mind adrift, just being?