University of Notre Dame researchers report evidence that general intelligence is associated with how efficiently and flexibly brain networks coordinate across the whole connectome, rather than being localized to a single “smart” region. The findings, published in Nature Communications, are based on neuroimaging and cognitive data from 831 Human Connectome Project participants and an additional 145 adults from the INSIGHT Study.
For decades, neuroscientists have linked functions such as attention, perception, memory, language and reasoning to specialized brain networks, often studying those systems in isolation. But that approach leaves a central question unresolved: how a unified mind emerges from many specialized parts.
“Neuroscience has been very successful at explaining what particular networks do, but much less successful at explaining how a single, coherent mind emerges from their interaction,” said Aron K. Barbey, the Andrew J. McKenna Family Professor of Psychology at the University of Notre Dame.
A team led by Notre Dame graduate student Ramsey R. Wilcox set out to test predictions from the Network Neuroscience Theory, a framework that argues general intelligence (often called “g”) reflects coordinated activity across the brain’s global network architecture rather than the output of any single brain region.
To evaluate that idea, the researchers analyzed brain imaging and cognitive performance data from 831 adults in the Human Connectome Project. They also examined an independent sample of 145 adults in the INSIGHT Study. By jointly modeling measures of brain structure and intrinsic functional patterns, the team assessed large-scale features of how the brain is organized.
The study reported evidence consistent with four core predictions of the theory: that general intelligence (1) engages multiple networks rather than a single network, supporting distributed processing; (2) depends in part on weak, long-range connections that promote efficient global coordination; (3) involves regions that help orchestrate interactions among networks, guiding information flow; and (4) is associated with a small-world network architecture that balances local clustering with short communication paths across the brain.
“We found evidence for system-wide coordination in the brain that is both robust and adaptable,” Wilcox said, adding that such coordination helps set the range of cognitive operations the system can support rather than being tied to any one task.
Barbey said the results argue for a shift away from strictly localist accounts of intelligence. “General intelligence becomes visible when cognition is coordinated,” he said, “when many processes must work together under system-level constraints.”
The paper lists Babak Hemmatian and Lav R. Varshney of Stony Brook University as co-authors.
The researchers also said the findings could inform broader questions about brain development, aging and the effects of diffuse brain injury—cases where large-scale coordination across networks may change. They further suggested the work may have relevance for artificial intelligence research by highlighting system-level organization, not only the scaling of specialized capabilities, as a potential ingredient in more flexible, general-purpose performance.
“Many AI systems can perform specific tasks very well, but they still struggle to apply what they know across different situations,” Barbey said.
