Idle Minds and What They May Say about Intelligence

It turns out that cultivating an active idle mind might actually encourage a higher IQ.

In essence, they suggest that in smart people, distant areas of the brain communicate with each other more robustly than in less smart people.

In a recent paper, researchers at the Chinese Academy of Sciences, led by Ming Song, examined how resting brain networks differ between people who have superior versus average IQ scores. They used graph theory to quantify the network properties of the brain, such as how strong the communication is among distant brain regions. A graph is a mathematical representation that is composed of nodes (or brain regions) and connections between them (functional connectivity or temporal correlations), and can be used to characterize neural networks. Like prior researchers, they found that the posterior cingulate cortex is the hub of the human brain – it is the most widely and intensively connected region of the human brain at rest.  Moreover, the strength of connectivity among distant brain regions was greater in people with superior than average IQ scores. Another 2009 study came to a similar conclusion, and noted that the strongest relations between resting connectivity and IQ were observed in the frontal and parietal brain regions, which have been most associated with performance on IQ tests.

Thus, remarkably, the strength of long-distance connections in the resting brain can be related to performance on IQ tests.  We are often impressed when people make creative connections between ideas – perhaps long-range connectivity in the brain empowers such mental range.

These “at rest” findings fit well into what we know of how intelligence develops in children. Previous work discovered that in typical brain development there is a progression from local to distributed network connectivity.  In children, there is strong local connection and weak distant connection. That changes with age:  local connectivity decreases and long-distance connectivity increases.  Intelligence by almost any measure increases with age until young adulthood.  Interestingly, Earlier research also found that slower thinning of the neocortex (often interpreted as pruning of synapses) was associated with higher IQs in children; perhaps the slower pruning allowed for the establishment of long-lasting long-distance connections.  Thus, the strength of long-distance connections in the brain may support the growth of intelligence and influence variation in adult intelligence.

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