Read more: "Mind maths: Five laws that rule the brain"
If you stretched out all the nerve fibres in the brain, they would wrap four times around the globe. Crammed into the skull, this wiring looks like a tangled mess, but in fact mathematicians know its structure well - it is a form of the "small-world network".
The hallmark of a small-world network is the relatively short path between any two nodes. You've probably already heard of the famous "six degrees of separation" between you and anyone else in the world, which reflects the small-world structure of human societies. The average number of steps between any two brain regions is similarly small, and slight variations in this interconnectivity have been linked to measures of intelligence.
That may be because a small-world structure makes communication between different areas of a network rapid and efficient. Relatively few long-range connections ...
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