In the animal world, the ability to multi-task is a matter of life and death. Many species must be ever-watchful for food, while simultaneously looking out for predators who would view them in the same way Like too many open applications that slow down a computer, these multiple tasks compete for the brain’s finite resources. Those who survive life’s challenges are those with an edge at efficiently dealing with multiple demands.

One way of doing this is to use parallel processing – to delegate different parts of a problem to different pieces of hardware. This is exactly the situation found in the human brain, with two asymmetric hemispheres associated with different mental abilities. And this ‘lateralisation’ is not unique to us, but seems to be present in all back-boned animals, from fish to apes. An explanation for this asymmetry now becomes obvious – it may allow animals to multi-task, acting as a sort of cerebral division of labour.
…
In these cases, regardless of parallel processing power, an asymmetric brain is clearly a disadvantage. The two scientists believe that the tipping point between these pros and cons comes when an animal has to perform difficult mental tasks.

Other studies have shown that asymmetrical brains endow wild chimpanzees with superior termite-fishing skills, and (equally wild) human children with better mathematical and verbal abilities than their classmates. It may be that over the course of evolution, our brain’s halves started to work together more effectively as they became more different and specialised. It is ironic and sad then, that the opposite seems to hold true for the divergence of human cultures.