As most people know, different parts of the brain are assigned different tasks. The brain is lateralized – asymmetrical, by design. And, there is a very good reason for that. The split-brain design allows us to process many things at once. We owe our ability to multi-task to the hemispheric design of the brain.
Like the human brain, many modern computers are coming with essentially 2 hemispheres, or Dual Core processors. When one processor is busy checking email, the other can be scanning for viruses. This is analogous to how brain hemispheres work.
To test the theory of the split-brain advantage, Aneglo Bisazza and Marco Dadda of the University of Padova bred two different strains of the same species of fish. One strain was bred to have asymmetrical brains like most vertebrates, and the other strain was bred with symmetrical ones (both sides processing the same thing).
Both fish groups could handle a single task equally well, such as catching shrimp. But, if a second component was added to the mix – a predator – the split-brain advantage became quite apparent. The symmetrical-brained fish took twice as long to catch their prey, having to divide their attention between watching for prey and catching a meal. Their asymmetrical cousins, on the other hand, were able to focus on both tasks at once, and the introduction of a predator hardly affected their ability to catch food at all.
Asymmetry is absolutely essential in order to complete the complex tasks we take for granted. In a conversation with someone, the left brain will be processing the verbal language, while the right brain interprets tone and inflection. If you are asked to imagine a scene, the left brain will create the details, while the right brain handles the overall shapes, sizes and their spatial locations. Without both sides processing all of these details at once, we would never be able to function at the advanced level we do.
But there are also disadvantages to asymmetry. Certain tasks may be easier to execute on either the left or right side of your body. The left side of the human face tends to be more expressive because it is controlled by the right hemisphere. Most people are right-handed because the left brain is usually dominant. According to Bisazza and Dadda, the aforementioned fish will tend to guard one side of their body over the other and as a result their predators will tend to approach them from the unguarded side.
Brain asymmetry means that both hemispheres have to work closely to ensure a smooth ride, and having an overly dominant hemisphere is invariably a bad thing. Brain damage to the right hemisphere can leave a person indifferent and uncaring, while brain damage to the left can leave them with severe depression, or without speech.
You’ve probably heard quite a lot about “hemispheric synchronization” already (just look at how many brain stimulation companies have “sync” in their names). The word synchronization can be misleading in the context of the brain, since it implies that the two halves are processing information in the same way, which isn’t usually the case. However, brain activity can be more evenly distributed across both hemispheres. In a healthy, intelligent brain, the two halves are communicating fluently, and working closely together. There is a reduction in dominance of one hemisphere over another.
To see for yourself the manifestation of hemisphere-specific neural processing, check out the below video to see what happens when the corpus callosum, which facilities cross-hemisphere communication, is severed: