What’s a brain even for?

Dear reader, I must word a short confession before getting into the meat of todays post. It has, I admit, been a matter of months since my last appreciable blog instalment. I can’t pretend I haven’t had some time to spare of a weekend to pen a few lines. Nor, as a psychology student, can I say I’ve had little incentive to write. No, paradoxically enough, what really impeded my pen was the vast amount I could write about.

After sitting down multiple times to settle on just one appropriate theme, it eventually occurred to me that I’d never truly explored something so fundamental as the reason we have brains in the first place. I mean sure, a hypothetical body that…didn’t wake up, without a brain and associated nervous system, wouldn’t take long to turn to stardust. As renowned philosopher Daniel Dennett once observed, a brain transplantation is the only such operation in which one would want to be the donor, not the recipient. Unlike the heart, kidneys and other vital organs of the human body, the brain gives rise to much more than human life, it gives rise to our very essence. But what, exactly, did we evolve such an all-important organ for? Considering  certain insects, jelly-fish and multiple other living organisms get along just fine without any nervous system at all, what does the brain add to an animal’s survival? In short, the answer is movement. The main purpose of the brain is too allow for movement in the environment in a meaningful way. Consider the classic example of the sea squirt. This sea creature is born with a simple nervous system which functions to coordinate movements as well as a rudimentary eye spot with which to “see”. The sea squirt spends its early days swimming about searching for a place in which to attach itself and settle forever. As soon as it has found a suitable home however, the squirt promptly digests its nervous system, brain and all. In essence, the squirt no longer needs to move and so no longer needs a brain to coordinate its motion.

The humble sea-squirt, quietly eating itself.

Throughout human evolution the brain has allowed for adaptive movement in highly dynamic environments. It has allowed us to formulate the likelihood of achieving a specific goal given certain motions and enabled us to weigh up the pros and cons of acting in a certain way. As the hominin species evolved and began to move through increasingly diverse environments, the human brain also evolved allowing for more adaptive and useful movements within a given niche. The human brain can now do many more tricks than move and interact within its environment. Through exceptionally complex electrochemical networks the modern Homo sapien brain can engage in what are known as “higher-order” cognitive processes. Through these higher-order connections we humans can think abstract thoughts, memorise strings of meaningless numbers, imagine what-if scenarios from the past and even contemplate our very existence. In a future post I’ll take a look through evolution at how it is the interaction between perceptual processes within the brain and action upon the environment may have brought about such complexity of activity within a single mass of layered, convoluted matter. Until then however I urge you to appreciate your ability to move and adapt under different circumstances. It is movement you must thank for having a brain at all, and it is your brain you have to thank for your ability to move. Without either it’s very likely you’d be attached to a rock somewhere, digesting your innards.