The Purpose of the Brain

The lowly sea squirt is a primitive ancestor of ours with a peculiar story to tell. Consisting of a rudimentary brain, visual system, and notochord, the sea squirt spends its early life gliding through the depths of the ocean in search of a stationary object to call its home. Once it finds a suitable location, it attaches itself and will remain in place for the rest of its life. Upon the capstone of realization that it has no need to move again, the sea squirt performs an act so bizarre that it should jolt the pillars supporting our understanding of human cognition; it digests its own brain along with all remains of its humble nervous system.  Once the brain no longer needs to perform movements, it becomes a useless commodity to the organism. Rather than letting it remain dormant, natural selection has gifted the squirt with methods to use the nervous system as a digestive energy source. The behavior and anatomy of this animal evokes no controversy when determining the purpose of its brain; existing solely to produce complex movements for survival.

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That last statement is a tough metaphorical pill to swallow.  Fortunately, the brain of one particular type of primate evolved for a different reason.  Of the ~9 million species living on the Earth, humans alone carry a brain with exuberant abilities that cannot be explained by using the minimalistic motor theory. We can describe all other organisms and objects in a simple way, but the human brain must be of a divine complexity; out of our understanding. We are different from the uncivilized animals of nature, right?  Wrong. These fictitious beliefs that have taken hold in our society are not objective physical mechanisms that explain human behavior, they are nothing more than the hopeful dreams of a human brain that has realized it may suffer the same destiny as the lowly animals that wander beneath it.


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As brought forth by Richard Dawkins in, The Selfish Gene, evidence is piling up that organisms, no matter the complexity, are survival machines elegantly designed by natural selection to outperform all in a race to reproductive success. Organisms particularly needs to produce more complex movements than its competitors to achieve a reward of survival, and hopefully reproduction. To do this, the brain must evolve mechanisms to not only remain unpredictable, but also to anticipate every action that is selected by other organisms; it has knack for predicting the actions of others before they are even initiated.  In comparison to the sea squirt’s primitive nervous system, the human brain is transcendent.  Containing two independent, interconnected hemispheres layered with roughly one trillion processing nodes (neurons), this structure would rarely be compared to an animal as simple as the sea squirt. The large gap in mental processing skills between humans and all other species consistently raises suspicion of a divine origin, yet this collection of shiny attributes is proving to be nothing more than a red herring. Recent research shows that the neocortex—thought to elevate us beyond the mental processing of other species—is modulated by the motor centers of the brain.  Unfortunately, many researchers in the cognitive sciences continue to compulsively strive for an alternative explanation of higher order cognition, based on concepts of meta cognition and mind rather than neurophysiology and behavior. It is difficult to accept an explanation the simple sea squirt provides with such clarity; the brain is a designed to produce adaptable movement.

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Cognitive explanations of the mind are based on the notion that the enlargement of the cerebral neocortex during evolution holds the secret of humans’ mental abilities, specifically the prefrontal regions. The advancement of the neocortex in mammals has been a great platform for cognitive scientists to begin developing new concepts, such as social cognition, language acquisition, and more recently, mind shaping. However, recent research has shown that the motor center (the cerebellum) in our brain modulates these cognitive regions (Click for article – Cerebellar networks with cortex). This places our understanding of the mind in a tricky predicament. If the motor brain is in charge of running cognitive systems, then what do we make of advanced traits of social cognition in humans? If we glance back to the morbid behavior seen by the sea quirt, then we must conclude that language, love, thinking, social behavior, and all other cognitive processes must exist to serve our motor brain and its methods of creating adaptable movement.

The neocortex did not create the superior ability of humans, yet because it is the specific location where we differ most from other animals, it is viewed in a divine light. This argument can be countered when we do not bias the expansion of the neocortex, and observe other brain areas that expanded with it. For example, it was recently found that not only did the neocortex expand to great proportions in humans, but the cerebellum followed in concert with it (Click for article – Rapid evolution of the cerebellum).

cerebellum and neo

This can be explained by the motor brain needing a way to perform more complex movement sequences. As a solution, evolution of the motor brain drove the expansion of the neocortex, allowing for multiple mediating stations for information processing modularity (including the neocortex), and excessive feedback loops that excel in monitoring, anticipating, and planning complex movement sequences. Greater association networks in animals who retained a larger neocortex throughout phylogeny were able to create more unpredictable behavioral responses when facing predators or competitors. This logic becomes undeniable if we keep in mind that the brain is able to affect and interact with the environment in only one way, through movement behavior. A restructuring of the way we observe and explain social and neural processes will soon prove to be inevitable based on this fact. If we adopt the movement perspective and examine the brain through an “motor lens,” it will not degrade our human values, but simply allow for a mechanistic and testable way to understand how our abilities operate, and possibly provide evidence to build a proper foundation for current theories proposed by cognitive scientists.





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