The Dorsolateral Prefrontal Cortex and why it’s not the lone seat of intellect
For whatever reason, from the pop science folk all the way to avant-garde Harvard graduate leaders of neuroscience and psychology research, it is seemingly universally accepted that the sole purpose of the brain is to emerge intelligence, that we are cognitively miles ahead of animals, and that a sense of reasoning is either somehow manifested globally across the brain or exclusively in the frontal cortex. I do not desire to go against psychometric g, perhaps nearly the only thing we can objectively rely on in a psychologist’s analysis. Neither, for a naive observer, whose judgement resembles Plato’s arrogance of having the status of homo sapiens sapiens, is it an entirely nonsensical thought to recognize the correlation between the expansion of the frontal lobe and our development as a rational species. But in my own stroke of ego, let me play Diogenes and strip the chicken of its feathers. As is, often without understanding of what it actually means, perpetually reiterated to any hopeful researcher by the laymen:
“Correlation does not imply causation”.
This saying, like the one of ad hominem, has become a misnomer used by any subject uncomfortable of being taken down a peg, especially if they are coming from a place of vague implications and moral, yet ungrounded, justifications for equality of outcome, rather than opportunity. However, when I say it, I do not intend to discredit legible research with some vague sophistry, I intend to use it as it was devised. And that is to say that neither factor precedes the other, but that instead, both of them are a key symbiotic duo, perhaps with other characteristics, that has enabled us to transcend being a mere animal, which is the phenomenon through which they correlate. The capacity to grasp novel situations and concepts is not a sufficient prerequisite for becoming what humans are. It is my conviction that deliberated behaviors, habits and social functioning are parts of the brain supported by, but ultimately independent of, reason. And it is this belief, and the association of those two with the aforementioned frontal lobe and its development, that I’ll be making a case for in this article.
But first, some elementary neuroscience. There are many parts of the brain, but conventionally, it has four lobes: parietal, frontal, occipital, and temporal. The most posterior, that is to say the closest to the back of your skull, is the occipital lobe concerned with using the primary human sense of vision, another trait exclusive to us which in nature is only superseded by birds of prey which have developed it to this degree only to recognize prey from very high up in the sky and they do not use a wide visual field to interact with the world. It is the only lobe exclusively concerned with making sense from a single human sense and you will not find it has much use besides this function, especially the most posterior parts of it. Anterior, that is to say closer to your forehead, there is a split in the form of a sulcus between two lobes, the temporal and the parietal, each of them being direct neighbors of the occipital lobe. The temporal lobe is primarily concerned with a combination of memory and the sense of hearing, alongside feature binding and a little bit of emotion and overlap with the limbic system.
The parietal lobe is slightly concerned with a sense of touch, but far more importantly, with a sense of space, geometry, mathematics and a key quality I will discuss later. And finally right behind your forehead you have your frontal lobe, which is concerned with, as is the key part of this argument, the motoric/muscular output in all degrees of habits and decision making diagrams on all levels as a clockwork being, at the inclusion of the clockwork maker which can encode and even spur these motoric sequences up in a matter of seconds if it is necessary to do so.
All of these lobes interact without cessation so as to make a rational human being capable of fulfilling the Darwinian evolutionary purpose of thriving and surviving, especially in our highly specialized, large scale cooperative, predictable industrialized age. For the most part, the endless stream of the occipital lobe combined with the context of the temporal lobe integrate into the spatial and coherent representation of the world by the parietal lobe, to which the frontal lobe reacts and makes motoric structures for. It is important to note, that from the perspective of platonic realism, we are merely distant in a certain direction of what makes sense in the universe from point naught, and there is nothing but our coordinates making it so. There can be a very distant alternative universe developed in a completely different direction, where for example left and right do not exist or where all being is merely two dimensional, as is explored in the novel called Flatland. It’s our omission of the trivial in our day to day consciousness and lack of imaginative capacity that makes us ignorant to this fact. With that in mind, let us delve further into the research implying the frontal lobe as the seat of intellect, namely the Dorsolateral Prefrontal Cortex(DLPFC).
Whenever an individual speaks of abstractions, keeping a large amount of entities within the preoccupation of their mind, or having acquired a skill or capacity, it is not rare for it to be associated with intelligence, but it would be flawed to associate it with reason in a pure sense. All of these functions are either the result or the engagement of the DLPFC. They describe a system of diagram design and codification, which is precisely the role of the DLPFC. It’s the programmer that makes you able to learn skills, have executive functioning, control impulsivity, keep up appearances, mitigate disasters and also do abstractions. When I keep arguing for the frontal lobe not being the seat of intellect, why then do I assort it the role of abstractions? Because while you may perhaps call me a fool, I do not think the use and combination of abstractions, especially if practiced, necessitates reason. Since ultimately, at the end of the day, abstractions are models of reality which are merely high-level decision making diagrams, which is why it is no wonder they are localized at the clockwork of motoric sequences. If a precise execution of a singular muscle at a specific tone is the lowest-level cog or motoric representation, then abstractions would be rather high up, perhaps only surpassed by things like religion or utmost conviction of belief. And yet that is still not what reason is.
Why? Why is that not reason? And what is reason? Because, as I mentioned prior, this is merely a clockwork with a clockwork maker. If you strand an ordinary clockwork maker on an island north enough on the globe to lose the orientation of the sun, and leave him all the tools, but merely those, to make an improvised clock, then no matter how diligent or sophisticated his clock is, it will not have its key ability of telling what day it is. Ultimately, the error margins of no reference point will compound into greater and greater errors and the whole matter becomes a useless frustration, because reason transcends constructionist tendencies. It would be hypocritical and vain for me to deconstruct a placeholder and leave a vacuum, and so I will answer the last question of what reason is. The origin of psychometric g is in the realization that all domains that necessitate some competence of the mind have a universal underlying latent variable.
This variable is most efficiently tested, however, with a test called Raven’s Progressive Matrices. It is a test for which you cannot prepare, and which marks something biological, although not necessarily entirely genetic. Therefore, whatever this latent variable is and represents, the Raven’s Progressive Matrices test will be the most helpful at illuminating it. An analysis of this test reveals it has two sorts of problems: multiple simple features repeated across the matrix, and a not so easily discernible gestalt, which cannot budge to being divided into multiple simpler parts. The first part is lucidly the DLPFC, as is derived by its clockwork maker and maintainer of abstractions and reactions to stimulus. However, the latter part is seemingly independent of it. And this part is not related to the frontal lobe, it’s related to the posterior parietal lobe, which is concerned with those gestalt perceptions. This is where we come full circle to the clockmaker and the seemingly tangential Flatland.
A clockmaker needs a coordinator, which can aid not in the devising of the diagrams of behavior, but in the decision making that precedes the devising of those behavioral diagrams. The coordinator precedes the models of the world in a holistic gestalt manner of comprehension and allows to be interpreted for motoric structures and the whole clockwork of abstractions. I do not think it’s a coincidence spatial and touch-related words are used to describe reason and comprehension such as understanding and grasping. It most likely arises from the cross-firing of proximal brain areas which cause this connection in qualia. Besides it, in empirical proof, a stroke to the parietal lobe causes far more damage than a stroke to the frontal lobe for scores of reasoning ability, in spite of the latter compromising judgment, social integration and one’s role in society, which is quite congruent with my proposed function of the lobe.
A point related to this that I want to grapple with is the left brain and right brain division of functions, which is described as global and localized. Albeit this observation has a grounding of science, namely that of hemispheric strokes, the elaborated theory on it will not be entirely precise. At the risk of misunderstanding and simplifying Dr. Iain McGilchrist and other makers of interesting left and right brain hypotheses, I will have to propose that at least a great portion of them actually describe the dichotomy of the posterior parietal lobe and the frontal lobe. Therein additionally lies a potential clue as to what the posterior parietal lobe is, if anyone will desire to explore it from a symbolic and cultural perspective. A few other bold guesses of mine would be, that it describes the dictating core of reason and in some cases one’s experience of god’s advice and that in terms of qualia, it is nearly always manifested as external to the point of nearly another sense added to that of vision and hearing and all the others and barely ever recognized as of one’s own creation.
