Is Brodmann Area 10 the Key to Human Evolution?

[Note to readers: I have been working on some diagrams for this post but they are not coming along as desired. If I finish them any time soon, I will edit this post and add them in! Meanwhile, let your mind's eye do the imaging. George]

Judgment and the Prefrontal Cortex

A little over a decade ago I started to develop a theory about why human beings were coming rapidly to face multiple global disasters of their own making (global warming and climate change, peak oil, peak water. and general resource depletion). I had come to the conclusion that individual human beings could be quite clever, that is, they can possess both high intelligence and great creativity. They are able to apply this cleverness to all form of problem solving and invention. But I realized that what was only poorly developed in humans was the capacity to make good judgments with respect to what have been termed "wicked problems". These are the most complex problems (high dimensional), usually social in nature, arising from dealing with large complex systems in uncertain and ambiguous situations. Additionally, humans tend to approach even local problem solving with something of an engineering bent. Curiosity along with determination to conquer nature give rise to the engineering attitude that drives to discover solutions to problems even when better judgment would have said that, perhaps, that particular problem should best be left alone! For example, advertising is seen as a way to solve the problem of how to get people to buy more useless, even dangerous stuff.

Psychologists who had long been probing the nature of intelligence began to realize that there was more to intelligent decision making than could be accounted for in just looking at, say, memory speed and capacity, rule learning competence, and so on (what is known in intelligence research as "general intelligence — g". They began to look at a broader definition that included something that was seemingly more ephemeral or at least more fuzzy in that it wasn't something that test subjects were conscious of, as they were in the actual making of a decision. The psychologists began to construct a model of what might have been called 'extended intelligence' or 'subconscious intelligence' that began to look more like a related but separate cognitive facility we generally call judgment (see also: Sapience, Intelligence, and Creativity Delineated).

Judgment involves a subconscious cognitive process that brings tacit or implicit knowledge to bear on decision making taking place in conscious, deliberative intelligent processing. Antonio Damasio [1] first demonstrated the role of emotional or affective influence on so-called rational decision making. He showed that affect plays a crucial role in biasing the process of traversing a decision web where the various nodes (decision points) are tagged with valences (good/bad, positive/negative) based on past experiences and past outcomes of similar decision situations.

Our judgments are affective but they are also formed by more general implicit models that we learn over the course of a lifetime. Experts do this. They learn to make rapid, correct judgments on a variety of situations in their realm of expertise. They do not use excessive amounts of time going through a deliberative process testing learned explicit rules one after the other. Their expert judgments are produced as intuitions from their vast storehouse of learned implicit knowledge processed in parallel.

There are two evolutionarily significant developments of the human brain that seem to be directly involved in this capacity to bring vast amounts of experience (models) to bear on decision processing. The first is the late (maybe 200k years ago) expansion of the frontopolar patch of prefrontal cortex designated as Brodmann area 10 which appears to have more than doubled its relative size in Homo sapiens compared to earlier hominin species (that is relative to other prefrontal cortical patches). The other is the many-fold increase in the number of Von Economo (VE, or spindle) cells in humans relative to other hominoids. These cells, with their cell bodies situated in anterior cingulate cortex (paleocortex right behind the prefrontal cortex) and the frontoinsular cortex (which includes Brodmann area 10 in humans!). VE cells have dendritic (receiving) projections in many of the nuclei of the primitive (so-called reptilian brain) striatum and the amygdala (which mediates fear responses). The VE cells have very large axons and dendritic processes which are highly myelinated (for insulation) making them extremely rapid conduits for signals between these areas. The direct connections between limbic nuclei and paleocortex and prefrontal neocortex is highly significant. The prefrontal areas, especially Brodmann area 10, are implicated in a growing body of neurological evidence with planning, foresight, and judgment. These are components of what I have termed sapience.

Evolutionarily the very sudden relative enlargement of Brodmann area 10 and the explosive increase in Von Economo cells (along with the increased reciprocal communications channels between BA10 and all other parts of the prefrontal cortex (PFC) as well as with limbic centers) signals a qualitative change in hominin cognition. In fact this is, I claim, the beginning of true sapience in our species. Sapience includes the capacity to make good moral judgments. Woodward and Allman [2] have written an extended essay laying out the evidence for the role of Von Economo cells and various PFC regions in producing the phenomenon we know as intuition, which they claim is a form of subconscious decision biasing based on tacit or implicit knowledge. It is a more elaborate form of affective biasing as developed by Damasio (above). They make the case that moral sentiments and moral guidance of decisions we make is essentially similar to affective intuitions. That is, our moral intuitions arise from the limbic centers and are evaluated in the PFC for incorporation into our decision processes. Moral intuitions are generally subconscious in origin in spite of claims made by some philosophers that we humans engage in moral reasoning. The latter would depend on their being a set of moral facts or veridical claims about right and wrong actions with which our reasoning (intelligence) system would work to produce a conscious moral decision. But the psychological evidence supports the view that our moral leanings are based on intuitions and 'gut reactions' with only a small, a posteriori input from reasoning. If most of us think at all about our moral persuasions it is after the choices are made and actions taken. That thinking (a posteriori) is what helps evaluate the outcomes (good or bad in the emotional sense) and learn from our successes and mistakes. What we learn is more tacit knowledge or more refined subconscious models of how the world works. This new or refined knowledge is what will be brought to bear in future similar scenario situations.

Wisdom, Judgment, and Intuitional Thinking

Wisdom is the most advanced form of intuitional thinking, with a healthy dose of good moral judgment for both decision guidance and later evaluation of success or failure. All of our tacit knowledge of the world, other people, ourselves, and so on, is made available to the planning regions of the PFC (BA10, especially) via rich connections to the association cortices (posterior frontal (action selection), anterior parietal and temporal lobes primarily) and to the limbic (emotional and drive centers) via VE cells. Moreover, the sapience power helps to guide the learning process itself. It guides us in deciding what aspects of our environment and our inner selves we pay attention to when things are changing and learning new relations may be required. In other words, wisdom guides our becoming wiser as time goes on.

The basis of intuitional thinking and sapience is more ancient than modern man. Judgment processing has been around ever since the reptiles ruled the earth and possibly before that. The thalamus (primitive perception) and basal ganglia (primitive behavior control) are very ancient parts of the brain. Before more elaborate cortical structures emerged, these, along with a primitive 'sort-of' cortical structure, the amygdala, were responsible for producing adaptive behaviors that were instantiated as much by instinctive (hard wired) reactions to narrow aspects of the animal's environment. If it is small and moves, eat it. If it is large and moves run away! The paleocortex and later the neocortex emerged to produce more refined decision processing and, through more elaborate representation schemes (memories), more adaptable and elaborate behaviors. The advent of the neocortex and its subsequent expansion, in particular the evolutionary expansion of the prefrontal cortex, extended greatly the scope of what animals could do in terms of modeling the environment and laying more complex action plans (behaviors).

Elkhonon Goldberg has posited the role of the PFC is really just an elaborate and more complex reflection of the roles played by the basal ganglia in animals with more primitive brains. The difference, he suggests, is that the scope or context of decision processing handled by the PFC is much larger, broader, than that of the primitive centers. The same is true on the perceptual side by the role of the posterior portions of the parietal and temporal lobes (all other senses except smell/taste) and the occipital lobes (vision) and that of the thalamic/amygdala and a few other miscellaneous sensory-related centers [3] (cf. Chapter 12, section: The Cortex and the Striatum).

It is clear that the PFC is the ultimate command center in terms of organizing thinking behavior, calling up stored knowledge and models (which by the way should be considered as simulations of how parts of the world work carried on in subconscious memory) and directing the intelligent flow of processing that gives rise to decisions selected to accomplish a plan. The latter is organized in order to achieve a goal, any goal from simple conquest of an object of desire to satisfy a lust to a strategic plan to conquer an enemy. The PFC calls upon all other areas of the brain to accomplish this organization and temporal processing (thinking, whether conscious or not). There is growing evidence that it is the role of the BA10 patch to act as the final convergence zone for all of the results of all of this processing and to, in effect, summarize it all into an on-going narrative that it literally tells itself. This is what we experience as consciousness.

No one would likely argue (any more) that dogs or chimpanzees are not conscious just because they do not possess language in the form we would care to use that term. They do communicate with one another and often with humans. And at this stage of our knowledge of what their cognitions might be like, we generally grant them consciousness status, at least insofar as their awareness of the world outside of their own heads and especially the mental states of others of their own kind. But with us humans there seems to be a much more extensive and elaborate (greater scope) awareness of being aware, or what has been termed second-order consciousness. Is it possible that the sudden expansion of BA10 and the increase in VE cells in the H. sapiens brain provided an essentially new way to map a model of our existing models/maps of awareness?

This remains fairly speculative, but the tools and methods for exploring the question are either already here or are in rapid development (e.g. newer imaging technologies for finer resolution in time and space). What seems less in the realm of speculation is that H. sapiens developed much more complex and elaborate cultures subsequent to the expansion of BA10. In other words, humans demonstrated a tremendous enlargement of the context to which they attend and a greater capacity to explore new possibilities (technologies, invention, new territories, etc). With this expansion of context came a new demand for increased capacity to learn and use much broader tacit knowledge; to develop intuitions over much larger scopes of time, space, and conspecifics. And since this involves adaptive behavior, the complexities of how to model conspecific behaviors, how to anticipate their actions by anticipating their mental states, became extremely recurrent.

Do We Have Enough Sapience?

Wisdom represents the ultimate achievable subconscious understanding of the world and the self. It requires a strong competency of the PFC, but especially the BA10 area. The latter coordinates strategic thinking, interprets moral intuitions, and guides the attention to focus on the most important aspects of the environment, its dynamics, its evolution, and, perhaps most importantly, its future. My own observations and speculations about the state of wisdom competence in modern humans is that we are really not very wise as individuals, relative to the context of the environment that we have created with our technologies, institutions, and general cultures, all products of great cleverness to be sure. A central question is whether our current lack of wisdom competence is due to inherent weakness in the brain (BA10 and VE cells) or due to a paucity of stimuli in the environment during development — no real good examples of wisdom in action that could be used to boost competency while growing up. We know that a paucity of rich sensory stimuli can stunt the development of general intelligence. Might this also be the case for sapience?

There are a few reasons, based on biological principles, to suspect that this isn't the case when we consider what level of competence might be needed by the average person in order to correct our current situation and prevent any more mistakes of judgment from occurring in the future. One of these reasons is the fact that the level of sapience we have achieved (on average) was done so recently in evolutionary time. New traits and behaviors often start out as weak responses. There isn't enough evolutionary time for enough allelic variation to accrue to produce the characteristic bell curve associated with more developed/ancient traits (e.g. general intelligence as measured by standard IQ tests). Distributions of these traits tend to be much more skewed toward the low end. A majority of the population will possess a weak form of the allele responsible with very few 'sports' having stronger forms. I would guess this is the situation with respect to the genetic basis of sapience in humans.

This brings us to an interesting speculation. If our predicaments are fostered by being overly clever but not adequately wise (due to weaker sapience) it seems that at least one solution would be to alter either cleverness (lower it) or sapience (strengthen it). There are those who argue that we are already in the mode of unconsciously dumbing down our species (see the movie Idiocracy for an explanation! See also: Sympatric speciation). Given what we see going on in the political and economic realms this is actually quite a believable hypothesis! But there might also be a trend in assortative mating of more sapient people as well. Just perhaps, if we had enough time to let things sort out, we would witness the speciation of Homo stupidus along with that of Homo eusapiens. Of course the problem is that it is starting to look like we really don't have the time to wait. Also, there is the possibility that the former will breed in such numbers as to overwhelm the latter species.

A final speculation with respect to an alternative approach to the human predicament. We already know that the rapid expansion of BA10 and VE cells marked a turning point for human evolution. Such rapid changes in a biological feature requires some kind of modification (mutation) in the genetic expression control network of DNA (a lot of what we used to think was 'junk' DNA turns out to be part of an elaborate network of expression controls that determine morphology and behavior! See: Evo-Devo). It is altogether possible that a tiny bit of control DNA underwent a mutation that caused it to express a particular gene during BA10 development causing, say, the development to go on longer, leading to a larger patch. (or alternatively VE cell elaboration which might have secondarily affected the development of BA10). We do know that a significant part of brain area development is stimulated by actual excitation from other areas whose neurons start firing spontaneously in embryonic and fetal stages. Experiments that subdue this firing result in stunted development of the target zones for those signals. Thus there is an aspect of demand-driven development based on a few key zones. Suppose that BA10 underwent this expansion as I've just described, due to a point mutation. Since BA10 communicates reciprocally with all other areas of the PFC, and they, in turn with everything else, is it possible that the expansion triggered greater development in the other cortical areas as well, including the elaboration of VE cells?

Accelerated Sympatric Speciation

Such a possibility suggests additional possibilities. The control segment of DNA could have a slightly different level of impact on different alleles of the gene being expressed (in reality these expressions often work in a cascade effect, where turning on one gene turns on - or off - others). This would explain the distribution of sapience competence above. It would also suggest a strategy for improving sapience and hence wisdom. Find the markers for alleles of the gene that are most active under the influence of the control DNA and actively select for those. The latter does not necessarily imply eugenics or genetic engineering, though those are not precluded. All that would be necessary is to start a registry of potential eusapient allele possessors and provide an assortative mating dating service! Let nature do the rest. No coercion. No manipulations. Free choice among participants once they decided to participate. It is possible to devise psychological tests (some already exist) for detecting the potential for wisdom in younger people. Once the genetic marker was determined (assuming it exists) it would be trivial to test for the allele and award those who have it and are looking for mates with similar mentalities a place in the registry and service. I rather like this idea. It even gives me an idea for a business plan! Oh wait. A not-for-profit plan!

Though this might seem a far fetched idea I can only point out that when I started to become suspicious about BA10 and the role of wisdom in our cultures, there was not a whole lot of evidence that that little PFC patch held this pinnacle position in cognitive capabilities. I inferred it partly from what was missing in the list of executive functions being developed for other patches and brain regions and partly because of its evolutionary history and the correlation between that and our sudden development of language, culture, and, apparently, second-order consciousness. Now the results are coming in more rapidly than I can keep up with them. But so far the results have bolstered my claims, so my confidence in my further inferences grows as well.

One thing seems fairly certain to me. Our world, the world of Homo sapiens will be rapidly coming to a close as we struggle to adapt to the vagaries of significantly reduced energy flows and climate change effects. It is not at all certain that we, as a species, are prepared to adapt to these conditions. On the other hand, evolution works by having variants in a population that are able to adapt to changed conditions and be more successful breeders under the circumstances. People who are sapient enough to be wisely adaptive in some future radically different world already exist in our population, but they are likely rare. Many of them probably wonder what is wrong with them, why they think differently from everyone else they know. They have no models to compare to. It must be confusing for them, especially when they are young and just starting to notice the differences. If we could somehow find them and support them (e.g. the village of 500, the University of Noesis!) they might just provide a seed population for a humanity form in several thousand years.

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References

1. Damasio, Antonio (1994). Descartes' Error: Emotion, Reason, and the Human Brain, G.P. Putnum's Sons, New York.
2. Woodward J, Allman, JM (2007) Moral intuition: Its neural substrates and normative significance(pdf alert). J Physiol Paris 101(4-6):179-202.
3. Goldberg, Elkhonon, (2009). The New Executive Brain: Frontal Lobes in a Complex World, Oxford University Press, New York.

Comments

[Robin Datta]

Human cognition is a significant emergent epiphenomenon that rests on a hierarchy of multiple levels of epiphenomena for which we have constructed coherent presumptive explanations. Matters beyond our ken cannot and do not have to be so accommodated. We have no basis to posit or reject further levels beyond human cognition.

Perhaps however, understanding human cognition may require operating from such levels.

[bob]

just an idle thought; recently a connection was made between crisis environments and more-rapid mutations leading to helpful genetic solutions. is it possible a human bottleneck pressure event (such as the toba volcano approx 70k years ago) may have precipitated/supported the presence of a higher order of consciousness related to more cooperative reliance required? and, if so, then would the possibility exist that dynamic pressure would refocus improvements?
wanders off...

[Florifulgurator]

Interesting thing: Homo Floresiensis (not related to me) seems to have a BA10 similar to ours in relative size, yet the brain looks more like Homo Erectus. (Falk et al. 2005 http://www.scienceonline.org/cgi/content/abstract/1109727v1 )
So, perhaps BA10 is older than 200ky? Or not unique to Homo Sapiens?

Anyhow, I no longer disregard your theory/plan a science fiction... Looks you got a plan! But, do we have enough time (10y for the genetics + 20y for the first breeding results)? And would it make a difference (with 8 billion old brains around ca. 2040)?

[George Mobus]

Robin,

By "levels beyond human cognition" do you mean social organization, as in the latter emerging from the former?

Bob,

Excellent conjecture. If there is anything progressive about evolution it is that it tends toward greater information handling capacity (bigger brains), but that just leads to greater diversity of behaviors. And that, in turn generates more information (news of difference). Ergo, major information generation sources, e.g. major climate changes, open up the opportunity for better information processors to evolve.

Flor,

BA10 is not unique to H. spaiens. Sorry if I left that impression. Rather it can be traced quite far back in the phylogeny of hominidae and perhaps further. I believe there is an equivalent (cytoarchitectonically) in rodents and dogs.

But it took a major leap in relative size with H. sapiens sometime within the last 200k years and might have just preceded the advent of complex language (some speculations on language in erectus, but nothing that seems conclusive).

George

[Robin Datta]

The "further levels beyond human cognition" refers to the possibility of dimensions beyond those which we cognize; if there are such dimensions, we exist in them even if we do not cogsize them.

[gerovital]

hello Robin
good to know about human cognition
ty