Thursday, 14 August 2014

Critical Thinking: an Art we traded for Agriculture.

In years before agriculture, man lived in smaller groups where skills were most likely not divided amongst its members. This would mean that an individual would have to have a complete skill set to survive, and be able to process and overcome the never-ending variables that nature threw at them: this was critical thinking. Humans then had a simple choice: use it or die.

Neuroscience has recently shown us that the brain is pre-wired (but developing through adolescence) so that any cortex neurone has the potential to connect to any other, directly or indirectly, at any distance, in the brain. We would not have this nerve structure if evolution hadn't promoted it as a 'successful' model.

Below I will try to explain how we used to use our brain, and compare that with how we use it today.

This essay contains some references to neuroscience: Please click here to show/hide a short description about how neurones and neurone networks work.

A basic neurone basically resembles a cell with coral-like 'arms': its multiple 'receiver' arms, dendrites, project at all angles from most of its circumference, and a single slender 'sender' arm, the axon, usually much longer than dendrites, can extend to connect to another neurone's dendrites through axon terminal branches of its own. Most axons are very short, but even if one extends past another neurone it would like to connect to, it can sprout a terminal 'branch' anywhere along its length.

Basic structure of the human neurone

Most of our cortex neurones reside in an outer layer that we call grey matter, and they are immobile once 'placed' during brain development. Below this (in a layer towards the interior of the brain) is a layer devoted to carrying the longer axon arms carrying signals between neurones in different parts of the brain: these axons have a myelin sheath that is thin and almost transparent if the neurone is unused, but this grows thick to better protect and strengthen a neurone's signal when it is used often; the myelin's whitish colour gives this area of the brain its name, white matter.

fMRI scan of White Matter (axon connections) between distant neurones in the human brain

Only very recently was it discovered that these axon arms connecting different regions of the brain extend, in a pattern much resembling a map of Manhattan, to all extremities of the brain, allowing almost any cortex neurone the possibility of connecting to another even distant one (and other deeper centres of the brain).

Close Section


The brain is 'wired' for critical thought from birth. Thanks to recent (f)MRI and PET brain-scan technologies, we can see how different regions of the brain are linked together, meaning that any neurone in our cerebral cortex has the potential to connect, either directly or indirectly (through other neurones), to any other.

The question we have to ask ourselves is: Why are our brains that way? If we had never had use for the extensive neurone-connecting abilities of the human brain, why did evolution promote that model as 'successful'?

If we look back at our evolution, we'd see that we spent most of it, hundreds of thousands of years at least, as hunter-gatherers. Hunter-gatherers lived in small groups, moved with animal migration, and lived in caves and temporary shelters; they were practically one with nature. I would imagine that each individual would have to have a complete survival skill set, as tasks don't seem to have been divided between community members as trades in those days - perhaps between the sexes, but there is little proof supporting that idea, either.

Anyhow, these skills had to be taught to younger humans: Hunting and gathering for everyday survival, as well as the dangers that represented wild animals; I'm sure these lessons were quite strict, as any deviation from them would be a threat to tribe survival. Medicinal knowledge and theories about the origins of the elements and other natural phenomena were probably practiced and passed along by a select few tribe members. In all, the 'unexplainable' aside, the methods they passed through the generations were tried and true, almost a science in those times.

A human that must fend for itself against nature to provide sustenance for itself (and eventually its family) would at least have to be close to maturity in body, so we can assume that the time until then was spent on education. Yet this education would be worthless if the young human didn't break the bond with the rest of the tribe and forage out for himself for a first time; when in his group of 'trusted teacher' tribe members (and he probably, by instinct, feared anyone else), he depended on them for approval or disproval of his imitations of their methods, but eventually he would have to test them against nature with only his survival as a judge. The 'walkabout' is an example of this still existing in Australian aborigine tradition: take what you've learned (from your elders and ancestors), use it fend for yourself, or die. The switch to critical (independent) thinking was not a choice then, it was a matter of survival.

Yet before that initiation, if an information has only been tested through imitation against a trusted member's expression of approval or disproval, the human brain can only categorise it (with other similar information) with a link to the emotion generated when judgement was given (by trusted member, and most likely linked to (emotional) information connected to trusted tribe member themself); this is completely at odds with the context of a real-life situation.

Here's an exercise for the sake of example: consider a task that you repeat so often that it has even become mundane. Can you remember who taught it to you? Now consider another subject that you learned but have had little-to-no experience actually using. I'm sure you still remember its teacher quite well.

When a young human sees an animal in a 'real-life' hunting situation for the first time, it becomes an actual goal (and means for survival), everything about his lessons changes. Place yourself in the same situation as the young hunter: you're about to embark on your first one-on-one with an animal, and your lessons have to relate to ~it~ (not dear teacher), so thoughts about your education process are not the first thing on your mind. What you are experiencing now is ~yours~ (and you may at first feel afraid at this, which will only heighten your senses and accelerate your processing): see how the animal parts the bushes as he runs into the forest; your brain will make a direct link from that observation to the size and direction of that animal (amongst other conditions), and when you enter the forest in the right direction to actually see the animal again, that earlier connection will be labelled 'success' and the 'teacher approval' filter will be needed no more. Did you lose the animal again when you entered a clearing? Notice that smell, note the wind direction, and follow it, and again, if successful, your connection will be rewarded and 'confirmed'.

That night when you dream, you will re-enact those events, making the new connections that 'worked' even stronger (added axon terminal arms, dendrite arms, and myelination), and should you encounter the same situation the next day (using those neurones again), the connection will become stronger still. Any slight variation to those circumstances will add additional information to the established links, making a 'hunting' neurone network that is your very own creation, your tested experience alone. One can imagine that with a lifetime of experiences such as these (in all methods of survival), the complexity of our neural networks must have grown great indeed.


Enter agriculture. This invention, only 12,000 years ago, flew in the face of over ~200,000 years of evolution and tradition. No longer was a human at odds with nature, as it needed stray no further than the boundaries of its habitat to collect its needed nourishment; many 'old' lessons about nature and survival were no longer needed, no longer given, and no longer tested.  Community size grew, and the work required by agriculture was divided between its members; it was no longer required to have a full survival skill-set to earn one's sustenance. Repeated tool-use skills in a sedentary environment requires much less critical thinking than the ever-changing circumstances of nature.

So, even though agriculture reduced the skill requirements for survival, the human brain was still 'wired' to handle them. And even though the human brain was wired to make direct inter-neurone 'conclusion' connections of its own (as a requirement for survival), it no longer encountered the circumstances nor the motivation to do so.

Yet because of our evolution and instincts, even in village (agricultural community) life, central leader role models remained, and were promoted to important places in society. Fewer were trained to brave the dangers of 'outside the village' (and these often became leaders), and even fewer had the occasion to test those skills. So from then, rumoured dangers, because untested, remained in the 'feared unknown' category, and directly linked in the brain to the 'authoritative' person who spoke of them. I imagine that over the years those stories, because they were untested/untestable, grew increasingly fanciful, and that the person telling them became an increasingly central village figure. This is probably how religion began.

So let's fast-forward to today, a mere 12,000 years later. This time period is next to nothing in the scale of our evolution, so our modern brains are practically unchanged from the hunter-gatherer model evolution favoured, yet with our cities protecting us from both the elements and nature, we are even ~less~ required and motivated to make the transition to the independent critical thinking that 200,000 years of evolution prepared our brains for.

The timing of that transition can change, too. In pre-agriculture days we had no other choice but to remain in a protective environment with our untested learnings until we were physically strong enough to affront nature on our own, but today, thanks to information technology and the (non-dangerous) nature of the things we learn, we can test any idea or information anytime we want in our lives... if we want to.