Fear of the unknown may be the result of cognitive bias.  If there was a group of Homo habili that looked down from their home base and saw that a group Homo rudolfensi had set up camp along their river, what would the Homo habilis do? Should they walk down the ridge unarmed and introduce themselves, should they just ignore the Homo rudolfensi and go about their daily business hunting and gathering fruits and nuts in the valley? Should they scout the group and then decide to surprise attack? Should Homo habilis send a group of armed individuals down and introduce themselves to the rudolfensi? What would the rudolfensi do? The answers to these questions are not known, but for survival of the Homo habilis, walking up unarmed or ignoring the other group altogether could result in their annihilation, rudolfensi might attack them. So a fear of the unknown could be a tribal instinct that is itself a cognitive bias that has been genetically selected and helped the survival of our species and the extinction of others. And in this scenario, Homo habilis may have started projecting their cognitive biases forward (confirmation bias) in making a decision as to what to do upon encountering that unknown Homo rudolfensi tribe. Did they scout the village from afar and see evidence of their cognitive bias, their fear of the unknown?  If so, could this be confirmation bias? Did they then plan and attack the village? If so, this would explain how Homo habilis survived (and rudolfensi did not) and then evolved into Homo erectus and then us, Homo sapiens. This successful human evolution is the biological and biochemical basis for xenophobia today.


Discrimination based on race, ethnicity, gender, age or sexual orientation could also be a product of cognitive bias – as was the case described above with Homo habilis and Homo rudolfensi regarding race.  Someone today may have a preconceived notion, a prejudice, a cognitive bias, about any such group other than their own and apply that prejudice to that individual or group. This kind of discrimination could be the result of the cognitive biases that have been genetically selected and neurologically wired over the course of the successful evolution of Homo sapiens, including the next step of looking forward and applying a confirmation bias, which habilis probably did with rudolfensi, and which is now present in us, the sole dominant Homo sapien species of today.  Our brain’s perception of the world, our neuroreality, is influenced by our evolutionarily selected and genetically expressed cognitive biases from our evolutionary past.


Smithsonian National Museum of Natural History


What was the underlying cause that resulted in Homo sapiens becoming the sole and dominant human species on the earth?  One answer could be that cognitive bias, confirmation bias and argumentative theory were survival mechanisms that were genetically selected for that now appear in Homo sapiens.  How could these traits be the most useful in the survival and dominance of a species over the last 4 million years?

In an extraordinarily complex world with and infinite number of stimuli and social circumstances that can surround an individual, perhaps it was beneficial to have a cognitive bias. Rather than analyze an infinite number of stimuli and social circumstances, the brain takes a short cut and has cognitive biases that allow the individual to make quick decisions and survive in his environment. 

Let’s review Argumentative Theory: Argumentative Theory is a concept proposed by Mercier and Sperber in, Why do humans reason? Arguments for an argumentative theory: "Reasoning is generally seen as a means to improve knowledge and make better decisions. However, much evidence shows that reasoning often leads to distortions and poor decisions. This suggests that the function of reasoning should be rethought. Argumentative theory claims that the function of reasoning is argumentative. It is to devise and evaluate arguments intended to persuade. Skilled arguers are not after the truth but after arguments supporting their views. This explains the notorious confirmation bias. Reasoning so motivated can distort evaluations and attitudes and allow erroneous beliefs to persist. Proactively used reasoning also favors decisions that are easy to justify but not necessarily better. In all these instances traditionally described as failures or flaws, reasoning does exactly what can be expected of an argumentative device: Look for arguments that support a given conclusion."


From: A Conversation with Hugo Mercer
"Reasoning was not designed to pursue the truth. Reasoning was designed by evolution to help us win arguments. That's why they call it The Argumentative Theory of Reasoning. So, as Mercier and Sperber put it, 'The evidence reviewed here shows not only that reasoning falls quite short of reliably delivering rational beliefs and rational decisions. It may even be, in a variety of cases, detrimental to rationality. Reasoning can lead to poor outcomes, not because humans are bad at it, but because they systematically strive for arguments that justify their beliefs or their actions. This explains the confirmation bias.'" So here then, argumentative theory is an extension of confirmation bias.

So the Argumentative Theory as stated above explains the genetically selected human confirmation bias. So a more expanded explanation of human brain development may be that the genetically selected and neurologically wired cognitive biases resulted in the development of confirmation biases that explain the thought processes described in the Argumentative Theory. I make this statement from the evolutionary perspective. Have you ever been walking through the woods when suddenly nearby a squirrel runs up a tree, or a bird suddenly flies away – you jump, that’s the instinctive fight or flight response. That is exactly what the Australopithecus did when she ran away for protection from the rumbling in the bushes and when I ran to my mother after having seen a black bald guy for the first time.  This is a bias genetically existent in most animals and us as well, so this could very well be a cognitive hard-wired bias. So once such cognitive biases were in place in the animal brain, they could be applied down the evolutionary line in more complex situations. Upon encountering the rudolfensi village with their fear of the unknown cognitive bias, Homo habilis may have relied on confirmation bias, seeing evidence of their fear of the unknown, which may very well have been involved in their decision as to what to do.

This confirmation bias in Homo habilis could have then lead to the Argumentative Theory, an extension of confirmation bias as described above, which may have developed as Homo erectus migrated out of Africa 2 million years ago and inhabitted most of Eurasia in more complex tribes and villages.  This then lead to Homo sapiens, their exit from Africa 70,000 years ago, and their migration and dominance over the entire world.  This then lead to the development of agriculture and the advent of civilization some 5000 years ago, then the industrial revolution, and now the digital revolution and information age. In the extraordinarily complex society of today, the instinctive cognitive biases, the resulting confirmation bias, applied in the argumentative theory, may all very well be present in the 100 billion neurons in your brain helping to generate your perception of reality, your neuroreality.


Roscoe Orman, playing Gordon Robinson on Sesame Street

Homo habilis

Homo rudolfensi

A cognitive bias might also explain an inherent fear of the unknown. If a lone Australopithecus, let's say Lucy, was out gathering friut and nuts, and she heard some rumblings in the brush, what do you think she would do?  She would probably run back and seek protection in her larger group of australopithecus. If the sound was made by a predator like a lion, that cognitive bias resulted in Lucy not being killed by a predator. If the sound was made by a non-predator like an antelope, she didn’t have to leave for protection. But when in such a situation, if many individuals did not seek protection in a large group, chances are good a number of them would be killed by a predator, which would then lessen the chances of that species surviving. So evolution for the species genetically selected the cognitive bias short cut – the fight or flight response, in this case flight.

Here's a model of an Australopithecus, based on the skeletal remains found by Donald Johanson and Tom Gray on November 24, 1974, at the site of Hadar in Ethiopia. They nicknamed her Lucy

As a very small piece of anecdotal evidence, I recall an incident watching Sesame Street at the age of 3, I’m a white male. A black bald man appeared on Sesame Street reciting the alphabet, that was the first time I had ever seen such. I ran screaming and scared crying to my mother yelling “What’s that mommy, what’s that?”  She calmly explained that that was another person who happened to have no hair and different color skin, and that there are all kinds of people in the world of different color, shapes and sizes, that we were all the same people, and he was just like me.  After that I developed a liking for the guy and looked forward to seeing him again on Sesame Street.  But what was it that caused my initial response?  At the age of 3 there is no way I could have developed and learned a bias to a black bald man that I had never seen before, so that bias must have been that genetically selected and biochemically hardwired cognitive bias of fear of the unknown, which expressed itself here by extension as xenophobia.

Once the developing human brain had these cognitive biases as a means of survival, the next step would be to apply this bias in a forward manner in social context.  When your cognitive biases are in place, in new situations you look for confirmations of these biases, as most likely was the case with Homo habilis encountering Homo rudolfensi as earlier described.

Hugo Mercier

Dan Sperber

Chapter 7

Your Neuroreality

Remember the 100 billion neurons in your brain that create your perception of reality, your neuroreality. Let’s consider human evolution, brain function, cognitive bias, confirmation bias and argumentative theory as they may relate to neuroreality. As earlier mentioned, we evolved over the past 4 million years from Australopithecus, to Homo habilis, to Homo erectus, to Homo sapiens. Note that during these 4 million years there were other closely related human species, Homo rudolfensi, heidelbergensis, neanderthals, and the most recent of which were the florensiensis that went extinct only about 17,000 years ago.

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