The Neuroscience of Sinful Behavior

Morgan Levy, MD
Levystien Productions
Parker, Colorado
Copyright 2014
4,600 words



Most sinful behavior is actually instinctual behavior that comes pre-programmed in the brains of homo sapiens.  This behavior evolved during our hunter-gather past and is primarily designed to be used against out-groups.  We also have instinctual altruistic behavior that evolved to be used towards in-groups.  Modern agrarian societies created a new environment that has caused the definition of "in" and "out" groups to get confusing.  Before we became farmers we evolved to operate in mobile groups of 20-150 but we now live in sedentary groups of 500,000 or more.  Rules (sins) needed to be created so large societies could function and live together in peace.  Homo sapiens' are able to think outside their innate programming which enables them to be adaptable.  We can consciously change our behavior to adapt to a new environment.  Creating the list of rules we call sinful behavior allowed us to adapt more quickly and efficiently to this new environment.


Definition of sin?

"Sin is the act of violating God's will."   -Wikipedia 
"... for sin is the transgression of the law."   -1 John 3:3-5
"Wrong doing, particularly the breaking of moral or religious rules."  -Merriam-Webster dictionary
"Sin is the violation of a rule that instructs individuals to curb their instincts for the purpose of living peaceably in a large society."   -Levystien 2014


All animals are genetically programmed to do specific instinctual behaviors
Homo sapiens are the only species that created a list of instinctual behaviors that they are not supposed to do.  
Why did we do that?  ... and, what about the behavior of making up the list?  Is that behavior instinctual or did we somehow break free of our programming in order to do it?  Are we really able to think outside our innate programming? 
Why would the brain of a homo sapiens come pre-programmed to do the behavior of making rules that dictate we should not do other sets of behaviors that are also genetically pre-programmed?  How is it possible that a species could evolve to think outside its programming?
Let me re-state the question with an example.  If greed is an innately programmed piece of software that is in the brains of all humans, then why is there a second innately programmed piece of software in the brains of all humans that is capable of figuring out that the greed program needs to be modified?
Probably because we also have innate programs that do altruism and these programs are essential for our unusually intense degree of social behavior.
I thought you had to be taught by religion to do good stuff. 
In reality, we come innately programmed to do all sorts of good stuff.  Modern religions tend to plagiarize this programming.  We are innately programmed to do both good and bad things and some of us can think outside our programming enough to do the opposite in both a good and bad way.  Wow!
Think about that for a moment.


Did the creation of sin serve an evolutionary purpose?
I am going to do another thing that our brains are uniquely programmed to do ... storytelling.  Homo sapiens' brains are programmed to tell stories in order to most efficiently transfer ideas between brains. 
Once upon a time ... there lived a family called hominids, or great apes, of the class mammals and order primates.  They lived comfortably in the tropical rain forests where they ate plants and were safe from the cycles of ice ages that were repeatedly effecting the rest of the planet.  As they evolved and rose up the food chain their competition for resources became mostly other large animals.  To survive they formed groups and evolved social behavior.  Communication was limited and their political structure was that of a dominant alpha male who had absolute power and ruled over an hierarchical pecking order. 
Stick with me, I'm just providing a tiny bit of background.  I'll get to the sin stuff momentarily.
Around six million years ago an ice age receded opening up large expanses of savannah.  Soon there were herd animals running around and eating grass.  Some of the apes ventured out and evolved the ability to eat herd animals.  This turned out to be a bad idea as the ice was sure to return.  (... and high cholesterol was in our future! lol)  Over the past six million years the apes that stayed in the rain forests (ie. chimps, bonobos, gorillas, and orangutans) have undergone relatively little evolutionary change.  The apes who ventured out in the open faced repeated and harsh climatic change.  When selective pressure becomes intense it results in significantly increased evolutionary change.  Ultimately, the only ape that survived out on the savannah was homo sapiens
How did we make it?
That is a question that has driven the study of human anthropology since its inception and there is still more that is not understood than there is that is understood. 
Most evidence is of a circumstantial nature.  We can look at modern chimps and look at modern humans and figure out what is different.  We can also look at a few bones from hominid species that did not survive and observe what is different.  We can then say something like, "The brain of a modern human has an enlarged pre-frontal cortex and angular gyrus.  (The angular gyrus integrates sensory perception and the pre-frontal cortex does things like empathy, rational thinking and complex language.)  We suppose, "Perhaps these recently evolved brain structures give us new found skills that correlate with our survival?" 
It turns out that physically enlarged brain structures relative to body size are present in humans but, more importantly, there is significantly increased density and connections of neurons in these areas.

brain                       brain

The trait that is germane to this discussion is our newly evolved ability to think outside our programming.  (An ability that we do have by the way ... well ... at least some of us have.)  This trait is primarily facilitated by the dorso-lateral pre-frontal cortex.  In other words, the dorso-lateral pre-frontal cortex is the part of the brain that had the largest hand in creating sin. 
All modern religions that were created by large agrarian societies have a set of rules that contradict what humans are programmed to do.  Some would argue that we should be smart enough to not do these behaviors on our own and that we don't need a pope in Rome to tell us what not to do.  It is not that we are smart enough but that we are already programmed that way.  Instead of looking at innate human behavior and thinking, "That's not OK," I think it is more productive to try and understand why and how we developed programs that direct us to do the behavior that we see today. 
In that vein, one must ask the question, "Did the idea of sinful behaviors serve any evolutionary purpose?" 
The answer is yes, of course they did.  I'll explain.
Before I explain let's do a little story within a story.  There is this guy named Phil who is a big burly duck hunter.  He is a "good Christian" man and has a strong and unwavering belief system.  He loves and cares for his family and for his group of fellow duck compatriots.  He thinks homosexuals are sinning because they are having sex in a way that God said is wrong.  He does not believe that he is sinning by denying homosexuals their rights or by repeatedly demeaning them in public.
Phil made national headlines and got fired from his popular reality television show.  He was ridiculed on lots of talk shows and there was an especially funny piece by STEPHEN COLBERT.  The Tea Party began to champion him as a hero because he stood his ground for what he believes.  He stood his ground for what they also believe.  After several months A&E hired him back.  He still thinks homosexuals are sinners.


Is anyone confused?

After I explain why this kind of conflict exists in our modern civilized society you can re-consider Phil's situation.
As hunting/gathering societies gave way to agrarian cultures a number of problems developed.  These difficulties arose over a brief time period by evolutionary standards.  To brief for us to produce evolutionary change sufficient to fully cope with the new environment.  We were genetically programmed to run in small groups and to love and protect the in-group while distrusting and fighting out-groups.  That is only one of the problems that arose but I will focus on it for now to make this point.
Imagine that there were 1,000,000 humans in a single group but they were all genetically programmed to be in groups of 20-150.  These guys are nomadic, good fighters, and trained to protect their own. They are also trained to distrust and often kill those that are different.  They are now being asked to settle down and live in neighborhoods.  They must work and live together without doing bad things to each other.  Isn't this going to require a strong police presence?
How about if we make up a story line that enlarges the in-group by definition, centralizes authority in a father figure, prescribes ways to detect and avoid the bogey man, gives instructions about how to strengthen the in-group, and tells people how to eat, drink, procreate, sing, dance, meditate, etc?  How about if we get a marketing guru to come up with an ad campaign so we all buy this load of crap.  I bet if that crap load were to cost $19.95 a lot of us would buy it, right?
That is exactly what the early modern religions did.
Religious story lines may not be literally accurate but they are psychologically ingenious.  Policing with ideas instead of officers.  In order to get a million people to stop doing the seven deadly sins it would take a million officers to follow each individual around all day every day and who would police the million police officers? 
It would be far easier to market an idea about an invisible human-like being who has a single trait that is non-human and tell everyone that this makes him/her supernatural and that this deity we will judge us based on sin.  If a significant number of us buy into this idea then folks will walk around policing themselves. 
And guys like Phil will try to police you.
In addition, these early modern religions wrote their story line to take full advantage of how our brains were already programmed.  These religions figured out how to tell us to do what we were instinctually doing already. They just changed a few details like the definition of an in-group or the definition of the bogey man.  But we already had programs that were designed to think and behave in a certain way relative to an in-group or a bogey man. 
Thus, a great way to get an entire society of humans to basically follow a set of counter-innate rules is to make up a story about what happens to those who follow the rules and what happens to those who do not.  The really amazing thing is that even those that don't go to church honor the same moral and ethical rules.  These "sins" are created by religions but then become universal.  Guys who say, "The Jesus story makes no sense," would still agree that wrath, greed, sloth, pride, lust, envy, and gluttony are things we should not do even though they are things we are innately programmed to do. 
Well, some of us have brains that are just broken.  There will be more on that in a minute.


Charles Manson
Despite the ridiculousness of all religious story lines, religion itself is something we absolutely need.  Religion directs our innate programs to be used in a way that fosters the survival of an over-sized in-group.  Religion is an imaginary policing action that allows hunters and gatherers to live peaceably in large agrarian societies.
Our current problem is that we evolved too fast.  Our environment changed faster than evolution could change us.  Now we have programs that are in conflict with each other.  How are we supposed to know who to love and who to hate?  I know that I love the Cowboys and hate the Redskins but what if people are not wearing uniforms?
In regards to the "rules" or "sins" there are lots of ordinary rules and then there is a small set of the most fundamental rules.  We made up that these rules come from God or an ancient text or both.  The specific rules vary from religion to religion but the general rules, that the specific rules are a subset of, tend to be pretty similar.  For example, "Do no murder" is common to all these religions but the definition of which specific kinds of killing are OK, or not, may vary among different religious faiths. 


How does Levystien define sins?
I will use the seven deadly sins (wrath, greed, sloth, pride, lust, envy, and gluttony) to define sin for several reasons.  First of all, most of us agree that these are sins.  Second, they are sufficiently general to be universally applicable.  Third, most specific sins are covered under one or more of these broad categories.  Finally, I want to talk about how the human brain works and how it evolved to do certain types of behavior.  For this purpose I need a relatively universal definition of what the behavior is.


Who made up all these sins?
All sin was made up by human brains but most of us think that they were divinely inspired.  We easily believe that because one of our programs directs us to "have faith" that our "father" knows best.  Children need to come pre-programmed to trust daddy.  Those who are not programmed in this way find it hard to survive.  If you are going to market the idea of a God that judges our sin it would make sense to create a father figure.  We are programmed to understand that.  We are also programmed to have less trust for another human who is on our level.  For example, I would have more faith in what my dad told me than in what my same age friend said.  (Actually, when we become teenagers this one kind of switches in a very frustrating way for parents but that is another story.)  Therefore, if this marketing plan is to work we need to think that sins are rules that a father figure told us to follow.
If you agree with my assertion that all sin in all religions was created by the same genetically designed machine which is the human brain, then you should expect that all sins are likely to share a pattern or a design in common.  And they do.  As you examine different rules and move from specific to general you will find that the more you travel to the general side of the spectrum, the more that different faiths share the same beliefs with regards to sin.  The fundamental idea of sin is basically the same everywhere.


Where is all this going?
Why don't we go on a slight diversion into the future and see if we can predict whether all this thinking outside our programming will ultimately be a good or a bad thing.  How and why did our brains invent sin and will it save us or destroy us?
It might turn out that the ability to think outside our programming will ultimately cause the end of all species on this planet.  Or, we may avoid total destruction because we are so supremely smart that we figure out new science that prevents us from doing ourselves in.  Who knows? 
In any case, the question, "Did we need to do this?," is evolutionarily mute.  The only thing evolution cares about is survival.  The story of how our brains evolved in terms of exactly how and when we were being affected by this or that environmental pressure is not well understood.  I have to talk in "ifs" and "buts."  If we were like chimps six million years ago in the jungle, but then how did we change when we migrated to the savannah?  If we evolved an alpha male dominant hierarchical system in the jungle, but we don't think our frontal lobes were expanding back then.  If we were a tribe animal that lived in the forest and ate only nuts and fruits, but just how social were we?  If we became a meat eating social animal on the savannah, but which traits then imparted the greatest survivability? If, out on the savannah, we fought with other small groups for survival, but is that really why we changed to a more egalitarian system where everyone needed to help out for everyone's mutual benefit.  If this, then, but those that faired best were the ones that became the most intimately social, maybe.  If increasingly intimate social communication was the key, but is that really why we developed enlarged cerebral cortexes that allowed for integrated sensory input, complex language and empathic communication.  Or some such something or other...


For example:
Here is an example of human team work.  The Navy Seals.  These are guys who all get on the same page and all follow the same rules.  They all agree to think the same and believe the same things regardless of the accuracy of those beliefs.  This binds them together and gives them a competitive advantage. 


Here is an example of humans being independent individuals.  The Harvard debate team.  They are organized like a team but are inclined to have an endless debate with anyone including amongst themselves.


If a group of Seals and a group of Harvard professors were in combat who do you think would prevail?  A bunch of independent individualists who like to argue will have a hard time defeating a group of guys who value unitary beliefs and self sacrifice to promote the strength and survival of the group.
15,000 years ago nomadic humans settled down and became farmers.  Before they became farmers everyone probably knew what to do and how to live.  They were more like the Seals.  They did not sit around contemplating whether or not the definition of marriage includes same sex partners.  They had little time to consider things other than survival. 
Then, the civilizing process happened.  This process occurs in a species when food becomes plentiful and natural enemies become few.  Homo sapiens have become a civilized species.  Individuals can now worry less about survival and can sit around contemplating more leisurely pursuits.  Like the Harvard debate team discussing philosophy.  When you are programmed like Seals but become civilized and live in large societies you need a bunch of rules that tell everyone not to obey their innate impulses.  Sin had to be created in order to uniformly direct everyone to have the same manifestation of their innately programmed behaviors.   
If you live in a small group and you confront and kill a member of a competing small group, then nobody in your group is going to punish you.  If you live in a large society and confront and kill a member of another gang from another neighborhood because you define that individual as being a member of an out-group, then the head of the larger in-group that you both belong to will find you and punish you. 
Have you ever noticed that the definition of sin is rarely discussed? 
Doesn't it seem like everyone automatically knows what it is?  Phil knows what it is.  Could this be another example of our genetically programmed social bonds?  If the ability to understand that you must not sin is genetically programmed, how convenient is that for getting everyone to blindly follow the rules? 
Here is another example of programmed human behavior.  If you watch children on a playground you will see them doing behavior that is designed to teach everyone to fall in line and behave in a way that will make the group more cohesive.  We sometimes call this kind of behavior "bullying" because it seems out of place in the modern world but it is how we are programmed.
Things we are programmed to do don't need to be taught.  For example, we automatically learn language between the ages of 2-6.  It does not need to be taught at all.  Our brains come pre-programmed to learn the language of the in-group. 
Likewise, "bullying" is programmed.  All kids everywhere do it and no one is ever taught how to do it.  An innate understanding of what behaviors cause in-group cohesion to increase and what behaviors cause it to decrease is pre-programmed and does not need to be taught.  Unless the environment changes dramatically causing confusion and everyone needs to get back on the same page.  That is why we need to restrict our innately programmed desire to do bullying behavior.  It has become hurtful behavior to the larger in-group. 

Navy Seals who don't work in close connection with others or who want to argue all the time don't survive.  This is the kind of environment in which our brains were most recently programmed.  Kings and Popes hold on to the way our brains are genetically programmed in order to play us like we are marionettes. 

Here is a movie quote about confusing modern social rules with innate behavior.



Ricky Bobby- "With all due respect, Mr. Dennit, I had no idea that you'd gotten experimental surgery to have your balls removed." 

Mr. Dennit- "What, what did you just say, what was that?"

Ricky Bobby- "Well, I said, 'With all due respect." 

Mr. Dennit- "No, no, that doesn't mean you get to say whatever it is you want to say to me."

Ricky Bobby-  "It sure as heck does."

Mr. Dennit-  "No, no it doesn't..."

Ricky Bobby-  "It's in the Geneva convention, look it up!"

Here is the clip from Talladega Nights.


What about aberrant brains?
When a species is lost in time there is a lot of left over genetic garbage.  Some characteristics may have started to evolve in one direction, then the selective pressures changed and evolution went in another direction. 
What would happen to a species of birds if food became plentiful and predators went away?  Their wings would stop evolving and we would call their little useless wing stumps vestigial remnants.  Examples of this include the ostrich, kiwi and penguin.


Parts of the human body that are vestigial remnants include the appendix, extra nipples, tailbone, Darwin's tubercle, and even goose bumps. 
If  a species changes a lot or evolves rapidly it will have lots of vestigial remnants.  It will also have a lot of recently evolved traits.  Things that are taking the place of the things that are no longer needed. 
Humans used to have multiple nipples due to birthing numerous babies at once.  We evolved to birth singletons prematurely.  Extra nipples became a vestigial remnant.  Very recently fatty tissue has formed under the single nipple.  Newly evolved traits tend to be genetically fragile.  They tend to be more susceptible to malfunction.  This is why one in ten women will have breast cancer in their lifetimes.  The genetic material in the breast tissue is not sufficiently redundant to ward off malfunction.  Cancer rarely happens in primary heart tissue and when it does it is usually not malignant.  The heart has been evolving for a much longer period of time.
In regards to how we think, the parts of the brain that are recently evolved include the pre-frontal cortex and the angular gyrus.  These parts have less redundant circuitry and are more prone to malfunction.  Surely everyone is familiar with the multitude of ways our sensory integration can be fooled.  You can see a smattering of these at this website: Me of a Little More or Less Faith.  The dorsolateral pre-frontal cortex requires a rather complex cellular migration from the basal forebrain during the third trimester to form correctly.  Autism and schizophrenia are theorized to possibly result from incorrect or incomplete migration of these cells. 
I bet that there are lots of humans whose newly evolved pre-frontal cortexes may not have totally formed right.  What do you think? lol
In addition to increased susceptibility to anatomical disturbance, these brain structures also lack functional wherewithal.  Deeper and older brain structures that run our autonomic nervous system usually function pretty well under most conditions but our dorsolateral pre-frontal cortex can be taken off line very easily.  The ability to think rationally suffers due to fatigue, intoxication, anxiety or anger?  This is why you can't think rationally when someone insults your wife in a bar at 2:00am?
The part of the brain that does sin is recently evolved.  It is more susceptible to malfunction.  It is why Christians must work so hard to force themselves to not sin. 
There is another explanation. 
I would suggest that evolution creates in our species genetic modifications that do aberrant behavior.  New mutations that have survival value increase in a group.  Aberrant behaviors arise not just as pathology but as adaptive genetic changes.  This happens a lot in a species such as ours when it undergoes intense selective pressure. 
Some of this aberrant behavior is injurious and some of it is not.  We are also programmed to not tolerate aberrant behavior of any kind in order to have stronger social unity.  On a percentage basis this often protects the group but sometimes it causes hurtful behavior.  It can cause prejudice and discrimination to individuals for behavior that is not logically hurtful.  Like homosexual behavior, for example. 
We need to have ingrained restrictions on our behavior because we often want to do behavior that is left over from our hunting/gathering past or is aberrant due to recent genetic modification or illness.  We must not do these behaviors because they are often injurious to others.  I am also thinking life would not be very fun if the government had to go around forcing us to not do these things. 
I am pretty sure that the civilizing process will eventually correct those behaviors that should not be on the list of sins.  Of course, cultural change takes time.  My suggestion is that we promote education so that progressive ideas and values can change our society for the better.  It would be nice if old ideas of what is, or is not, a sin could be updated as we learn more about ourselves.  However, in the end we will need to maintain a set of morals of some kind in order to more easily govern a large society.  Sorry if I am suggesting that we see it both ways.


In conclusion, we are the only species that is able to think outside our innate programming to such a significant extent.  We are the only ones that make a conscious effort to keep from doing some of our innate and/or aberrant behavior.  This kind of thinking allowed us to adapt more quickly to a changing environment and is, quite possibly, the reason we are the only hominids that survived. 
I hope that my orthodox priest does not think that I have sinned by saying all of this or that my dorso-lateral pre-frontal cortex can think outside my programming enough not to care or that this can keep my wife thinking that I do care.  Help me on this, Phil.

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