To What Extent Are We "Hard-Wired"?

Synapse #7: It's time to let go of our supposed evolutionary baggage

Just about anyone who has come into contact with popular neuroscience and psychology has surely heard of the trendy notion that our brains "hard-wired" in certain ways. A simple search of "hard-wired" in Google News demonstrates how pervasive this idea is: 

Let's dig into that last link. Here's a quote: 

It makes more sense then to see traits such as cooperation, egalitarianism, altruism, and peacefulness as natural to human beings. These were the traits that have been prevalent in human life for tens of thousands of years. So presumably these traits are still strong in us now.

This is the classic argument so often presented: that although the world around us has changed drastically in the last 5,000 years, our brains haven't and that is why we are ancient brains living in a modern world. 

It's easy to see why this argument is so popular. For one, it's intuitive. Evolution occurs incredibly slowly. That's why it took so long into human history to discover it, and it's one of the many reasons people today deny its existence. If evolution occurs slowly, then our biology is likely extremely similar to the biology of ancient humans. 

I think these "hard-wired" arguments are also popular because they subvert our responsibility for our own behavior, and it can go both ways. For behaviors we feel guilty about (such as prejudice and racism) "hard-wired" arguments offer excuses for immoral behavior. Similarly, for behaviors like altruism, "hard-wired" arguments let us point fingers away from ourselves and instead at systems and institutions which have supposedly betrayed our natural tendencies. 

A common thread in the above links is that the trait which is supposedly "hard-wired" is whichever trait fits a narrative—it's racism of we're talking about mass incarceration or cooperation if we're looking to inspire institutional change. 

Yet, in my view, none of these "hard-wired" arguments seem to have any respect for our developmental potential, our changing brain, and the complexity of human behavior. 

Our Changing Brain

It's probably obvious to most that a child's brain has the capacity to change, develop, and adapt to his or her environment. As just one example, a child's prefrontal cortex, when compared to adults, is very underdeveloped—leaving a typical child less effective at making complex, rational decisions. 

Yet, in the past few decades, neuroscientists have begun to have a much deeper appreciation for the adult brain's capacity for change—a term known as "plasticity." For example, we now know that adults too grow new neurons in certain areas of the brain and that the brain undergoes profound differences throughout one's lifetime. 

Imagine for a moment that the neurons in your brain are a series of connected roads, crisscrossing and linking to each other in a web. The neurons in your brain undergo changes in two prominent ways. 

First, the intersections between roads are either formed or lost in a process called synaptic plasticity. Some intersections become stronger and more efficient, such as a cloverleaf interchange between highways. Others become weaker—maybe a four-way gravel road with a flashing red light. 

Second, the capacity of each road can change; some become 6-lane highways and others two-lane streets through a process of myelination that is performed by the supportive glial cells that I wrote about in a previous issue.

These processes are happening constantly throughout childhood and into adulthood. It's believed that these processes influence our affect, character traits, and of course, behavior. None of what I described is compatible with the notion of "hard-wiring" in our brain. 

It's time to give up our supposed evolutionary baggage

The problem with the "hard-wired" argument is that it is inherently rigid and doesn't leave open the brain's capacity to adapt and environmental influences. From Barbara King at NPR

A big problem with words like "hard-wired" and its familiars is their fuzziness, particularly in regard to what they might imply about the human capacity for learning and change. 

One common argument amongst evolutionary psychologists is that our brains are hard-wired to feel more empathy toward people within our own tribe—our own social status, race, sex, etc. This trait stems from an ancestral world in which it would be advantageous to vigorously protect your own group and be suspicious of difference which may introduce conflict. Indeed, I can understand this line of thinking—it is very difficult to extend compassion beyond our close inner circle, people who share our experience. 

But this fact doesn't abrogate me from the practice of intentionally mixing with groups from different backgrounds and certainly doesn't provide any evidence of a "hard-wired" opposition to difference. Feelings of love and hate are "triggered under given circumstances, facilitated or hampered by social conditions and structures" (Anthropologist Patrick Clarkin). 

In fact, there is strong empirical evidence of our social group's influence on our view of others—not our brain’s hard-wiring. Psychologists Thomas Pettigrew and Linda Tropp carried out an extremely extensive meta-analysis of over 1,400 papers that analyzed the effects of intergroup contact that found that an astonishing 94%of the studies examined showed that increased intergroup contact was associated with less prejudice. An association is, of course, not exactly a causal link. Yet, impressively, the study ruled out the possibility of a reverse causal sequence, publication bias, and other alternative explanations to put forth the most substantive evidence to date that it is our social structure, not our inherent biology or "hard-wiring" which influences our prejudice. 

It goes without saying that this is an extremely complex and nuanced topic. There are certain aspects of human nature that are surely inherent—such as those which are inherent in the genetic code itself—I would just urge you to think critically about popular arguments that attempt to portray your brain as already formed, ancestral, and incapable of change. 


🔗 Links

Follow Up: Neuralink

Last week, I linked to Elon Musk's Neuralink—a nickel-sized metal disk that acts computer-brain interface and is capable of recording and, eventually, manipulating neurons in your brain. Musk boasted about Neuralink's potential as not only a solution to diseases like depression and anxiety but also as an integrator of the power of AI and the human brain. 

Well, it turns out some neuroscientists are concerned that "the cool factor clouds critical thinking." Moreover, Neuralink might be an impressive proof-of-concept from a technological standpoint, but it's important to remember that it is only one piece of a complex solution to neurological diseases that will need to include parallel work in molecular medicine and neuroscience


Neuroscience Needs Some New Ideas. Nature recently reviewed the book The Idea of the Brain by Matthew Cobb which summarizes the history of ideas about the brain. I plan to read the book eventually, but the big idea here is the profound impact that metaphors have on science. "Metaphors change how science is done, by licensing new interpretations or inspiring new experiments." and how metaphors "conceal as much as they reveal." As just one example: it is preposterous to make any assumption about how the brain actually works based on how computers work, yet we are seemingly trapped in this false metaphor because of misleading metaphors and language such as how brains "compute" or how neurons "encode" information. Just look at how the Neuralink website describes neurons:

It’s true that metaphors are intended to facilitate understanding amongst non-specialists, but the consequences are that even specialists find themselves trapped in this false thinking that prevents entirely new paradigms of understanding in science.


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