Nature vs. Nurture: Scientific Models and Their Importance to Neurological Conditions

It’s not surprising that humans would want to understand why we are the way we are. Our curiosity is one of our greatest strengths after all. We chip away at our understanding of the world by asking questions about why things are the way they are, developing hypotheses based on our current understanding, then conducting experiments to validate or refute those hypotheses. This process of curiosity, inquiry, experimentation, and validation is fundamentally critical for the advancement of science and medicine. But our understanding of any given research question is not perfect or comprehensive. 

To account for this gap, we develop scientific models, which reduce the complexity of a research question into simpler frameworks. These models aren’t perfect nor do they intend to be; they exist as stopgaps until further revelations are unveiled. Some models become entirely undermined by an alternative theory. Does this mean the model was a failure? Not at all; in fact, the now-refuted model itself was likely necessary to generate those insights. One such scientific model that once was the backdrop for heated discussion in psychology, neuroscience, and biology was the nature versus nurture model, which posited that the sum of who a human is in a given moment is either entirely due to their innate genetics (“nature”) or their environment (“nurture”). In contemporary research, the model is much more complex and posits the interplay of our genetics and our environment explains so much more, and it explains things much better. This is the nature of scientific models and they advance science. 

A major hurdle that must be accounted for whenever considering scientific models is the human element of science. Science can be dogmatic; or rather, since science itself is not a thinking organism any more than gravity, it’s not science that can be dogmatic but the people who practice science. No one scientist likely believes they’re dogmatic or inflexible, but science as a framework is dynamic. Science is like the ocean; when you look at the ocean, you see one body of water with no separation between the individual water particles but the water you see when you look at the ocean today is comprised of different water particles than it was the time you saw it a year ago. The ocean hasn’t changed, and semantically speaking, it’s the same ocean you saw a year ago, but the particles are still not the exact same ones. Our definition of the ocean is fixed in this example so the underlying particles that comprise the ocean don’t figure all that much into how we define the ocean. Science, then, is like the ocean with individual scientists functioning as the particles in this example. The important distinction is that each individual water particle behaves identically to another due to the fundamental nature of how a water particle is defined (as the covalent bond between two hydrogen particles and one oxygen particle). Any two scientists, even if they agree on a specific research question, are never going to behave or think identically all the time. So while science is a framework, the definition of science is informed by humans, and the practice of science can shift due to the shifting nature of the scientists who practice science. This demonstrates the relational components of any scientific question. This is also where dogma can become problematic because science is in and of itself not a pursuit of certainty but the pursuit to narrow the gap between what is understood and what isn’t. Science works every day to confront what we have come to believe as certain because we know there is always more to learn. 

These ideas are the fabric of knowledge. Science challenges convention and what is currently understood, it’s never only science, but also philosophy. Historically some of the most prominent scientists in history were also philosophers who dared to question the very nature of the reality that others proclaimed as certain. We look upward at the stars to understand how we fit into the universe; inward to ourselves to contemplate questions of consciousness, being, morality, and ethics; and we look downward into deeper and deeper quantum realms to inquire about the minutiae material with which everything else emerges. This pursuit inward towards ourselves is no different than any line of inquiry; we wish to use the knowledge we gain through empiricism to explain the world around us. Sometimes that exists in the form of scientific models, or diagrams or axioms we use to remove complexity from reality to improve how we understand the more complex reality. Models are common across all fields of science, but they are easily spotted in weather reports. Meteorologic models take something as complex as oceanic and atmospheric conditions to predict the likelihood it’s going to rain in a specific area — but that specific area is affected by the patterns affecting other areas so there can never be certainty unless you can create a model based on every single factor that plays into rain in a specific area. No scientist is such an idealist that they expect to know anything with such precision that you can essentially understand every relevant particle in order to build a perfectly precise model for predictions. Not only is that not reasonable, it’s also not even possible. For a model — whether it’s a mathematical model or a set of axioms that explain a natural phenomenon — to be effective, it has to be realistic, accurate, reproducible, and empirically supported. The utility of scientific models relies on their ability to explain complex concepts in simplified ways that can be used to generate subsequent hypotheses and experiments. One such model that opened up important questions of morality, ethics, human behavior and so much more was the nurture vs nature debate.

This debate, if you’re unfamiliar, is a contentious one that still affects all of us today. What it comes down to is the essence of what causes what in terms of our behavior and who we are: Is it our genetics or our environment? Rarely if ever in science is there a binary with a clear-cut answer and certainly rarer so when the general consensus is that there is none. With who we are, it’s clear that our genetics and environments interact more than we had previously understood. There’s also the question of shifting societal norms, standards, and ethics. It’s common for people to want to explain a murder away as something that was inevitable due to somebody’s genetics, but this neglects far more complexity at play, and it also is scientifically unserious; if we don’t wish to understand why things happen — especially things that have an impact on other humans — we don’t advance understanding. It’s also important to consider that understanding these things is not ever only about understanding one thing; in the same way that there is an interplay of our environments and genetics, there is nothing in science that does not relate to many other important questions so every scientific inquiry has compounded importance directly proportional to the amount of other questions that involve the specific question. Every scientific inquiry is a web with differing degrees of relevance to other scientific questions. Bacterial infections, for example: There are many conditions where bacterial infections are very common. In these conditions, there tends to be a ton of antibiotic research, often producing compelling insights about antibiotics, bacteria, and bacterial resistance. So if a lab develops a new antibiotic due to researching a specific condition, is that new antibiotic only relevant to the community that inspired the research? Absolutely not; that antibiotic is important to anybody that is affected by that specific bacteria, which could possibly be the entire world. Collaboration is crucial in science, which is one reason why science is good at producing insights, and it’s why scientific consensus shifts when empirical evidence tips the scale to a more promising theory. Science does not usually produce a model and then support evidence that is diametrically opposed to the accepted model; it happens more that the accepted model is simply not complex enough, so a more complex theory which accounts for more factors and more empirical evidence is developed on top of the accepted one. These models, even if they are disproven, are still fundamentally important in the history and progression of science.

Often, people can neglect the true complexity of a research question. This can be found in the question “Why do humans do what they do and why are they the way they are?” A critical component of science is the question that’s posed; for any model to be derived from the question that’s asked, it has to be logical. Experimental design, outcomes by which to measure the question, the future research questions that come from this experiment; if the question is not posed correctly, the rest of the experiment fails. Should we seek to understand why humans act the way we act in the same way we seek to understand why some people get cancer and some don’t? It might be easy to say no—that doesn’t make sense because cancer is a biological condition whereas human behaviors are more subjective. That’s a fair point, but cancer is also informed by human behavior. Why do some people smoke cigarettes fully knowing it can cause cancer? It’s easy to either assume that those people fully understand the risk and simply choose not to care or stop, but then this neglects other human behavioral elements as well as other environmental aspects: Some people who smoke a carton a day for a decade don’t get cancer, why? To that end, nurture vs nature, which isn’t an accepted paradigm today, opened up a lot of important questions. Every research question affects everything else that hinges on that theory, and that theory is affected by all of its underlying theories. When the theories that uphold an accepted paradigm begin the collapse, so does everything above the now-collapsing foundational ideas, all of which will give rise to a stronger, more compelling theory. 

Our genetics are also not as immutable as we’d like to believe them to be. Some genes switch on and off in response to external or internal signals; our genes also affect each other, so as one is altered, so too are others. Gene therapy is complex for this reason; since gene expression can be regulated by other genes and environmental factors there can be unintended consequences to modifying one gene. We also know the brain has plasticity, which can both help and hurt people. Diet, environmental pollutants, pathogens can alter the structure and chemistry of our brain, but so too can meditation, medication, and the removal of harmful compounds. So while one might have a genetic proclivity toward something (“nature”), our environment (“nurture”) can either significantly push us in either a hurtful or helpful direction. Alternatively, our environment can shift and trigger gene expression. This idea that it’s either our environment or our genetics that wholly determines something ignores how our genetics and environment are not separate entities that affect each other, but that there is overlap and interdependence between our genetics and environment. Two different color liquids do not always blend into a third color; sometimes they separate based on densities; this is true of our genetics and environments too, in some cases, they act as two opposing forces, sometimes they act synergistically, and sometimes there is no interference at all. This model makes sense to people today but at one point, both sides of the model had strong proponents. 

Models are emergent from scientific inquiry; they serve to package knowledge in ways that can be visualized and understood in our minds in a more efficient manner. They are chapters in the books of scientific inquiry. They are everywhere in scientific research and they’re constantly evolving. The nature vs nurture debate is one that has played an outsized role in the history of neurological conditions due to the natural overlap of psychology and neuroscience. While human behavior is definitely important when we wonder about pulmonary diseases, our lungs are not our minds. Our minds, which are emergent from our brains, are then bidirectional in their interactions with our brains. Our minds are always thinking, and our brains are always giving rise to those thoughts; our environment is the world “we” occupy as our minds. Our bones exist in this same environment but our bones aren’t “thinking” as they undergo stress; our brains are. Our brains and minds are tricky; the placebo effect and our minds are capable of inducing biological systems. Anxiety is also reminiscent of this; just thinking about something that stresses us out can directly trigger a physiological response. This interplay means these questions of human behavior, psychology, and how all of this affects our nervous system are fundamentally important to understanding neurological conditions, especially those that have a movement or cognitive component. As we understand more about genetics and gene expression and how our brains and perceptions are affected by the environment — and how we ourselves can alter the environment — this will further our understanding of the brain and neurological conditions. 

As we gain further understanding of our brains and nervous systems, genetics, and the interplay between genetics and our environment, we can improve the models we currently have. With better models, we can better pose questions that inform scientific research. This is how science advances understanding, and with this overall increased understanding, we can develop better prevention, diagnostic, and treatment strategies.

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