Key points for what neuroscience teaches us about human nature:

• Human newborns come into the world “incomplete”, and are much more weaker, and more vulnerable at birth than other animal species

• The classic debate about Nature versus Nurture, can be reframed by developmental neuroscience: Our “nature” is our ability to be shaped by our respective environments (e.g. our “nurture”)

• The neural mechanism that provides this is neuroplasticity; the developing human brain is extremely malleable, and is profoundly shaped by early experiences and environments

The baby giraffe, weighing as much as 150 lbs, can stand and walk within the first hour of it's life. The baby pig can start walking just minutes after birth. The baby iguana? Moments after hatching it can leap into a full-out sprint to avoid predators. 

The abilities of young animals can be awe-inspiring. How do the skills of the young human stack up?

If you've spent any time around human newborns, you'll be hugely underwhelmed. It's a lot of crying, a lot of diaper changes, and very little resemblance to the abilities of adult humans. They can barely lift their own heads, let alone walk. 

Compared to other animals, human nature has some very humble beginnings. 

But from this humble starting point eventually comes the incredible sophistication, talent, and mastery that defines the human condition. All human exceptionalism, in all of its richness and diversity, stems from the same modest starting point. 

How do we get there? When we examine the question of human nature through the lens of neuroscience, a compelling picture emerges. It suggests that the often incredible abilities of adult humans are inextricably linked to this "incompleteness" at birth. 

How does the developing brain ultimately take on these skills and abilities? And what can this neuroscientific perspective teach us about the essence of human nature? 

Let's dive in.

Developmental Neuroscience and Human Nature

The first thing to note is fairly obvious: compared to newborns, who are all relatively similar, adult humans differ tremendously. We come to hold a range of incredibly specialized skills and aptitudes. Some become astronauts, while others become rappers, athletes, etc. Some speak Japanese, while others speak sign language, or English, or speak many languages. You get the idea. 

This basic observation poses a difficult question: How can we ultimately come to take on such incredible specialization, when our starting place, as newborns, is so unspecialized? 

This brings us front and center to the age-old debate in developmental neuroscience about Nature versus Nurture. 

On one extreme view, we're born as blank slates: everything we come to understand in this world, from emotions, to concepts, to language. The shape and growth of our bodies may be genetically determined, but the contents of our minds are not. Nothing is predetermined. Here, culture, experience, and socialization play a complete, and determinist role in cultivating our inner lives. 

At the other end of the spectrum, it's all innate. The essential features of our adult self are already genetically specified at birth. This includes our abilities and aptitudes, intelligence, and personality. Even a predilection towards being a musician, as opposed to being an accountant, or some other profession, is ultimately an element of our genetic endowment. In this view, development is merely the process where these inborn features are polished and expressed. 

While most neuroscientists and developmental psychologists will agree that the answer lies somewhere in between, the debate - especially about contentious topics like intelligence, rages on. 

However, from the perspective of human nature, these two forces may be much more complimentary than the debate typically poses. To whatever extent that the environment can shape features of our adult selves (e.g., nurture), it's fundamental nature of the human brain. 

Let's unpack this. 

Humans, as a species, didn't evolve many specific traits or tendencies. Unlike the Iguana, which can rely on pure, genetically imprinted instinct, to sprint away from deadly predators moments after it has hatched, human beings have very few specific behaviors, pieces of information, and tendencies, which are present at birth. 

What we are born with is maximal flexibility. We're born with an openness, unlike any other in the animal kingdom, to be shaped by the specific features and experiences presented to us in our environment. Our specialization is the sheer capacity for learning and malleability.  

In this view, the biggest contribution of our nature is that we are shaped so profoundly by our nurture.

Human Nature and Human Evolution

One interesting line of evidence for this view comes not from modern neuroscience, but from anthropological investigations of ancient humans during a critical period in our evolution. Research spearheaded by Rick Potts of The Smithsonian's Human Origins Program, finds that early humans faced unique, and intense evolutionary pressures. 

Food resources were scarce and highly variable, the climate swung rapidly from season to season, and a wide range of large predators was an ever-present feature of life. The throughline of all of these challenges was variability in the environment: early humans, during this time, could only afford to rest on their laurels for a short time. One season, they would need to catch fish to get by; but the next season or two, they'd need to hunt, or forage for berries. 

Coupled with the ever-changing weather and the dynamic threats predators face, there was no one lifestyle solution to settle into. Thus, forged through these environmental pressures, our distant ancestors, slowly evolved this incredible capacity for change. Instead of developing a specific set of characteristics suited for a particular environment, these early humans evolved the capacity to adapt to whatever came their way. 

Simply put, the human brain evolved for flexibility, itself.

Human Uniqueness through Neuroplasticity

Humans are born incomplete, and of any other creature, molded most significantly by their specific environment and set of experiences. But what precisely about the brain - especially the developing brain- makes human beings so open and uniquely adaptable? What is this natural feature of the human brain that provides this? 

Fundamentally, this comes down to neuroplasticity. 

Neuroplasticity is the brain's incredible ability to be shaped by experiences and adapt following injury or ailment. It is the flexibility of the physical brain, which enables it to change and evolve as we go through life. 

Neuroplasticity is the basis for all human learning. Without this malleability, the brain would be unable to retain new information, create new memories, or improve our skills. 

While neuroplasticity persists throughout the lifetime, it is a much more robust feature of the young, developing brain. This is why learning, especially for implicit skills, is much easier early in life than later. Young children learn languages, for example, far better and more quickly than their adult counterparts, and they do so with little apparent effort. 

By just two and a half years old, toddlers know up to 1,000 words in their native language, and can communicate substantial ideas. Moreover, children growing up in bilingual or multilingual environments will learn each language relatively easily. In contrast, if you've ever tried to learn a new language after your 20s, you know it's much more arduous. 

Language learning is but one of many examples of developmental exceptionalism. Consider learning a new skill, such as a sport or instrument. These are undoubtedly much easier to master as a child, than to try and pick up as an adult. The same 1000 hours of learning are much more fruitful as a child than as an adult. 

Our ability to learn by leaps and bounds as a young child is owed to the plasticity of the early, developing brain. 

Final Thoughts on Neuroscience and Human Nature

When it comes to life's early moments, we don't exactly hit the ground running. The human newborn, especially compared to other animal counterparts, is weak, unskilled, and vulnerable. 

But as we've seen, this weakness is a hidden strength. 

In all of its apparent weaknesses, human infancy isn't something we overcome on the journey to becoming talented adults. It is, in fact, the very thing that enables these talents to develop in the first place. 

Photo by Alex Hockett on Unsplash

References for “What Neuroscience Teaches Us About Human Nature”

Antón, S.C., Potts, R., and Aiello, L.C., 2014. Evolution of early Homo: An integrated biological perspective. Science 345(6192): 1-13.  doi:10.1126/science.1236828

Costandi, M. (2016). Neuroplasticity. MIT Press, Cambridge, MA.

Mundkur, N. (2005). Neuroplasticity in children. The Indian Journal of Pediatrics, 72(10), 855-857.

Owen, R.B., Renaut, R.W., 2018. Environmental dynamics during the onset of the Middle Stone Age in eastern Africa, Science.

Pinker, S. (2004). Why nature & nurture won't go away. Daedalus, 133(4), 5-17.

Pinker, S. (2013). Language, cognition, and human nature: selected articles. Oxford University Press.

Potts, R., and Faith, J.T., (2015). Alternating high and low climate variability: the context of natural selection and speciation in Plio-Pleistocene hominin evolution. Journal of Human Evolution 87: 5-20.

Potts, R., Dommain, R., Moerman, J.W., Behrensmeyer, A. K., Deino, A.L., Riedl, S., Beverly, E.J., Brown, E.T., Deocampo, D., Kinyanjui, R., Lupien, R., Owen, R.B., Rabideaux, R., Russell, J.M., Stockhecke, M., deMenocal, P.,  Faith, J.T., Garcin, Y., Noren, A., Scott, J.J., Western, D., Bright, J., Clark, J.B., Cohen, A.S., Keller, C.B., King, J., Levin, N.E., Brady Shannon, K., Muiruri, V., Renaut, R.W., Rucina, S.M., Uno, K., (2020). Increased ecological resource variability during a critical transition in hominin evolution, Science Advances, vol. 6, eabc8975.