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A defining feature of the modern era is its rate of change. The cultural world around us is shifting rapidly. So much so, that our minds and bodies can barely keep up.

It typically takes generations for genes to change, with small adjustments being made with every person born. They seldom have the ability to change and adapt over our lifetimes, making it difficult to adjust to modernity.

However, we have inherited genes that code our brains in such a way that we can adapt through learning. Our brains can change in response to experience and the environment. This is known as neuroplasticity and humans are especially good at it.

Let’s look at what makes us so great learners and some tools we can use to accelerate that adaptability.

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  The Adaptive Scholar

Neuroplasticity (How YOU Evolved To Learn)

What is it that makes us human? Many of the most prominent figures in anthropology and the social sciences argue that it is culture – our propensity to construct material objects, develop ideas, and pass traditions down to subsequent generations. Our capacity to collectively engage in common practices, both materially and idealistically, is unmatched. We can be molded at a young age to adopt nearly any habit bestowed upon us by our parents. We are a socially learned species.

That being said, there is a biological substrate that permits us to learn any and all cultural traits – neuroplasticity. Neuroplasticity is the brain’s ability to change in response to experience and the environment. To understand how this works, here is a quick and dirty crash course on the science behind neuroplasticity. 

Crash Course on Neuroplasticity

The brain is composed of cells called neurons. Neurons communicate with each other through chemical signals, and the point where two neurons meet is called a synapse. When certain chemicals are sent between neurons in specific parts of the brain, certain experiences are felt. For example, when you eat a piece of chocolate, the neurochemical dopamine is produced in the lower part of the brain and sent up to the reward, pleasure, and motivation center of your brain, giving you that “feel good” sensation.

When neuroplasticity occurs, neurons and their connections change. There are generally three ways this can occur. First, new neurons and connections can be made. Second, old connections can weaken or be “pruned” of their connection entirely. Third, present connections can be made stronger. Without these alterations, our brains would be rigid and incapable of learning. Luckily for us, this is not the case.

Instead, our brains are dynamic entities capable of learning and modifying their structure and function to better adapt to their environment. Our thoughts and behaviors change as a result. 

It has been shown that most mammalian brains actually do have the capacity for neuroplasticity [1], and clearly, they are capable of learning. So, what is it that makes the human brain so special and so susceptible to enculturation?

The Human Brain

According to evolutionary neuroscientists Chet Sherwood and Aida Gomez-Robles, the human brain evolved to be unusually plastic: 

In a review of the literature, they came away with 3 aspects of the human brain which suggest that natural selection shaped it to be more plastic [3], thus making it better adapted to cultural learning.

First, humans are born altricial – helpless. We have essentially no instinctual survival skills for the first few years of our lives. We are born less mature than most animals, including other primates. This means that a greater percentage of our brain development occurs after we are born. Therefore, the human brain is given more time to develop under the influence of social conditioning. We are dependent on adults when we are young, but that dependence is accompanied by cultural learning. 

Second, we have protracted synaptogenesis and myelination. In other words, our brain’s ability to make new connections and strengthen old ones is extended later into life, beyond adolescence. Chimps are similar, but our brains are able to do so even later in life and make more complex connections partly because they are about three times the size of a chimp’s. 

Third, our genes express qualities that promote plasticity. For example, since our separation from chimpanzees 6 million years ago, we have acquired a gene called SRGAP2C. This gene is associated with slowing down changes in neuron structure, giving the brain more time to mature. Another is the FOXP2 gene, which is crucial for the development of human speech. When scientists express this gene in mice, it increases neuroplasticity. 

Given that we have likely been gifted with great neuroplastic potential by natural selection, how can we leverage this to increase our ability to learn and adapt our behaviors to our ever-changing environments?

Insights From Neuroscience

Earlier in the article, I mentioned how specific neurochemicals moving between the brain’s neurons lead to specific effects. In terms of triggering neuroplasticity, the two most important chemicals are called norepinephrine and acetylcholine. 

Norepinephrine is associated with alertness, arousal, and attention. As it relates to neuroplasticity, the increased attention triggered by norepinephrine places a spotlight on whatever you are experiencing. Acetylcholine highlights what happened during that aroused state and marks the neurons associated with it in order to reinforce their connections later. 

This process of reinforcement makes those neurons more likely to fire in the same sequence again in the future, making whatever behavior you enacted or skill you engaged in more reflexive. It is what allows for learning, regardless of what it is you’re learning.

There is one caveat, though. The act of plasticity itself does not occur while we are engaged in any experience. In fact, it doesn’t even occur when we are awake. Norepinephrine and acetylcholine mark the neurons that will be reinforced, but the actual reinforcing only happens while we are asleep. 

Sleep is a Tool for Plasticity

Evolutionarily, this all makes sense. Compared to today, learning was more closely tied to survival for our human ancestors. They weren’t learning to code, they were learning how to find their next meal or avoid getting eaten by a saber-toothed cat. It was vital that they were hyper-alert in these high-stress moments. Additionally, it was likely advantageous to delay allocating neuronal resources to plasticity until after the intense experience and arousal levels were at their lowest – i.e., sleep.

It is well known by the science and medical community that sleep is essential for mental and physical well-being. Now, we know that it is necessary for our plastic brains to reinforce what they have experienced throughout waking life. This brings me to another point discussed in an earlier article on the evolution of human sleep.

The sleep intensity hypothesis suggests that ancient humans evolved to condense their sleep to shorter time spans once they transitioned to sleeping on the ground [4]. This is because they had to be more alert to large ground predators and other human groups. The use of fire at night likely also encouraged them to stay up later and socialize.

Natural selection therefore favored shorter bouts of high-quality sleep over longer durations that put humans at a greater risk of predation. This adds more support to our unique propensity for neuroplasticity. If we evolved more efficient sleep, and sleep is essential for neuroplasticity, could this have been another reinforcer that promoted the plasticity of the human brain throughout evolution?

Conclusion

By changing itself in response to experience, the brain is a tool that allows us to adapt to our environment through learning. The human brain is distinct from that of other animals because it evolved to be especially prone to neuroplasticity – the mechanism through which learning occurs. This has enabled us to learn from our social milieu from an early age and develop complex cultures. 

To leverage neuroplasticity in your own life, as a means to enhance learning, it is necessary that you check these two boxes:

1. Increase your alertness and attention before or during the bouts of learning.

2. Get proper sleep after that period of learning, in order for the associated neurons to build stronger connections. 

You can naturally increase your alertness before or around a bout of learning by doing things like a quick workout or taking a cold shower. It must be something that elicits an excitatory response from your nervous system - something that wakes you up. Even caffeine will work.

To achieve better sleep, I will refer you to my video on the subject. There, I highlight some tips and tricks to achieve better sleep based on behavioral evolution and modern sleep science.

References:

[1] Most nonhuman studies have been done on mice, rats, and other primates:

• Kempermann G., et al. 1997. “More hippocampal neurons in adult mice living in an enriched environment.” Nature 386:493-495.

• Kornack D., et al. 2001. “The generation, migration, and differentiation of olfactory neurons in the adult primate brain.” Proc Natl Acad Sci USA 98:4752-4757.

• Kuhn H., et al. 1996. “Neurogenesis in the dentate gyrus of the adult rat: age-related decrease of neuronal progenitor proliferation.” Journal of Neuroscience 16:2027-2033.

[2] Gomez-Robles, A. and Chet C. Sherwood. 2015. “Human brain evolution: How the evolution of brain plasticity made us a cultural species.” Mètode Revista de difusió de la investigació 7:7.

[3] Sherwood, Chet C., and Aida Gomez-Robles. 2017. “Brain Plasticity and Human Evolution.” Annual Review of Anthropology 46 (1): 399-419.

[4] Samson, David and Charles Nunn. 2015. “Sleep intensity and the evolution of human cognition.”Evolutionary Anthropology 24(6):225-37.

Fit Fuel Song Suggestion

The Fit Fuel song suggestions are hand-picked by yours truly to elicit the motivation (and possibly aggression) needed to initiate or persist through a grueling workout. They consist of heavy, brutal guitar riffs and gruesomely guttural vocals. Additionally, I timestamp what I believe to be the best riff of the song - one that will kick your nervous system into overdrive when approaching a personal record (PR).