Learning By Doing
It's amazing —stunning, actually — how quickly the brain can adapt. A really wild example of the brain's adaptivity is growing a third arm. You can actually do this at home [1]. To grow a third arm, you will need the following supplies:
- An accomplice
- A rubber hand
- A small brush
- A blanket or towel
- A very sharp knife or hammer
First, place your real hand and the rubber hand next to each other. Then, cover up your arm with the blanket so only the hands are visible. Then, have your accomplice use the small brush to stroke both the real and fake hand at the same time. Do this for a minute. This step is crucial because you are creating a conflict in the brain that it must eventually resolve. In the final step, have your accomplice threaten the rubber hand with the knife or hammer. If the brain successfully completes the remapping, then you will withdraw your real hand because your mind has taken ownership of the fake hand [2]!
The Adaptive Brain
The "rubber hand illusion" isn't just a fun parlor trick to play with your friends at Halloween. Neuroscientists have figured out how get people to rewire their brains so they can control a third robotic arm [3].
These stunning demonstrations show how remarkably adaptable and resilient the brain is. This adaptivity is analogous to the mechanism the mind uses after suffering a trauma. For example, if a specific region of the brain is damaged, then it has some capability to accommodate that trauma. In extreme cases, the brain will adapt by overtaking adjacent tissue so the individual can regain some of their original functionality.
What are the specific neural mechanisms for these adaptations, and what are some real-life implications?
Adaptivity and Late Bloomers
In a previous post, we learned that executive functioning (EF) is situated in the pre-frontal cortex (i.e., part of the brain just behind the forehead). Given its centrality to higher-order thinking, it is surprising to learn how late executive functioning develops. During young adulthood, the brain undergoes two important processes: synaptic pruning and myelination.
Synaptic pruning sounds horrifying, but it is a necessary process whereby unnecessary synapses (i.e., the connections between neurons) are removed.
Myelination is the process of adding a layer of lipids (or fat) to the outside neuron. The purpose of myelin is to speed up neural transmission. It's analogous to adding insulation to an electrical wire.
By most estimates, the frontal cortex isn't fully myelinated until a person reaches 25 years of age. That might explain why teenagers and young adults don't always make the best decisions. Their brain is still developing in the most critical region for planning, organization, response suppression, and (perhaps most importantly) counterfactual thinking!
The Classroom Connection
Understanding the timeline for neural development also has an important implication for education. Some students are late bloomers and need extra time for their frontal lobe to fully develop [4]. To give these students the time they need, there should be some flexibility in their educational timeline. Taking a "gap year," traveling abroad, or enrolling in AmeriCorp might be precisely what these students need. Not all students should be expected to rush directly from high-school to college.
In closing, we owe our brains a great debt of gratitude. Being adaptive and flexible is what makes us who we are. And who knows...maybe someday "being who we are," might include controlling a third arm. 💪
Share and Enjoy!
Dr. Bob
Going Beyond the Information Given
[1] The illusion of owning a third arm [link].
[2] Threatening a rubber hand that you feel is yours elicits a cortical anxiety response [link].
[3] Penaloza, C. I., & Nishio, S. (2018). BMI control of a third arm for multitasking. Science Robotics, 3(20).
[4] Karlgaard, R. (2019). Late Bloomers: The Hidden Strengths of Learning and Succeeding at Your Own Pace. Broadway Business.
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