July 1, 2020

The Human Marvel – Lessons in Intelligence from Human Physiology

By Deeptha Medhavan, MSc in Molecular Biology

In today’s digital world, one often hears the term ‘smart’ associated with machines that make our life easier. A ‘smart’ refrigerator can use an in-built camera to remind you when you’re out of milk. A ‘smart’ phone can offer greater computing power than the supercomputer that sent astronauts to the moon. We are building ‘smart’ robots that can learn from the environment and solve problems without any human intervention. But what is exactly meant by the word ‘smart’, and is its use appropriate here?

HOW DO WE DEFINE INTELLIGENCE?

Traditionally, intelligence has been measured as the possession of knowledge. However, there is no real consensus on how humanity defines ‘smart’.  In engineering, intelligence is the capability to problem solve, while a stock trader would equate intelligence with the ability to make decisions under undue pressure. In evolutionary biology, intelligence is the ability of an organism to adapt, survive and thrive in challenging environments. Among the diverse species that inhabit the earth, humans have generally been considered the most intelligent. We do not have the predatory stealth of cheetahs or the sheer strength of elephants. Nor could we have compared with the colossal size of the ancient dinosaurs. Yet, it is our kind that has managed to colonise the planet with a strength of over 7.3 billion.

THE HUMAN BRAIN – LEADER OR TEAM PLAYER?

Science and Philosophy have tended to focus on the capabilities of the human brain as the sole reason for our success on this planet. The brain’s status isn’t unwarranted – no machine on earth could compete with the human brain’s repertoire. Yet, when we dive deeper into the human body, one can see, every cell of life is a sophisticated living machine, capable of performing a myriad of complex tasks within a millisecond. Working together, these cells are capable of functioning as a camera, a thermostat, a motor, a microphone, a combustion engine and a computer – all built into one. Contrary to popular thought, the brain isn’t an autocratic leader, merely transmitting instructions on what needs to be done. Like any well-functioning organisation, each cell regulates its own internal processes, working in perfect harmony with other cells, as the brain watches over.

The helical DNA molecule is the cell’s operation manual, storing millions of years of knowledge about the processes that sustain life in the form of a simple four-lettered code. However, a smart machine isn’t one that simply runs through a specific set of instructions. The cell must also be prepared to respond to unexpected circumstances. The instruction manual does not encompass all possibilities of accidents, errors and pathogens. Instead, the cell resorts to an ingenuous, yet, simple strategy: teamwork. Each cell is integrated with signal systems that are constantly in contact with other cells, organs, organ systems and the external environment. Together, the cells manage to achieve what they individually cannot.

HUMAN MOTION – A PRODUCT OF TEAM WORK

Consider a human being walking down the road. He is late, veering through heavy traffic to make it to work on time. Emotions are running through his mind, stress, worry and guilt. Hundreds of thousands of neurons in his brain light up as memories of previous encounters with his boss flash through his mind. As he focuses on getting to work, millions of cells in his body toil in the background, unconsciously performing complex tasks.

The eye scans the road, taking in information about the path ahead. Images captured by the retinal cells of the eye are transmitted in the form of electrical signals via the cells of the optic nerve to the cortical neurons in the brain. But wait, the signal must now pass through multiple regions in the Basal Ganglia before the man even makes a decision to move a limb. The brain receives thousands of signals and not all instructions are worthy of being executed. If a signal manages to sustain this rigorous selection process, it must now be transmitted back to the muscles. Now the signal must transverse through the neuronal cells of the spinal cord which are integrated with the muscular cells. Depending on the muscle that needs to be moved, the signal undergoes a secondary selection process in the spine, with the left portion of the spine controlling the muscles in the right and vice versa. For an action such as walking, muscles on both portions of the body must coordinate with each other in order to achieve balance.

The muscle contains two unique sets of cells; Actin and Myosin. These cells move against each other by virtue of contraction and expansion. Thousands of fibres in muscles containing bundles of myosin and actin perform the same function with more coordination than a ballet dancer, thus facilitating movement. These complex pathways only encompass a simplistic pattern of walking . However, the man walking down the road will also encounter multiple obstacles. The man must consistently adjust his path depending on other passers-by on the road, potholes, vehicles and other obstructions. Therefore, there is a constant flow of information between the eye and the brain.

Within milliseconds, the brain must calculate the approximate speed of the obstruction, distance to the obstruction and potential options for path correction to avoid collision. The heuristic processes by which the brain achieves this is so complex that they are yet to be fully understood. However, it is generally agreed that humans adjust the direction of their movement before adjusting speed. The degree of adjustment depends on information collected by the cells in the eye – even a slight miscalculation can result in major accidents.

ADAPTING TO THE UNEXPECTED

These processes only describe conscious movement – the process by which the brain plans and executes movement. The muscles can also execute reflexive movement without any interference from the brain. Consider a car speeding through the road, crashes into the vehicle ahead, distracting the man from his contemplation. Reflexively, the cells in the lower limbs facilitate movement away from the sound, because they have learned from past behaviour in similar circumstances. As the man moves away from the noise, his eyes begin collection information about the scene, as the brain makes a decision regarding his next course of action.

During unexpected situations, the pituitary gland is stimulated to secrete adrenaline which quickly moves through the body recruiting diverse cells from distinct organ systems. The lungs begin contracting and expanding quickly, taking in more oxygen from the environment. Reflexively, the muscles in the jaw facilitate the opening of the mouth to maximise oxygen absorption. The cells of the digestion system shut down to divert more resources to the muscle. The cells of the eye become focused, ignoring stimulus from other regions of the environment to solely focus on the accident scene. The skin cells and associated neuronal networks become desensitised in order to reduce pain felt by the man. The cells in the heart coordinate faster pumping, to promote oxygen delivery to the muscles that need to move. The cells in the muscle jump into action, steering the man into motion.

As complex as these processes seem, they all occur within seconds, rarely inhibited by error. A popular adage states that while non-living objects such as crystals become less interesting when seen through a microscope, the human body only seems more wondrous as we zoom in. Although our species has achieved many great things on the planet, we have never managed to replicate the brilliance of the human living body. Over millions of years, by sheer trial and error, the it has evolved into a remarkably intelligent set of systems, where the whole is more than the sum of its parts. We have developed so many tools and machines by replicating living organisms, such as air planes by contemplating how birds fly, musical instruments by understanding the human vocal cords, cameras by learning about the human eye, to mention a few examples. Almost everything we have built we have learned from nature and the way it works. There is no reason why organizational leaders cannot extract lessons in teamwork, coordination, synchronisation, innovation and adaptability by contemplating the vital intelligence of the human body.

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