The contemplation of two books, 'Breaking Through Depression' and 'The Balanced Brain'

Breaking Through Depression; The Balanced Brain – reviews | Health, mind and body books | The Guardian

I define depression as a side effect that occurs because humans, who have evolved to be suitable for running, live in a sitting-centered modern society.

The main causes of depression can be summarized into two main causes: poor blood circulation and stress. Wildfires are very closely related to humidity, so they occur intensively between January and May in Korea. Suicide is deeply related to blood circulation and occurs especially often between December and May. Depression is also physically closely related to poor blood circulation, and poor blood circulation is closely related to temperature, exercise, and posture. Mentally, excessive stress due to various reasons has a major impact.

Exercise, stress, and posture are not only individual problems, but also social and systemic problems. It is the fate of modern people who must live in a modern sitting-oriented society with a body suitable for the running-oriented society of the Paleolithic Age. Modern people still have a body suitable for hunter-gatherer life in the Paleolithic Age, and this body has been evolved to effectively control short and strong stress. As a way to overcome depression, creating an environment that is exposed to short and strong stress seems to be a good solution. Looking at statistical data related to depression, it can be observed that smartphones have shown a marked increase since around 2007, when they began to become popular.

In our body, sympathetic nerves are activated in crisis situations and parasympathetic nerves are activated in rest mode. However, if stress persists, both sympathetic and parasympathetic nerves are deactivated. Even when you rest, your body cannot recover properly. Therefore, the overall function of the body, including blood circulation, is naturally deteriorated, and depression is intensified.

It can be seen that society becoming safe is proportional to the degree to which the need to worry about survival-related food, clothing, and shelter problems is reduced. Eating less food seems to be one of the keys to longevity because eating less does not make the body's system lazy. In the end, it seems that society becomes safe can be interpreted as its members' body systems becoming lazy and less entertaining stimuli. Until the degree to which society becomes safe reaches a certain level, it contributes positively to human mental activities, but when it exceeds a certain level, it seems to contribute negatively.

Daily life centered on sitting --> Causing continuous low-intensity stress (sitting in a hunched position for long periods of time, studying/working, emotional labor, long-term discord, bullying, bullying, etc.) --> Depression --> Dysautonomia --> Decreased breathing --> Causes poor blood circulation --> Lack of sustained blood supply to some parts of the body --> Reduced physical activity --> Petrification of unused muscles --> Postural distortion and accelerated decline in physical function --> > Nervous system degeneration --> Disease occurs mainly in weak areas

Opinions on Nick Longrich's article

Why did modern humans replace the Neanderthals? The key might lie in our social structures (theconversation.com)

Opinions on Nick Longrich's article / Eam Taekyoung

I agree with Nick Longrich's argument above that differences in social structure may be the main reason why Neanderthals lost their competition with Homo sapiens. However, it is difficult to sympathize with the view that there is no significant difference between Neanderthals and modern humans (Homo sapiens) in physical terms.

1. Why did gorillas and chimpanzees survive and Neanderthals become extinct?

Neanderthals appear to have been in direct competition with modern humans. In particular, in the case of Neanderthals, there was a lot of geographic and cultural overlap with modern humans, which may have led to competition for resources and even violent conflict. It is highly likely that this competition contributed to the extinction of Neanderthals to some extent. However, gorillas and chimpanzees have a different ecological niche than modern humans, and have focused on adapting to their natural environment rather than directly competing with humans.

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2. What is the key reason why modern humans (Homo sapiens) won the struggle against Neanderthals?

I think it is worth noting the following regarding the differences between Neanderthals and Homo sapiens.

First, compared to modern humans, Neanderthals had characteristics such as shorter limbs, larger front teeth and roots, thicker metacarpals, and thicker necks. This is interpreted to mean that Neanderthals were physically more powerful than Homo sapiens. However, his running ability appears to have lagged behind. It appears that these physical differences affected the scope of activity and contributed to differences in the size of society.

Second, Neanderthals had a crooked and rough skeletal structure with a skull shape that was an intermediate evolutionary stage between Homo sapiens and gorillas. The shape of the Neanderthal skull appears to be between that of gorillas and Homo sapiens in the evolution of higher animals. It is less spherical than the skull of Homo sapiens. This means that the degree of transition to full erection is lower than that of Homo sapiens. The low degree of transition to full erection means that the energy consumed to support the moment caused by the head is relatively greater than that of Homo sapiens. This means that regardless of the type of activity, the basic energy consumption of Neanderthals was significantly greater than that of modern humans.

y = ax + b

b of Neanderthal > b of Homo sapiens

Neanderthals versus anatomically modern humans (youtube.com)

3. Summary

Just as it is difficult for products with low energy efficiency ratings to survive in the long term in modern society, the difference in the degree of uprightness of Neanderthals compared to modern humans caused a difference in energy consumption efficiency, and this difference caused a difference in the survivability of independent beings. Meanwhile, Neanderthals were in direct competition with humans in terms of geographic, cultural, and ecological status. In addition, physical characteristics related to running fitness caused differences in the size of society, and differences in size caused differences in social competitiveness.

Expedition Magazine | The Inhabitants of Ice Age Europe (penn.museum)

A hypothesis about why ancient primates lost their tails before walking on two legs

 

1. Interpretation of the function of the main foot bones of humans and chimpanzees

Among the foot bones, the bones to pay attention to are the calcaneus (heel bone) and the 1st metatarsal, and structurally, they have an arch shape that exists in the middle part of the lower foot (see Figures 1 and 2).

Figure 1

Figure 2

Meanwhile, the arch that exists on the lower middle part of the foot is mainly mentioned as a prominent feature of the modern human foot, and it is believed that if the arch collapses, pain or inflammation can be caused (see Figure 3).

Figure 3

I interpret the functions of the main foot bones of humans and chimpanzees as follows.

First, in humans, the calcaneus (heel bone) is the starting point of landing during running activities and plays a role in withstanding the repulsive force generated when a large body load is transmitted to the ground. However, in chimpanzees, the entire hind foot serves this function.

Second, the more the 1st metatarsal spreads laterally across the entire sole, the stronger its role in holding something becomes. Conversely, the smaller the spread or the thicker it is than the other four toes, the stronger its effective function for endurance running where inertial force changes are not severe.

Third, the arch, which is strongly developed in humans and exists in the lower middle of the foot when running, replaces the shock absorbing role of the spine of four-legged mammals.

Fourth, it can be interpreted that the functions of the hind feet, spine, and front feet of four-legged mammals are integrated into the human feet. When running, the landing function of the hind feet of four-legged mammals is handled by the calcaneus (heel bone) of modern humans, which exists at position 1 in Figure 4 below, and the shock absorption function of the spine is handled by the arch shape and position 2. , the function of the forefoot is now handled by the 1st metatarsal and sesamoid bone located in position 3.

Figure 4

Fifth, the direction of foot bone evolution among modern humans, including chimpanzees and several other species, was in the direction of strengthening the foot bone's function of grasping objects and running for long periods of time.

However, evolution in this direction appears to have occurred through natural selection and/or leaps (mutations) rather than the will of the species. And the results seem to have a direction in which optimal economics is further strengthened in relation to energy use.

2. In Apes, the arms perform the function of the tail in four-legged mammals

Earlier, I said that the functions of the hind feet, spine, and forelimbs of four-legged mammals can be interpreted as integrated into the human foot. So what role can the arms of apes, including humans, play when running? I am interpreting it as follows.

In four-legged mammals, the tail plays a role in controlling the inertial force of the body to prevent the body from derailing due to the inertial force when changing direction quickly and suddenly. The function of the tail is clearly demonstrated in a cheetah chasing its prey at full speed. In apes trying to stand upright, the tail would have been gradually degenerated or mutated because it was located lower on the body and had the effect of reducing the ability to properly control changes in the inertial force of the upper body. On the other hand, in apes that gave up high speed, the arms were able to fully replace the role of controlling the inertial force of the tail in four-legged mammals.

However, evolution in this direction appears to have occurred through natural selection and/or leaps (mutations) rather than the will of the species. And the results seem to have a direction in which optimal economics is further strengthened in relation to energy use.

A new hypothesis for why the brain capacity of human ancestors increased rapidly about 2 million years ago (Fully bipedal walking theory)

The dramatic growth of human ancestors' brains around 2 million years ago is a key topic in the study of human evolution, and several hypotheses have been proposed to explain this phenomenon. Here are the main theories and the one that is often considered the most likely:

Diet and Nutrition(Leslie Aiello and Peter Wheeler, Richard Wrangham): The inclusion of higher-quality foods, particularly after the advent of cooking and increased meat consumption, provided more energy and nutrients that supported brain growth. The "expensive tissue hypothesis" suggests that a diet rich in energy allowed other organs to be smaller, thus freeing up energy for a larger brain.

Social Brain Hypothesis(Robin Dunbar): This theory posits that complex social interactions and the development of larger social groups drove the need for a larger brain. This includes the complexities of communication, remembering individuals, forming alliances, and understanding social dynamics.

Ecological Challenges and Environmental Changes: Adapting to changing environments and ecological challenges may have spurred brain growth. This includes problem-solving, memory, spatial orientation, and understanding and manipulating the environment.

Tool Use and Technology(Kathy Schick and Nicholas Toth) : The development and use of tools may have driven brain expansion. The cognitive demands of making and using tools, which involves planning, dexterity, and understanding cause and effect, could have selected for greater intellectual capabilities.

Language Development(Steven Pinker, Noam Chomsky): The evolution of language capacities may have contributed to brain expansion, as complex language requires significant brain processing power.

Out of these, the most widely accepted and discussed is the combination of diet and social complexities. The dietary change hypothesis, especially the role of cooking and meat consumption, is often considered crucial because it provided the necessary energy and nutrients for supporting a larger brain. At the same time, the social brain hypothesis is also highly regarded, as the cognitive demands of living in complex social structures are thought to have significantly influenced brain development.

However, it's important to note that these hypotheses are not mutually exclusive and likely interact in complex ways. The dramatic enlargement of the brain in human evolution is probably the result of multiple, interrelated factors rather than a single cause.

I feel that the above hypotheses are not clear enough to completely remove the question. I believe that fully bipedalism was the main reason for the rapid increase in brain capacity between about 2 and 1 million years ago. 

Fully bipedal walking theory/Eam Taekyoung I believe that fully bipedalism was a major factor in the rapid increase in brain capacity in our human ancestors. Full bipedal walking means walking with the center of gravity of the head very close to the fulcrum where the feet contact the ground. This means walking in a position where the moment caused by the head is almost zero. Moment = weight of the head x distance the head protrudes horizontally from the point of support This fully bipedal walking minimizes the fixed expenditure of energy consumption due to posture. The resulting surplus energy increased brain activity, and increased brain activity led to the evolution of an increase in brain size. The use of fire that began about 1.4 million years ago appears to have acted as another factor in continuing this trend. It appears that complete bipedal walking itself could have been completed through the following process.

1. Extinction of the tail: The appearance of gibbons (living in the rainforest) whose long arms replaced the function of the tail.

2. Beginning of knuckle walking: The appearance of gorillas that knuckle-walk using their finger joints (living in the rainforest)

3. Beginning of bipedal walking: Approximately 21 million years ago, the appearance of Morotopithecus, which lived in the grasslands outside the rainforest by eating leaves with its bumpy molars(Morotopithecus was able to pick leaves by standing upright rather than leaning down, as leaves are everywhere on the branches)

4. Beginning of a mainly bipedal lifestyle: Approximately 3 to 2 million years ago, the appearance of Australopithecus living in open savannas/mixed savanna and rainforest/dry but water-rich river areas/bush forests, etc.

5. Beginning of deterioration of the offensive function of the jaw and teeth: Approximately 2.5 million years ago, the emergence of Homo habilis, which used tools

6. Beginning of fully bipedal life: The emergence of fully bipedal Homo erectus (about 1.9 million years ago) and the use of fire (about 1.4 million years ago) led to a rapid increase in brain capacity.

7. Evolving into a body optimized for running: Approximately 300,000 years ago, the emergence of modern humans (Homo sapiens) with bodies optimized for running.