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Endnotes – Looking Back in Time
This is the background material that shapes the argument in Looking Back in Time.
The purpose of the brain is to control and coordinate. It connects to the body, monitors conditions and senses, determines what to do, and then sets the desired action in motion.
Observations: Brain Functionality
It’s a tough life being a wasp
Sitting in a garden, we may be pestered by a wasp. We might wave our arms, run away, ignore it, or ultimately kill it. Not every encounter ends in a sting, because decisions are being made by both us and the wasp.
A wasp’s physiology reflects a very early evolutionary architecture. Its small but efficient brain processes inputs from primitive counterparts of the senses:
- Vision (UV-sensitive compound eyes)
- Smell/taste (chemical receptors on antennae and mouthparts)
- Touch/vibration detection (antennae, body hairs)
- Motion detection (visual + mechanosensory)
This allows the wasp to interact with its environment quickly, almost entirely through rapid, automatic “System 1” style reactions. It has no “System 2” reasoning as humans do, yet this fast-response processing has been enough to ensure its survival.
Structure of the vertebrate brain
Evolution has produced many huge invertebrates, but they did not prevail. Vertebrates, on the other hand, developed increasingly complex brains.
Among the earliest vertebrates, brain structures like the hypothalamus (regulating metabolism, heartbeat, breathing) and the amygdala (tagging emotion and memory) were already present. These are often wrapped into the popular metaphor of the “lizard brain.” While not literally a separate “reptile-only brain,” the phrase points to the survival-focused regions that bias us toward instinctive, fast System 1 responses such as fight or flight.
Fossils suggest that Stegosaurus lived between 155 and 145 million years ago(1)(2). Its brain was small relative to its body, but its species endured for about 10 million years(2). By comparison, Homo sapiens have existed for only ~300,000 years — meaning the stegosaurus genus lasted over 30 times longer than we have so far. Longevity doesn’t imply intelligence, but it does highlight resilience. Stegosaurus also carried a defensive weapon — the thagomizer (its spiked tail) — which suggests it had evolved both the tools and the instinctive responses to use them.
In later vertebrates, new layers of brain tissue were added on top of this older survival system. Over time this culminated in the modern human brain, where the older regions remain active but are joined by the neocortex, which enables deliberate, abstract, System 2 thinking.
Consequences of the Observations
It’s a tough life being a wasp
For a wasp, quick reflexive decisions are everything. Its responses to threat can be boiled down almost to pseudocode:
If human.behaviour = arms.waving
Then Sting
End If
This works because the wasp operates with a limited but reliable set of fast responses. To humans, this often appears as aggression, especially when food or nests are threatened. In truth, wasps are generally not aggressive toward their own kind, but assertive toward potential threats. Their black-and-yellow “uniform” serves as a warning: I can sting, so don’t test me.
Structure of the vertebrate brain
Taking Stegosaurus as a reference point: it was not highly cognitive, but its endurance over millions of years shows the effectiveness of survival reflexes. The hypothalamus and amygdala — the core of the so-called “lizard brain” — supported functions such as:
- Scanning inputs from the body and environment
- Comparing them against thresholds for threat or imbalance
- Triggering scalable responses (fight, flight, freeze, physiological shifts)
This architecture defines System 1 survival reactions. The amygdala is not part of the autonomic system itself, but it strongly influences autonomic responses through connections with the hypothalamus and brainstem. Together, these regions provided fast, instinct-driven survival.
The modern human brain layers abstract reasoning and planning (System 2) on top of this architecture. But the older system still biases us toward snap judgments and reflexive emotions. Sometimes this is a strength (rapid danger response). Other times, it becomes a weakness — for example, reacting to news headlines or social triggers with fight-or-flight urgency, even when no real threat is present.
Action: Based on the Observations and Consequences
The wasp survives with fast, limited choices. The stegosaurus endured millions of years with reflexive responses and defensive hardware. Humans carry both these legacies forward:
- Older systems (hypothalamus, amygdala, brainstem) = System 1 survival engine.
- Newer systems (neocortex, prefrontal cortex) = System 2 deliberation and planning.
Recognizing this dual architecture helps explain both our strengths and our vulnerabilities: reflex saves us in an instant, but can also mislead us in a modern, abstract world.
📖 Series Roadmap
- Forward: A Little Background
- Introduction: Action, Reaction, and the Human Paradox (16.09.2025)
- Looking Back in Time: The Development of the Human Brain (23.09.2025)
- Abstract Senses: Enhancing the way we see the world outside (30.09.2025)
- Bias as a Concept & Climbing the Stairs: Pattern Recognition & Everyday Tasks (07.10.2025)
- Abstract Feelings and Abstract Senses (14.10.2025)
- Motivation (04.11.2025)
- The Social Knowledge Base (11.11.2025)
- Potential (18.11.2025)
- The Subliminal Way We Go Through Life (26.11.2025)
- Taking Responsibility (02.12.2025)
- Fishing for Complements (22.12.2025)
- Peter and Fermi (22.12.2025)
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Endnotes – Looking Back in Time
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