Key Takeaways
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Our brains evolved through five key breakthroughs that now influence how we age cognitively.
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Understanding cognitive evolution can guide healthy ageing strategies to support mental vitality.
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Lessons from brain evolution may help us shape both human longevity and ethical artificial intelligence.
Did you know your brain contains structural and functional features that have been shaped over 600 million years. From simple nerve nets in jellyfish to symbolic thought in humans, each evolutionary step added new cognitive capabilities — and many of those adaptations still influence how your brain ages today.
Max Bennett’s book, A Brief History of Intelligence, breaks this down into five major breakthroughs: life, neurons, learning, symbols, and abstraction. By looking back at how intelligence evolved, we can better understand how to maintain and even optimise our brain health for a longer, more vibrant life.
The First Breakthrough: Life and Longevity Began Together
Intelligence started with life itself. The earliest single-celled organisms could sense and respond to their environment — a primitive form of decision-making. These microbial ancestors laid the groundwork for everything that followed, including energy regulation, environmental awareness, and basic survival strategies.
Interestingly, these ancient cells also pioneered cellular longevity mechanisms, including autophagy — the body’s way of cleaning out damaged cells. Autophagy plays a critical role in preventing neurodegeneration (R), and it’s activated through lifestyle habits like fasting and exercise. The connection between ancient cellular function and modern brain health shows just how deeply evolution has programmed us for both survival and adaptation.
Neurons: The Building Blocks of a Thinking Brain
Roughly 600 million years ago, early multicellular organisms evolved neurons — specialised cells that could transmit electrical signals rapidly. This leap allowed animals to move, react to danger, and process information more efficiently.
Human brains now contain around 86 billion neurons (R), each forming up to 10,000 connections with others. Ageing impacts this network, but neuroplasticity — the brain’s ability to reorganise and form new connections — continues into later life, especially when stimulated by learning, physical activity, and meaningful social interaction.
Interestingly, older adults who engage in lifelong learning show increased neural connectivity in regions associated with memory and problem-solving (R). This supports the idea that your brain, much like your muscles, thrives on regular use.
The Power of Learning: How Memory and Experience Evolved
Learning changed the game for survival — and it still shapes brain health today. Once neurons arrived, evolution began favouring organisms that could learn from their environment. This third breakthrough introduced synaptic plasticity — the brain’s ability to strengthen or weaken neural pathways based on experience.
This mechanism underpins everything from remembering a loved one’s face to learning a new language. However, synaptic efficiency can decline with age due to factors like inflammation and oxidative stress (R).
But here’s the good news: exposure to novelty, aerobic exercise, and a Mediterranean-style diet rich in antioxidants can boost brain-derived neurotrophic factor (BDNF), a protein that supports learning and memory even in older adults (R). In other words, evolutionary learning mechanisms are still accessible — and optimisable — throughout your life.
Symbols: The Leap That Made Language and Culture Possible
The fourth breakthrough in intelligence was the development of symbols — the ability to assign meaning to sounds, shapes, or gestures. This is the basis of language, storytelling, and culture. These symbolic systems are uniquely human and central to both communication and memory.
Older brains often retain and even improve in semantic memory — your storehouse of vocabulary, facts, and cultural knowledge. This means your ability to understand and work with meaning can remain strong, even as other types of memory change.
In fact, research shows that verbal intelligence — including vocabulary and language comprehension — tends to peak or remain stable well into the 60s and 70s (R). That’s a compelling reason to engage with literature, discussion groups, or even writing in later life.
Abstract Thinking and the Future of Human Intelligence
The fifth evolutionary milestone Bennett explores is abstraction — the ability to think about ideas that aren’t directly tied to the physical world. This includes mathematics, philosophy, ethics, and even self-reflection.
Abstract thinking is one of the most powerful cognitive tools we have. It enables future planning, empathy, and the ability to see patterns and connections across time and space. While some processing speed may decline with age, wisdom-related reasoning — such as emotional regulation and moral insight — often improves (R).
This type of intelligence is harder to replicate in machines and may become one of the most valuable forms of human cognition in the age of artificial intelligence.
How Evolution Helps Us Age Smarter
Your cognitive blueprint is ancient, but its maintenance is very modern. By tracing the history of our intelligence, we gain a deeper appreciation for how resilient — and adaptive — the human brain truly is. Evolution didn’t stop at creating intelligence; it also embedded ways to protect and enhance it across the lifespan.
Activities that support mitochondrial health, reduce inflammation, and stimulate neuroplasticity are not just helpful — they’re biologically aligned with your brain’s original evolutionary design.
This includes:
- Regular movement (especially aerobic and weight-bearing exercise)
- A nutrient-rich diet (with polyphenols, omega-3s, and magnesium)
- Lifelong learning and curiosity
- Restorative sleep and circadian rhythm alignment
Together, these lifestyle habits echo the fundamental principles that helped our brains evolve — and they can help yours thrive well into later life.
The Link Between Natural Intelligence and Artificial Intelligence
Your brain may hold the clues to building ethical, human-centred AI. Bennett also draws intriguing parallels between the evolution of biological intelligence and the rapid development of artificial intelligence. Understanding how human cognition evolved — including our emotional and moral frameworks — is essential if we’re to guide AI development in ethical directions.
Ageing Brains Are Evolved for Wisdom
Evolution hasn’t left you behind — it has prepared you for your most insightful years. By embracing the legacy of your brain’s long journey, you can make lifestyle choices that support not just longevity, but thriving cognition.
Curious about how your everyday choices affect your cognitive health? Read our blog: Your Comprehensive Guide to Brain Health.
