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IN 2021, ECONOMIST TIMOTHY WARING AND biologist Zachary Wood of the University of Maine sent shockwaves through the world of biological sciences with their Royal Society publication suggesting that humanity was undergoing a shift in the evolution of individuality. Rather than the fitness of an individual’s genes driving a competitive process of selection, they proposed that environmental context was now propelling human development from one generation to the next, at a remarkable pace. In the complex dance of genes and environment referred to by scientists as ‘gene– culture coevolution’, orthodox opinion had long held that genes were the leader and environment the follower. Having reviewed the latest science behind this vast and crucial biological debate, Waring and Wood concluded: ‘If genes hold culture on a leash, culture is [now] dragging them straight off the trail.’1 They proposed that for the first time in our species’ long, slow development, culture (comprising everything that shapes our lived experience, from caregiving, social relations and learning, to diet and exposure to pollution) has a more deterministic influence than genes on our behaviours and outcomes, and that this effect is accelerating. If you’d told me twenty years ago that humanity was heading for a rapid evolutionary shift, driven not by genes but by environmental factors, I’d have been intrigued but sceptical. My days (and many nights) were spent down in the basement of the Anatomy Building at the University of Cambridge, patiently sitting by a microscope and staring at slices of brain tissue. I was completing my PhD research on connectivity between brain cells, looking at how this neural architecture supports learning and memory, in our perception of the world around us, and how it sometimes goes wrong in cases of psychosis. This was at the height of the genetics-driven revolution in neuroscience, when there was huge excitement about the world-changing potential of the decoding of the human genome, which had been ongoing throughout my undergraduate studies. There was also a scientific consensus about the primacy of genes in determining how our individual biology is formed, which was a cornerstone of the case I made in my first book,2 The Science of Fate. At that time, the influence of intertwining genetic and environmental factors on our health, personality and intelligence was increasingly well understood, but to my mind it had been translated into a slightly misleading message: that neuroplasticity meant we could change our outcomes and characteristics at will. I wanted to explain why that wasn’t the case. Since then, the science of epigenetics has galloped ahead, establishing that environmental factors can alter genes over the course of an individual’s lifetime, so that within one generation outcomes may look very different. As well as the glacial timescale of adaptation I was familiar with through my own research, scientists were observing a real-time shift in how the blueprints for life were changing in response to our supercharged environment. Studies in genetics continue to enrich the way we understand ourselves and the world, as well as being a vital resource for researchers of every discipline, from biology to sociology. Pioneers in tech-driven biomedical research are teaching AI the language of the genome so it can identify molecules to be developed into treatments for rare diseases, as we will see later in this book. In fact, such AI is able to trawl through the vast data sets of our genetic, protein and microbial make-up. We now have access to staggering amounts of detailed information that, with AI’s help, is allowing us to investigate our biology at the most granular level. What this reveals is the extent to which all systems are interconnected. Rather than providing reductive answers to complex questions about individuality and our future prospects, this work is adding layers of sophistication to our knowledge of what makes us human and drives our flourishing. Scientific understanding evolves as we do and we’re currently living through an era-reshaping shift in how we think about the biology of individuality, identity and intelligence. Waring and Wood are far from alone in believing that human beings are undergoing a major evolutionary transition. We seem to be moving away from individual biology shaped primarily by our inherited genes towards a socially integrated mega-group fashioned by the hyper-connected environment we have created with the help of technology. Is humanity evolving to become more like a colony of ants or hive of bees? Or perhaps more like a computer-aided ‘hive mind’? This suggestion can feel outlandish, unnerving or exciting, depending on your attitude towards biology and technology, but it is not a fringe viewpoint. The evidence is clear that we have built a digital world so pervasive and powerful in its effects that it constitutes a whole new environment. We can now communicate with each other in unprecedented ways, sharing our views, ideas and perspectives at the simple click of a button. And given that we know that environment and genes are locked together in a perpetual dance, it is entirely predictable that our biology will adapt. As Waring and Wood put it: ‘We speculate that, in the long term3 , culture will continue to grow in influence over human evolution, until genes become secondary structures that hold human biological design blueprints but are ultimately governed by culture.’ What is surprising is the speed and scale of that adaptation. I believe we all need to grasp that our success in this hyper-connected world will be determined not by our understanding of the tech itself but by our ability to behave intelligently in our continually updating environment. The potential rewards are enormous. This message about evolutionary shifts and leaps in intelligence might feel like a lot to take in at the very beginning of the book, but my intention is not to alarm or overwhelm. Quite the opposite. My suggestion is that we already possess all the cognitive skills we need to flourish in the decades to come. Human beings are exquisitely smart, creative and adaptable. You are more than capable of flexing with the times and deploying your evolved skill set and your personal learning to help you, your family, friends, colleagues and community to thrive. I’ve written this book in order to show you how you can do that, sharing insights from the world’s most cuttingedge cognitive science to illuminate how your amazing brain works, its strengths and its blind spots, so you can feel confident in your ability to navigate this new era of human intelligence. It might help you to know that human beings have been here before. Between approximately 5,000 and 3,000 years ago, our species went through an evolutionary shift towards collective intelligence brought about by a significant and relatively sudden technology-driven change in our environment. We had established agriculture and created sprawling civilizations, helped by advancements in machinery and technology, and we developed writing. We entered a period characterized by exploration and cultural exchange. With these changes, our capacity to store information outside our individual brains and to cooperate in larger groups over longer periods was ramping up. Our brains shrank in physical size4 even as our neural and social networks became more complex. It might seem counterintuitive that our brain size was diminishing as these changes occurred, but scientists have suggested that when the total cognitive load is divided and delegated among different members of a group with various roles, each individual can be more efficient. A trend towards efficiency of networks takes over and brain size falls. Intelligence goes collective, which in turn drives further biological and cultural changes, as it did with our ancestors all those years ago. Times may change for the human brain but plenty of crucial things about it haven’t altered and remain a constant source of wonder for me. I’m still in awe of the extraordinary processing that takes place in this 1.4kg of soft flesh encased in each of our skulls in which some 86 billion nerve cells are deployed, using chemical and electronic messages to process signals from the outside world and instruct us on how to interact with it. Each nerve cell is linked to up to 10,000 others, forming a circuit board of 86 trillion connections. Electrical signals zip around this infinitely sophisticated network, or connectome, at speeds of up to 120 miles per hour, allowing us to build a model of reality via perception, to form memories, learn from experience, generate emotions, to sense, move, speak and, in a word, live. I continue to be amazed by the brain and the mind it gives rise to and excited at the thought that we may all be standing on the cusp of a leap forward in human intelligence. A cursory glance at a newsfeed is enough to show us that we’re also facing serious challenges. To the ancient foes of war, famine and plague we can now add the climate and ecological emergency, which is fuelling all three. The technologies that are reshaping our environment at warp speed pose risks as well as bringing benefits. A hyper-connected world in which information and ideas flow freely is a thrilling, overwhelming, vulnerable place to live. AI might be the most powerful tool we could possibly have invented for dealing with the challenges that face us, precisely the gamechanging intervention we need; but it also poses alarming risks to our integrity and possibly even to our very survival. We need to work together with all hands on deck if we’re to stand a chance of tackling these challenges; or rather, we need all brains on deck. Collaboration and innovation have never been more essential, but in a polarized and individualistic world where we simultaneously know too much and too little, revere a handful of individuals slavishly and overlook millions of others, it can be hard to feel optimistic about our capacity for coming up with a smart response. In the following pages, I hope to convince you of the reasons to be positive about humanity’s potential to thrive in this new era. We already know we’re capable of enormous courage, creativity, resilience, resolve, compassion and kindness. These great virtues have their roots in evolved behaviours. They’re part of your inheritance and our species’ repertoire; we just need to decide to unleash them. During the writing of this book, I’ve thought hard about what might equip us to future-proof our brain and thrive in the coming decades. I’ve looked at many of the skills that make up our staggeringly impressive cognitive toolkit, from empathy and collaboration, creativity and problemsolving, to thinking slowly and over the long term as well as fast and in the moment. I’ve considered curiosity, resilience, focus, coping with uncertainty, learning, staying flexible and growing wise. I’ve spoken with many brilliant scientists whose work is expanding what we know about how our brain functions and our mind develops. I’ve chatted with people about their experiences of how their particular brain shapes their lived experience, from individuals with hyperphantasia (a vastly rich visual imagination) and ADHD to those with schizophrenia and bipolar disorder. All have been supremely generous and open with me, and I am profoundly grateful to them. A number of things began to crystallize for me, as I applied myself to thinking about how to live a rewarding, happy and successful life in the twenty-first century. Once I had allowed my mind to wander (good for sparking creative insights) before focusing on a particular point, when I’d paused to question my assumptions and sought another opinion to counter my cognitive bias, once I’d rested and thought hard again, I was struck by the recurrence of two themes that run throughout everything I’ve learned: the importance of physical movement and diversity of thought in fostering human intelligence, on both an individual and a collective level. These concepts crop up in relation to virtually every cognitive skill, task and intervention I’ve investigated.