The Brain: The Story of You by David Eagleman, a professor of neuroscience and researcher, is a fascinating exploration of the human brain, written in an accessible and engaging style. Like a good storyteller, Eagleman weaves together latest advances in brain research, psychological experiments, real life examples and philosophical anecdotes, to take you to the fantastical world of the little universe packed inside our skulls, and in the process demystifies its workings by laying bare the neural mechanism into its constituent parts and steps. Divided into six thematic chapters titled after some of the fundamental questions that have intrigued and continue to provoke human thought throughout history, the author grounds some of the basic sociological processes in biological mechanisms. ‘The Brain: The Story of You’, David Eagleman, Canongate, 2016.This work would certainly make the likes of August Comte and Herbert Spencer proud, as it merges biology with sociology, offering a nuanced understanding of human behaviour and society. However, it avoids falling into the trap of biological determinism, acknowledging instead the complex interplay between our continuously evolving neural wiring, in the context of dynamic social interactions that shapes our experience.Every human in born with approximately 86 billion neurons in their brain. At birth, these neurons are unconnected and disparate. The human brain at this stage is tabula rasa; blank slate upon which scribbling begins. As the infant enters the human society, connections, termed as synapses began to form between these neurons, and by the age of two, there are approximately 100 trillion synapses, the peak, after which neural pruning begins. The second stage of synapses formation begins just before the onset of puberty and continues throughout the teenage years with simultaneous pruning. By the age of 25, neural changes in the brain gets stabilised with changes occurring at glacial pace. By adulthood, a human brain is left with only 50% of the synapses that were formed by the age of two. But why do synapses form and why are they pruned? Synapses are formed to facilitate communication between neuron, and are formed in the process of leaning and experiencing new things generating a neural circuit. In early childhood, the brain creates a massive number of synapses – far more than it actually needs. The brain does this to maximise learning potential, creating connections for every possible experience a child might encounter. But not all those connections are useful long-term. Synapses that are used frequently get strengthened, while those that are rarely or never used are pruned away. For example, a child exposed to multiple languages will retain more synapses related to learning a particular language, while unused language pathways might fade away. This shows that in early stages human child is exposed with the possibility of learning everything and anything, only constrained by the cultural environment. As Eagleman says: “You become who you are not because of what grows in your brain, but because of what is removed.” This dynamic aspect of neural circuitry is termed ‘neural plasticity’ as synapses keeps on forming and pruning throughout life; the biological counterpart of life long socialisation. The first chapter titled ‘Who Am I?’ discusses the biological counterpart of the process of socialisation, i.e. how our experiences that shape us gets reflected in the structure of the brain. “Everything you’ve experienced has altered the physical structure of the brain…Your family of origin, your culture, your friends, your work, every movie you’ve watched, every conversation you’ve had- these have left their footprints in your nervous system”.The human brain, as Eagleman points out is highly malleable, which he terms ‘live wiring’, instead of animal brains which are ‘hard wired’ since birth. The malleability or neuroplasticity of human brain enables humans to learn and adjust based on our surroundings.What is Reality? The second chapter titled ‘What is Reality’ explores how the brain constructs our perception of reality. Eagleman points out to the fact that what we call ‘reality’ is not an objective experience but a subjective creation of the brain, influenced by sensory inputs and internal models based on our experiences. As he says, “outside our brain, there is just energy and matter”; there are no colours, sound, odour or taste in the real world. Our sensory organs convert external stimuli into electro-chemical signals, which are then interpreted by the brain. Moreover, this perception is just a small slice of what lies out there because of the limitations imposed by our biology. Our eye is capable of seeing only a tiny portion of electromagnetic spectrum, i.e. the visible spectrum; our ears are capable of hearing the tiny ‘audio frequency’ generated by change in pressure in air around us. Imagine if we are able to see and hear entire spectrum; the world would appear to us as a chaos of colours and sound! In the chapter Eagleman also draws our attention to some of the fascinating aspects of how our brain works. For e.g. he explores brain’s remarkable ability to construct an internal model of the world. This model isn’t a direct reflection of reality but a dynamic representation or approximation of the world built from sensory inputs and past experiences. Brain processes raw data from the senses, integrating them into a coherent narrative that helps us navigate life.How Do I Decide?The third chapter titled ‘Who is in Control?’, touches upon one of the most debated topics in social and medical sciences, i.e. the consciousness and the unconscious. Eagleman delves into the tension between conscious decision-making and the powerful influence of unconscious processes. He explains that much of what we do is driven by brain activity outside our awareness. As he writes: “the reach of the unconscious mind extends beyond control of our bodies”. While we like to think we make deliberate choices, studies reveal that decisions often originate in unconscious neural circuits before we become aware of them. Eagleman explores the brain’s division of labour: conscious thought handles complex, novel problems, while unconscious processes manage routine tasks, as skills we learn keep sinking below the reach of concisions awareness, which makes us run on ‘autopilot mode’ after we have mastered the skill. For example, when learning to drive, we consciously focus on every action, but over time, these actions become automatic. This efficiency allows the brain to reserve conscious attention for unexpected situations. How do we make decisions? How do we decide what to eat? How much to save and what to do?How Do I Decide?In the fourth chapter titled ‘How Do I Decide’, Eagleman discusses the biological process through which we make our everyday decisions. Eagleman underlines the important role of subconscious in making our decision by emphasising that most of the time we are not aware of the decisions made on your behalf. Physiological states, such as hunger or fatigue, can substantially impact our decisions. For instance, Eagleman quotes studies that have shown that judges’ parole rulings vary based on the time of day, often being more lenient after meal breaks, highlighting how bodily states can sway judicial decisions. Rather than being controlled by a single, unified voice, our brains function more like a bustling parliament, i.e. “neural parliament”, with multiple competing factions – each representing different drives, emotions, and priorities. These factions constantly “debate” to influence the final outcome of a decision. Following this the chapter also delves into the brain’s inherent bias toward immediate rewards over long-term benefits, which Eagleman terms “the power of now”. A preference for immediate gratification explains why people make decisions that feel good in the moment but have lousy consequences in future. To counteract this tendency, Eagleman discusses strategies such as “Ulysses contract,” (named after legendary hero of the Trojan War) – something in which we engage quite often – where engage in a deal with our present and future self to mitigate impulsive decisions. For example, when we promise ourselves a reward after having successfully completed a task, we are engaging in Ulysses contract.Do I Need You?In the penultimate chapter titled ‘Do I Need You’, Eagleman explores the neuroscience behind human connection, emphasising how our brains are inherently social. Our social skills, as Eagleman says are deeply rooted in our neural circuitry. In this chapter Eagleman explains that our survival has always depended on group dynamics, shaping our neural architecture to prioritise relationships. Eagleman introduces the concept of mirror neurons, which fire both when we perform an action and when we observe someone else doing the same. This mechanism underlies our capacity for empathy – allowing us to feel and understand others’ emotions. He also discusses the hormone oxytocin, often called the “bonding hormone,” which strengthens trust and intimacy, reinforcing social ties. The chapter highlights how social rejection triggers the same brain regions as physical pain, demonstrating that feeling excluded can be as distressing as a physical injury. Ultimately, Eagleman argues that human identity isn’t formed in isolation; the self doesn’t exist in a vacuum, but emerges through interactions with others. Our relationships shape our thoughts, behaviors, and even neural structures. In this way, we are not purely individuals but interconnected beings, constantly influencing – and being influenced by – the people around us with a drive to from in-groups and out-groups. Who Will We Be?The final chapter titled ‘Who Will We Be’, explores the future of the human brain and how technology is reshaping our evolution by touching upon some the themes from science fiction movies and literature. Eagleman reflects on how our brains are constantly adapting to the world around us, and as technology advances, this adaptability opens new possibilities for human potential. Eagleman discusses innovations like brain-computer interfaces (BCI’s), which allow direct communication between the brain and machines. These technologies could help people with disabilities regain lost functions or even enable new sensory experiences beyond what evolution has given us. The chapter also discusses the possibility of storing our brain in cloud leading to digital immortality. In light of these developments resulting from the merger of technology and biology, the chapter also examines the ethical and societal implications of these advances like what it means to be human. If we can enhance cognition, memory, or emotions with neural implants, where do we draw the line between natural and artificial? Ultimately, Eagleman suggests that humanity is on the cusp of defining its next chapter, where brain plasticity and technological progress could push the boundaries of human existence in ways we’re only beginning to imagine.Lastly, spread over 220 pages, The Brain: The Story of You can be described as part of the emerging interdisciplinary field of neurosociology, or social neuroscience bridging neuroscience and social science to explore the intricate connections between the brain, behaviour, and society. The book offers you insights that will leave you thinking long after you’ve turned the last page, and might motivate you to read further about this emerging field of research. Harshvardhan Tripathy is Assistant Professor, Sociology, University School of Liberal Arts, Guru Gobind Singh Indraprastha University.
