Every brain has a different internal life. Each its own unique story.
That story is the story of you—who you are and who you will become, says neuroscientist David Eagleman. In his new book The Brain, he looks at this universe inside your head from the beginning to the end, and discusses how this small organ generates "you" and the reality around you.
The Brain is a companion book to a PBS series of the same name, which premieres tonight. Opening with fundamental questions, such as "what is reality?" or "who am I?" Eagleman takes viewers and readers on a fascinating introductory journey focused on the brain. But that shouldn't be a turn-off for the initiated; the ride contains enough depth to keep neuroscientists as engaged.
The brain itself takes a journey throughout one's life, enduring a constant shape shifting that occurs as we grow and as life experiences build up. We are "born unfinished," Eagleman says. Infants have many unconnected neurons that go on to form two million connections every second as the newborn brain grows, doubling its initial size in just the first few months. Infants also have many wrongly connected neurons in dire need of pruning. "You become who you are not because of what grows in your brain, but because of what is removed," Eagleman writes.
Although the radical shape shifting eventually slows down, the brain remains plastic, changes with every new experience, shapes who we become, and sometimes even reflects who we are. This concept is manifested most famously in the case of London cabbies whose memorization of streets and paths is reflected in their enlarged hippocampus, the brain structure crucial for memory formation. Many other professions and skills, too, are found to leave their particular imprint on our brains.
But biology still has a say— in the most dramatic cases, brain damage or a tumor could fundamentally change a person. Just like what's believed to have happened to Charles Whitman, who, to the surprise of anyone who knew him, turned into a violent mass murderer in 1966. He later was found to have a tumor compressing his amygdala, a brain structure involved in emotional processing.
The brain not only determines who you are, but also what the world around you looks like. Our internal perception of the outside world is hardly a precisely mirrored image. Instead, what we perceive is composed of a sampling of the world, with the brain filling in the gaps using built-in mechanisms. How closely our version of reality matches the outside world is at the mercy of the brain, which itself has no direct access to the outside. "Sealed within the dark, silent chamber of your skull, your brain has never directly experienced the external world, and it never will," Eagleman writes. So what is reality? It's whatever simulation your brain makes. Examples of visual illusions and Eagleman's own space-bending and time-warping experiments bring this point home.
But as black-boxed and isolated our brains are, they can't be left alone. One chapter (and episode) titled "Why Do I Need You?" discusses the social brain and how we interact with others. To understand how important social interaction is for the brain to function normally, one just needs to look at extreme cases of isolation, such as solitary confinement for extended periods. Eagleman also discusses the field of social neuroscience, examining everything from how we read others' emotional states to how we treat members of an outside group and how such a highly social species can also commit horrendous anti-social acts such as genocide.
Our brains are fascinating just the way they are, but that doesn't mean technology won't provide an upgrade. Eagleman discusses his own vision of the future, one in which the internet is streamed directly into our bodies and we enjoy our new additional senses of the weather and stock market trends. Although this sounds like science fiction, Eagleman argues it's based on the reality of how the brain works. If you feed it data, it uses its special talent for extracting patterns, and you end up with a whole new sensory modality. And our bodies, too, could be augmented—the idea is a natural extrapolation from mind-controlled robotic arms and other brain-computer technology that already exists.
To join Eagleman in exploring the wonders and mysteries of the brain, get The Brain: The Story of You (Pantheon Books), available on Amazon and Barnes & Noble or watch the series debuting tonight Wednesday Oct. 14 at 10 p.m. ET (9 p.m. Central) on PBS.