The Brain: The Story of You

by David Eagleman

A mature pleasure-seeking system coupled with an immature orbitofrontal cortex means that teens are not only emotionally hypersensitive, but also less able to control their emotions than adults.

Imagine we’re sitting together in a coffee shop. As we’re chatting, you notice me lift my cup of coffee to take a sip. The act is so unremarkable that it normally bears no mention unless I spill some on my shirt. But let’s give credit where it’s due: getting the cup to my mouth is no easy feat. The field of robotics still struggles to make this sort of task run without a hitch. Why? Because this simple act is underpinned by trillions of electrical impulses meticulously coordinated by my brain. My visual system first scans the scene to pinpoint the cup in front of me, and my years of experience trigger memories of coffee in other situations. My frontal cortex deploys signals on a journey to my motor cortex, which precisely coordinates muscle contractions – throughout my torso, arm, forearm, and hand – so I can grasp the cup. As I touch the cup, my nerves carry back reams of information about the cup’s weight, its position in space,

its temperature, the slipperiness of the handle, and so on. As that information streams up the spinal cord and into the brain, compensating information streams back down, passing like fast-flowing traffic on a two-way road. This information emerges from a complex choreography between parts of my brain with names like basal ganglia, cerebellum, somatosensory cortex, and many more. In fractions of a second, adjustments are made to the force with which I’m lifting and the strength of my grip. Through intensive calculations and feedback, I adjust my muscles to keep the cup level as I smoothly move it on its long arc upward. I make micro-adjustments all along the way, and as it approaches my lips I tilt the cup just enough to extract some liquid without scalding myself.

The detached nature of distance warfare reduces internal conflict, making it easier to wage.

Without meaning to, people ape one another. Subtle movements of facial muscles can be measured with an electromyogram (EMG). This mirroring sheds light on a strange fact: couples who are married for a long time begin to resemble each other, and the longer they’ve been married, the stronger the effect. Research suggests this is not simply because they adopt the same clothes or hairstyles, but because they’ve been mirroring each other’s faces for so many years that their patterns of wrinkles start to look the same.