The Brain: The Story of You

by David Eagleman

On the face of it, that seems like a great advantage for other species – but in fact it signifies a limitation. Baby animals develop quickly because their brains are wiring up according to a largely preprogrammed routine. But that preparedness trades off with flexibility.

the language that you’re exposed to in infancy (say, English versus Japanese) refines your ability to hear the particular sounds of your language, and worsens your capacity to hear the sounds of other languages. That is, a baby born in Japan and a baby born in America can hear and respond to all the sounds in both languages. Through time, the baby raised in Japan will lose the ability to distinguish between, say, the sounds of R and L, two sounds that aren’t separated in Japanese.

who we are as a teenager is not simply the result of a choice or an attitude; it is the product of a period of intense and inevitable neural change.

Our brains and bodies change so much during our life that – like a clock’s hour hand – it’s difficult to detect the changes. Every four months your red blood cells are entirely replaced, for instance, and your skin cells are replaced every few weeks. Within about seven years every atom in your body will be replaced by other atoms. Physically, you are constantly a new you. Fortunately, there may be one constant that links all these different versions of your self together: memory. Perhaps memory can serve as the thread that makes you who you are. It sits at the core of your identity, providing a single, continuous sense of self.

The neurons that are active at the same time will establish stronger connections between them: cells that fire together, wire together. The resulting network is the unique signature of the event, and it represents your memory of the birthday dinner.

You don’t perceive objects as they are. You perceive them as you are.

We’ve just seen that the brain processes sounds more quickly than sights. And yet take a careful look at what happens when you clap your hands in front of you. Try it. Everything seems synchronized. How can that be, given that sound is processed more quickly? What it means is that your perception of reality is the end result of fancy editing tricks: the brain hides the difference in arrival times. How? What it serves up as reality is actually a delayed version. Your brain collects up all the information from the senses before it decides upon a story of what happens.

In other words, when things are life-threateningly scary, it’s a good time to take notes.

the pain matrix is crucial to how we connect with others. If you watch somebody else get stabbed, most of your pain matrix becomes activated. Not those areas that tell you you’ve actually been touched, but instead those parts involved in the emotional experience of pain. In other words, watching someone else in pain and being in pain use the same neural machinery. This is the basis of empathy.

Genocide is only possible when dehumanization happens on a massive scale, and the perfect tool for this job is propaganda: it keys right into the neural networks that understand other people, and dials down the degree to which we empathize with them.

Our species owes its runaway success to the special properties of the three pounds of matter stored inside our skulls.