Read How We Decide for Free Online Page A

stood up," he says. "The actor didn't even know his lines because he had gotten the script late. I just saw him say a few words, and then I knew. He was unbelievably great. I couldn't explain why, but for me he completely stood out. What they say is true: you just get a feeling."
    The mental process Stein is describing depends on his emotional brain. Those twinges of feeling that help him select the right camera and find the best actor are a distillation of all those details that he doesn't consciously perceive. "The conscious brain may get all the attention," says Joseph LeDoux, a neuroscientist at NYU. "But consciousness is a small part of what the brain does, and it's a slave to everything that works beneath it." According to LeDoux, much of what we "think" is really driven by our emotions. In this sense, every feeling is really a summary of data, a visceral response to all of the information that can't be accessed directly. While Stein's conscious brain was blocking the script, his unconscious supercomputer was processing all sorts of data. It then translated that data into vivid emotional signals that were detected by the OFC, allowing Stein to act upon these subliminal calculations. If Stein were missing his feelings—if he were like one of Damasio's patients—then he would be forced to carefully analyze every alternative, and that would take forever. His episodes would be constantly delayed and he would cast the wrong actors. Stein's insight is that his feelings are often an accurate shortcut, a concise expression of his decades' worth of experience. They already know how to shoot the scene.

    WHY ARE OUR emotions so essential? How did they get so good at finding the open man and directing soap operas? The answer is rooted in evolution. It takes a long time to design a brain. The first clumps of networked neurons appeared more than five hundred million years ago. This was the first nervous system, although at that point it was really just a set of automatic reflexes. Over time, however, primitive brains grew increasingly complex. They expanded from a few thousand neurons in earthworms to a hundred billion connected cells in Old World primates. When
Homo sapiens
first appeared, about two hundred thousand years ago, the planet was already full of creatures with highly specialized brains. There were fish that could migrate across the ocean using magnetic fields, and birds that navigated by starlight, and insects that could smell food from a mile away. These cognitive feats were all byproducts of instincts that had been engineered by natural selection to perform specific tasks. What these animals couldn't do, however, was reflect on their own decisions. They couldn't plan out their days or use language to express their inner states. They weren't able to analyze complex phenomena or invent new tools. What couldn't be done automatically couldn't be done at all. The charioteer had yet to appear.
    The evolution of the human brain changed everything. For the first time, there was an animal that could think about how it thought. We humans could contemplate our emotions and use words to dissect the world, parsing reality into neat chains of causation. We could accumulate knowledge and logically analyze problems. We could tell elaborate lies and make plans for the future. Sometimes, we could even follow our plans.
    These new talents were incredibly useful. But they were also incredibly new. As a result, the parts of the human brain that make them possible—the ones that the driver of the chariot controls—suffer from the same problem that afflicts any new technology: they have lots of design flaws and software bugs. (The human brain is like a computer operating system that was rushed to market.) This is why a cheap calculator can do arithmetic better than a professional mathematician, why a mainframe computer can beat a grand master at chess, and why we so often confuse causation and correlation. When it comes to