Part I: What Is Emotion? 1 Thought Versus Feeling On the morning of Halloween 2014, a strange aircraft ascended high into the skies above the barren Mojave Desert. The custom-­built carbon-­fiber plane was essentially twin cargo jets flying side by side, joined at the wing. Suspended from that monstrous carrier vessel was a smaller plane dubbed the Enterprise--­an homage to Star Trek. The aim was for the cargo jet to carry the Enterprise to an altitude of fifty thousand feet, from where it would be dropped, briefly fire its engines, and then glide to a landing. The planes belonged to Virgin Galactic, the company created by Richard Branson to carry "space tourists" into suborbital flight. By 2014, more than seven hundred spaceship tickets had been sold, at $200,000 to $250,000 each. This was the thirty-­fifth such test flight but only the fourth in which the Enterprise was meant to fire up its rocket, which had just been redesigned to make it more powerful. The ascent went well.

The pilot David Mackay launched the Enterprise from the underside of his carrier plane at the appointed moment. Then his eyes panned across the sky, searching for the plume of the Enterprise''s rocket engine. He couldn''t spot it. "I remember looking down and thinking, ''Well that''s strange,'' " recalled Mackay, experienced enough to be wary of anything unexpected.1 But all was well. Out of his line of sight, the spaceship had indeed fired its rocket and in about ten seconds accelerated through the sound barrier. The mission was unfolding without incident. The Enterprise was captained by a test pilot named Peter Siebold, with almost thirty years of flying experience.

His ­co-­pilot, Michael Alsbury, had previously worked with eight different experimental aircraft. In some ways, the two men were quite different: while Siebold could strike ­co-­workers as aloof, Alsbury was always friendly and known for his sense of humor. But strapped into their seats atop the rocket, they functioned as a unit, each of their lives dependent on the actions of the other. Just before reaching the speed of sound, Alsbury unlocked the ship''s air-­braking device. The brake was crucial for controlling the spaceship''s orientation and speed while dropping back to earth, but it wouldn''t be needed for another fourteen seconds, and Alsbury had unlocked it before he should have. The National Transportation Safety Board would later criticize the Scaled Composites unit of Northrop Grumman, which designed the vehicle for Virgin, because it did not guard against such human slipups by providing a fail-­safe system to prevent premature unlocking. Unlike Virgin Galactic, government-­sponsored space initiatives call for "two-­failure tolerance." That means putting in place safeguards to protect against two separate and unrelated simultaneous problems--­two human errors, two mechanical errors, or one of each.

The Virgin team was confident that its extraordinarily well-­trained test pilots wouldn''t make such mistakes, and eliminating safeguards had certain advantages. "We don''t have all the constraints a government organization like NASA would," one team member told me. "So we can get things done a lot faster."2 But on that Halloween morning, the lock disengagement was no harmless mistake. With the lock off prematurely, the force of the atmosphere caused the brake to deploy early, even though Alsbury never threw the second switch to deploy it. As the brake swung into position, the still-­firing rocket placed tremendous stress on the plane''s fuselage. Four seconds later, traveling at 920 miles per hour, the ship ripped apart. From the ground, it looked like a massive explosion.

Siebold, still attached to his ejection seat, was thrown from the plane. Traveling faster than sound, he was in an atmosphere where the temperature of the air around him was minus seventy degrees Fahrenheit, and there was just one-­tenth the oxygen present at sea level. Still, he somehow managed to unbuckle himself, after which his parachute automatically opened. Upon rescue, he had no memory of the experience. Alsbury wasn''t so lucky. He died instantly when the plane broke apart. Emotions and Thought The long string of well-­rehearsed procedures called for when a pilot tests a new plane are normally executed so smoothly that it''s easy to think of them as rote and mechanical. But that view is profoundly misguided.

When the Enterprise was dropped from its mother ship and started to fire its ferocious rocket engine--­as planned--­the physical circumstance of its pilots was suddenly disrupted. It''s hard to imagine what that felt like, but a rocket is really a controlled exploding bomb, and a controlled explosion is still an explosion. It''s a terribly violent event, and the Enterprise was relatively flimsy--­a mere twenty thousand pounds, loaded, as compared with the space shuttle''s four million. And so the ride is much different. If flying in the space shuttle is like racing down the highway in a Cadillac, piloting the Enterprise was like driving 150 miles per hour in a go-­kart. The souped-­up rocket''s firing subjected the Enterprise pilots to a colossal roar, savage shaking and vibration, and fierce stresses of acceleration. Why did Alsbury throw the switch when he did? The flight was proceeding as planned, so it''s not likely he was panicking. We can''t know what his reasoning was, nor perhaps did he.

But in the anxious state that comes from a highly stressful physical environment, we process data in a manner that is hard to predict from practice runs in flight simulators. This was more or less the conclusion of the National Transportation Safety Board about the events on the Enterprise. Speculating that Alsbury, lacking recent flight experience, might have been unusually stressed, the NTSB posited that he committed the misjudgment due to the anxiety caused by time pressure and the ship''s strong vibration and forces of acceleration, which he hadn''t experienced since his last test flight eighteen months earlier. The story of the Enterprise illustrates how anxiety can lead to a bad decision, as it surely sometimes does. In our ancestral environment, there were many more life-­threatening dangers than we typically face in civilized life, and so our fear and anxiety reactions, in particular, may at times seem overblown. Such cases, as exemplified by the Enterprise saga, are what, over the centuries, gave emotion a bad name. But stories of emotions causing problems are often sensational, as this one was, while tales of emotions operating as they should tend to be mundane. It is the malfunctions that stand out in the telling, while a properly functioning system can easily go unheralded.

There were, for example, thirty-­four successful prior test flights of the Enterprise. In each of those, both the plane and its pilots operated as planned, controlled by a miraculous marriage of modern technology and the smooth interplay of the rational and emotional human brain, and none of them made the news. A case that hit closer to home for me concerned a friend who lost his job, and therefore his health insurance. Knowing the cost of decent medical care, he became anxious about his health. What if he got sick? He could go broke. That anxiety affected his ­thinking--­if he had a sore throat, he didn''t ignore it or dismiss it as sniffles as he''d have previously done. Instead, he''d fear the worst: Was it throat cancer? As it turned out, his anxiety over his health saved his life. For one of the things he had never paid attention to, but now began to worry about, was a mole on his back.

For the first time in his life, he went to a dermatologist and had it checked out. It was an early-­stage cancer. He had it removed, and it never recurred--­a man rescued by anxiety. The moral of this pair of stories is not that emotions help or impede effective thinking but rather that emotions affect thinking: our emotional state influences our mental calculations as much as the objective data or circumstances we are pondering. As we''ll see, that is usually for the best. It is the exception and not the rule when the effect of emotion proves counterproductive. In fact, as we explore the purpose of emotion in this and the next several chapters, we''ll see that, indeed, if we were "free" from all emotion, we would hardly be able to function because our brains would have to be hopelessly cluttered with rules governing the simple decisions we must constantly make to react to the everyday circumstances of life. But for now, let''s focus, not on the detriments or benefits of emotion, but on emotion''s role in the way our brains analyze information.

Emotion states play a fundamental role in the biological information processing of all creatures, in mammals as well as simple insects, and in the actions they take as a result. In fact, the very process that went awry in the Enterprise disaster was mirrored in a controlled experiment in which honeybees were put into an extreme situation eerily parallel to that of the Virgin pilots.3 The researchers in that study were interested in how such simple creatures might respond to being in a chaotic and dangerous situation, and so they subjected them to sixty seconds of high-­speed shaking. How do you subject bees to "high-­speed shaking"? After all, if you simply capture bees in a vessel and shake it, they can hover inside so what you''ll have is bees flying around a shaking jar, not bees that themselves are shaken. To circumvent such issues, these researchers immobilized the bees by strapping them into tiny bee harnesses, adding to the similarity of their plight to that of the Virgin pilots, who were also securely strapped down and immobiliz.