The Undoing Project: A Friendship that Changed the World(36)
Inside the classroom Danny was simply a bold genius. Outside the classroom—well, Avi was surprised by the volatility of Danny’s state of mind. One day on campus, he ran into Danny and found him in a seriously dark mood—unlike anything Avi had ever seen. A student had just given him a bad review, Danny explained, and he thought that maybe he was all washed up. “He even asked me, ‘I’m still the same man, right?’” It was obvious to Avi, and to everyone else but Danny, that the student was a fool. “Danny was the best teacher at Hebrew University,” said Avi, “but it was very hard to convince him that the review didn’t matter—that he was excellent.” This was just the first of many sources of complication for Danny Kahneman: He was unusually inclined to believe the worst anyone said about him. “He was very insecure,” Avi said. “This is part of his character.”
* * *
To those he saw every day, Danny seemed unknowable. The picture people had in their minds of him was ever-shifting, like one of those sketches used for experiments by the Gestalt psychologists. “He was moody in the extreme,” said a former faculty colleague. “You never knew which Danny you were going to meet. He was very vulnerable. Starving for admiration and affection. Very edgy. Very impressionable. But could get easily insulted.” He smoked two packs of cigarettes a day. He’d married, and his wife had given birth to a son and a daughter, but Danny still seemed to others to live entirely through his work. “He was very much task-oriented,” said Zur Shapira, a student of Danny’s who later became a professor at New York University. “You would not say he was a happy person.” His moods put distance between Danny and other people, a bit like the distance caused by intense grief. “Women felt the urge to care for him,” says Yaffa Singer, who worked with Danny in the Israeli army’s psychology unit. “He was always in doubt,” said Dalia Etzion, who served as Danny’s teaching assistant. “I remember coming to him and he was blue. He was teaching, and he said, ‘I’m sure the students don’t like me.’ I thought: What does it matter? And it was bizarre. Because the students love him.” Another colleague said, “He was like Woody Allen, without the humor.”
Danny’s volatility was a weakness and, less obviously, also a strength. It led him, almost inadvertently, to broaden himself. It turned out that Danny never really had to decide what kind of psychologist he would be. He could be, and would be, many different kinds of psychologists. At the same time that he was losing his faith in his ability to study personality, he was building a laboratory in which he might study vision. Danny’s lab had this bench where subjects would be immobilized in a device constructed for that purpose, with their mouths stuck in an impression of their own teeth, while Danny flashed various signals at their pupils. The only way to understand a mechanism such as the eye, he thought, was by studying the mistakes that it made. Error wasn’t merely instructive; it was the key that might unlock the deep nature of the mechanism. “How do you understand memory?” he asked. “You don’t study memory. You study forgetting.”
In his vision lab, Danny searched for the ways people’s eyes played tricks on them. When exposed to vanishingly brief flashes of light, for example, the brightness that the eye experienced wasn’t some straightforward function of the brightness of the flash. It also depended on the length of the flash—was in fact a product of the length of the flash and its intensity. A one-millisecond flash with an intensity of 10X was indistinguishable from a ten-millisecond flash with an intensity of X. But when flashes of light were longer than about 300 milliseconds, the brightness looked the same to people, no matter how long the flash lasted. The point of bothering to discover this was unclear, even to Danny, except that there was demand for such stuff in psychology journals, and he thought that the measuring was itself good training for him. “I was doing science,” he said. “And I was being very deliberate about what I was doing. I consciously viewed what I was doing as filling a gap in my education, something I needed to do to become a serious scientist.”
This sort of science didn’t come naturally to him. A vision lab demanded precision, and Danny was about as precise as a desert storm. In the chaos that was his office, his secretary got so tired of being asked to help him search for his scissors that she tied them by a string to his desk chair. Even his interests were chaotic: That the same person could be mentally following schoolkids into the wilderness to ask them how many people they wanted sleeping in their tent, and sticking grown-ups’ teeth into a vise to study how their eyes worked, struck even other psychologists as odd. Personality testers were hunting for loose correlations between some trait and some behavior: tent choice and sociability, for example, or IQ and job performance. They didn’t need to be precise, and they need know nothing about people as biological organisms. Danny’s studies of the human eye felt less like psychology than ophthalmology.
He nursed along other interests, too. He wanted to study what was known to psychologists as “perceptual defense” but to everybody else as subliminal perception. (A wave of anxiety had swept the United States in the late 1950s, thanks to a book by Vance Packard, called The Hidden Persuaders, about the power of advertising to warp people’s decisions by influencing them subconsciously. Peak craze came in New Jersey, where a market researcher claimed that he had spliced imperceptibly brief messages like “Hungry? Eat Popcorn!” and “Drink Coca-Cola” into a movie and created a surge of demand for popcorn and Coke. He later confessed he’d made it all up.) Psychologists in the late 1940s had detected—or claimed to have detected—the mind’s ability to defend itself from what it ostensibly did not want to perceive. When the experimenters flashed taboo words in front of subjects’ eyes, for instance, the subjects read them as some less troubling word. At the same time, people were also influenced by the world around them in all sorts of ways without being entirely conscious of it: Stuff got into the mind without the mind’s full awareness.