The Undoing Project: A Friendship That Changed Our Minds

Lewis tells the story of how Daniel Kahneman became a psychologist, starting the narrative by chronicling how Daniel, or “Danny,” survived the Holocaust after the German occupation of Paris. As a young Jewish boy in 1942, he was required by law “to wear the yellow Star of David on the front of his sweater” (53). Two years later, his father died, leaving him, his mother, and his sister to figure out how to proceed after Europe had been ravaged by war. In 1946 they moved to Palestine, where Danny’s mother’s family lived. By 1948, Israel declared itself a sovereign state. Thus, by the time Danny was only 14 years old, he had already experienced firsthand the dread of war and the complexity of international politics. Also by this time, “it was clear to all that Danny wasn’t like the other boys. He wasn’t trying to be unusual; he just was ” (63). As Lewis explains, “even at the age of fourteen Danny was less a boy than an intellectual trapped in a boy’s body” (63). His intellectual nature remained with him throughout his high school years and into his university years at Hebrew University, where he bypassed the Israeli military requirements—he had been designated as intellectually gifted—to study psychology.

His decision to study psychology originated after a high school aptitude test identified the field as a suitable vocation for him. From there, Danny developed a particular interest in the behavioral aspect of psychology. He wanted to understand people, most of all himself. Eventually, the Israeli army required him to serve after graduating from Hebrew University and later offered him a job in its psychology unit, which at the time was led by a chemist. Lewis writes, “So Danny, a twenty-year-old refugee from Europe who had spent a meaningful amount of his life in hiding, found himself the Israeli Defense Forces’s expert on psychological matters” (75). During his time working for the Israeli military, he developed a personality test that assigned people to the different branches and positions within the Israeli Defense Forces, and this test has been used right up to the present day. After getting his PhD in psychology at Berkeley, Danny returned to Hebrew University, invigorated and enthusiastic about his field.