Who are Daniel Kahneman and Amos Tversky? What were their interests and career paths that eventually merged into a revolutionary partnership?<\/p>\n\n\n\n
Over the years, there have been collaborations, such as the Wright Brothers<\/a> or Steve Jobs and Steve Wozniak<\/a>, whose combined influence far exceeded what they would have achieved on their own. In psychology, Michael Lewis suggests that the quintessential duo was Daniel Kahneman and Amos Tversky.<\/p>\n\n\n\n Continue reading to learn about these two men.<\/p>\n\n\n\n\n\n\n\n As individuals, Daniel Kahneman and Amos Tversky were unconventional thinkers<\/a>, but together they amplified each other\u2019s strengths, allowing them to upend behavioral psychology and change the way we understand the foibles of the human mind. We\u2019ll examine Kahneman\u2019s upbringing and early work, followed by Tversky\u2019s parallel path. Then, we’ll take a look at their partnership.<\/p>\n\n\n\n According to Lewis, the more reserved of the two was Daniel Kahneman, who, from an early age, developed an interest in human behavior, particularly in our capacity for error. Born in Tel Aviv in 1934, Kahneman grew up in Paris and was there for the outbreak of World War II. Kahneman and his family fled to the south, where they hid their existence as Jews. It was there, Lewis says, that young Kahneman became a student of other people\u2019s behavior. His father died before the war ended, and Kahneman\u2019s family moved with many others to the future state of Israel in 1946.<\/p>\n\n\n\n A vocational test pointed Kahneman toward psychology, and, while serving in the Israeli army was mandatory, Kahneman was allowed to go directly to college before having to join the armed forces.<\/p>\n\n\n\n Kahneman went to Hebrew University, the only college accessible to him at the time. Because the school was still piecing together its psychology curriculum, Lewis claims that Kahneman essentially had to educate himself.<\/p>\n\n\n\n According to Lewis, the leading field of psychology at that time was Behaviorism, the study of mental conditioning through stimuli and rewards. Kahneman was drawn instead to Gestalt psychology, which suggested that the mind acted as an interpreter between external stimuli and internal perceptions.<\/p>\n\n\n\n Unlike countries in which psychology was purely academic, Lewis suggests that Israel was interested in its practical applications. Upon graduation in 1954, Kahneman joined the army and was assigned to evaluate new enlistees. He noted that the people interviewing recruits were falling victim to the \u201chalo effect,\u201d in which their first impressions colored all following judgments of a candidate. According to Lewis, Kahneman decided to remove human judgment entirely from the process, developing an evaluative \u201cKahneman score\u201d based on new recruits\u2019 documented behavior rather than faulty human perceptions. He found that his department\u2019s evaluations improved.<\/p>\n\n\n\n In 1961, Kahneman earned his doctorate from UC Berkeley and began his postgraduate research at the University of Michigan. There, Lewis says, he discovered a conflict between the thinking mind and sensory perception.<\/strong> Returning to Hebrew University, he continued his research into human vision<\/a> by focusing on what it failed <\/em>to perceive and how it could be tricked.<\/p>\n\n\n\n Amos Tversky couldn\u2019t have been more different from Kahneman. Whereas Kahneman was insecure and sensitive to criticism, Lewis relates that Tversky was energetic, outgoing, and self-assured, with an approach to science characterized by seeing problems through wholly novel angles. Between growing up in Israel, attending school in the US, and returning to his homeland, his academic studies were bracketed by stints of wartime military service.<\/p>\n\n\n\n Tversky was born in Haifa in 1937. Lewis says that, as a boy, Tversky was an athletic thrill seeker. Though he had a natural gift for mathematics, he felt more strongly drawn toward the humanities. He was also brave; in between high school and college, he volunteered as a paratrooper and fought in the war of 1956. (Shortform note: The war of 1956, also known as The Sinai War,<\/a> the Suez Crisis, and the Tripartite Aggression, began when Egypt took control of the Suez Canal in response to a lack of British and US economic aid. In an effort to reclaim the canal, Britain and France enlisted Israel\u2019s aid<\/a> in taking control of the Suez Peninsula.)<\/p>\n\n\n\n Once he was able to attend Hebrew University, Tversky studied psychology, though, according to Lewis, he began to feel that much of its research was unscientific. However, his interest was sparked by a research paper that put forward the process of making decisions as a field of study. Intrigued, in 1961 Tversky enrolled in the Ph.D. program at the University of Michigan, which boasted the world\u2019s premier psychology program. (Shortform note: The University of Michigan\u2019s psychology department grew out of the school\u2019s philosophy program<\/a> in the early part of the 20th century and is still ranked as one of the top psychology schools in the country<\/a>.)<\/p>\n\n\n\n Lewis points out that, until then, decision-making<\/a> had been studied by economists who assumed that people made choices rationally. An implication of this belief was the transitive nature of preference<\/strong>. For example, if a person prefers steak to chicken, and chicken to fish, then they clearly prefer steak to fish. (In math terms, if A>B and B>C, then A>C.) However, Tversky\u2019s research showed that preferences are intransitive<\/em> and that sometimes that same person would choose fish over steak, (C>A). (Shortform note: Despite the evidence supporting Tversky\u2019s view that preference is intransitive<\/a>, there\u2019s still a body of research in favor of the older principle<\/a>.)<\/p>\n\n\n\n Tversky studied under Clyde Coombs, who believed that people evaluating any given choice compare it to an internal idealized image\u2014the perfect steak, or the perfect chicken\u2014and decided based on how closely reality matched their imagined ideal. (Shortform note: Some psychologists believe that similarity judgments based on an idealized image<\/a> govern our choice of romantic partners. In Getting the Love You Want<\/em><\/a>, Harville Hendrix and Helen LaKelly Hunt argue that people fall in love when they meet someone who closely resembles their imagined ideal of their childhood caregivers<\/a>.)<\/p>\n\n\n\n Tversky hypothesized that people make judgments based on \u201cfeatures of similarity,\u201d<\/strong> only taking into account the features that they happen to notice. Lewis points out that Tversky\u2019s approach solved the intransitivity problem by asserting that the features people use to make decisions are dependent on context. For instance, the hypothetical person above might prefer steak if they\u2019re drinking red wine, or they might prefer fish when visiting a place known for its seafood. Tversky\u2019s ideas also predict what\u2019s known as the framing effect<\/a><\/strong>\u2014the principle that decisions can be manipulated by reframing the context in which they\u2019re made. <\/p>\n\n\n\n (Shortform note: The framing effect has been shown to influence individual judgment and public opinion<\/a>. While some people view framing as a useful leadership tool<\/a>, others question whether its use in the political landscape leads to a poorly informed and easily manipulated populace<\/a>.)<\/p>\n\n\n\n This work began the pattern that Lewis asserts would define Tversky\u2019s career\u2014he would examine widely held scientific beliefs, find chinks in their armor, and take them apart. (Shortform note: Tversky\u2019s 1996 obituary<\/a> notes his thought-changing impact on the fields of economics, business, philosophy, and medicine while praising his intellectual rigor and gifts as a storyteller.) <\/p>\n\n\n\n While pursuing his research, Tversky married psychologist Barbara Gans in 1963. He earned his doctorate in 1965 and returned with his wife to teach at Hebrew University, but shortly after, he was called back to duty to command an infantry unit in the war of 1967.<\/p>\n\n\n\n (Shortform note: The Six-Day War<\/a> of 1967 between Israel, Syria, Jordan, and Egypt erupted after years of tension along the countries\u2019 borders and within the West Bank. Israel achieved victory through air superiority<\/a> and tripled in size from lands captured from its neighbors<\/a>. The shock of their defeat reshaped the Arab political landscape and paved the way for the rise of Islamism<\/a>.)<\/p>\n\n\n\n Though their lives had not intersected as yet, when they did finally meet, Kahneman and Tversky sparked in each other an intense collaboration that magnified their individual insights. According to Lewis, Kahneman\u2019s understanding of the fallibility of perception mixed with Tversky\u2019s persistent questioning and mathematical rigor<\/strong> let them demolish the common assumption that human thought is based upon reason.<\/p>\n\n\n\n Though they were colleagues at Hebrew University, their first real interaction took place in 1969 when Kahneman invited Tversky to speak at one of his classes. Tversky discussed research that showed that humans were unconscious statisticians\u2014that guesses people made roughly matched up with mathematical statistical predictions. (Shortform note: The research Tversky referenced related to Bayes\u2019 Theorem<\/a>, a formula for calculating probabilities under varying degrees of information. In 1968, Ward Edwards<\/a> proposed that in uncertain situations, people made guesses as if they were unconsciously using Bayes\u2019 Theorem<\/a>, albeit conservatively<\/a>.)<\/p>\n\n\n\n Kahneman disagreed. He knew from his research that the senses could be fooled. Why not the mind as well? Lewis recounts that Kahneman argued strongly with Tversky, citing the various cognitive errors<\/a> he\u2019d seen his own students make. Tversky was troubled by the doubt he introduced, but, instead of becoming antagonistic, the two psychologists chose to join forces and test whether the subconscious<\/a> uses statistics to make judgments.<\/strong><\/p>\n\n\n\n To investigate their problem, they devised a questionnaire that would pose an array of statistical questions purposefully designed to trip up the people being tested. Lewis writes that their collaborative style was to lock themselves in an office or classroom to hash out the details of their work. People passing by would often hear a mixture of shouting arguments and raucous laughter as the two worked out the various tricks they would embed into their questionnaire. <\/p>\n\n\n\n (Shortform note: While Kahneman and Tversky\u2019s study may seem unorthodox, their methods weren\u2019t. Questionnaires<\/a> are a standard research tool in psychology, allowing scientists to collect information from large groups of people. However, they rely heavily on self-reporting and the subjects\u2019 willingness to provide honest answers<\/a>.)<\/p>\n\n\n\n Instead of inflicting their questionnaire on hapless students, Tversky and Kahneman took it to professional statisticians. The statisticians should <\/em>have answered the questions correctly, yet they didn\u2019t. What\u2019s more, Lewis claims, the mistakes made by trained statisticians were consistent across the board. Chief among these was what Kahneman and Tversky dubbed \u201cThe Belief in the Law of Small Numbers<\/a>,\u201d a cognitive error in which a person assumes that a small sample of information is representative of a larger whole.<\/p>\n\n\n\n According to Lewis, Tversky and Kahneman\u2019s paper on the subject called into question the bulk of social science research because, when conducting surveys across populations, social scientists vastly underestimated the number of participants needed to provide meaningful data. (Shortform note: In How to Lie With Statistics<\/em><\/a>, Darrell Huff argues that an appropriate sample group is large and random<\/a>, while those who use small sample sizes can easily distort their data<\/a> to fit any outcome. In order to avoid the type of error that Kahneman and Tversky identified, researchers today can use a sample size calculator<\/a> to determine how many survey respondents they need to accurately represent a population.)<\/p>\n\n\n\n Meanwhile, says Lewis, a body of evidence was growing that even expert opinions were marred by faulty thinking. Scientists at the Oregon Research Institute began to study how experts actually <\/em>drew their conclusions, as opposed to how they claimed <\/em>they did. In 1970, Tversky went there to further his work, while Kahneman continued his research at home in Israel.<\/p>\n\n\n\nDaniel Kahneman and Amos Tversky<\/strong><\/h2>\n\n\n\n
Daniel Kahneman<\/h3>\n\n\n\n
Amos Tversky<\/h3>\n\n\n\n
The Collaboration Begins (1969-73)<\/h3>\n\n\n\n