Daniel Kahneman
Daniel Kahneman was an Israeli-American psychologist best known for his work on the psychology of judgment and decision-making as well as behavioral economics, for which he was awarded the 2002 Nobel Memorial Prize in Economic Sciences together with Vernon L. Smith. Kahneman's published empirical findings challenge the assumption of human rationality prevailing in modern economic theory. Kahneman became known as the "grandfather of behavioral economics."
With Amos Tversky and others, Kahneman established a cognitive basis for common human errors that arise from heuristics and biases, and developed prospect theory. In 2011, Kahneman was named by Foreign Policy magazine in its list of top global thinkers. In the same year, his book Thinking, Fast and Slow, which summarizes much of his research, was published and became a best seller. In 2015, The Economist listed him as the seventh most influential economist in the world.
Kahneman was professor emeritus of psychology and public affairs at Princeton University's Princeton School of Public and International Affairs. Kahneman was a founding partner of TGG Group, a business and philanthropy consulting company. He was married to cognitive psychologist and Royal Society Fellow Anne Treisman, who died in 2018.
Early life
Daniel Kahneman was born in Tel Aviv, in the British Mandate of Palestine, on March 5, 1934 while his mother Rachel was visiting her family. His parents were Lithuanian Jews who had emigrated to France in the early 1920s; his paternal uncle was Rabbi Yosef Shlomo Kahaneman, the head of the Ponevezh Yeshiva. He spent his childhood years in Paris. Kahneman and his family were in Paris when it was occupied by Nazi Germany in 1940. His father, Efrayim, was picked up in the first major round-up of French Jews, but he was released after six weeks due to the intervention of his employer, La Cagoule backer Eugène Schueller. The family was on the run for the remainder of the war but survived except for Efrayim who died of diabetes in 1944. Kahneman and his family then moved to Mandatory Palestine in 1948, just before the creation of the state of Israel.Kahneman wrote of his experience in Nazi-occupied France, explaining in part why he entered the field of psychology:
Education and early career
In 1954, Kahneman received his Bachelor of Science degree, with a major in psychology and a minor in mathematics, from the Hebrew University of Jerusalem. Israeli intellectual Yeshayahu Leibowitz, whom Kahneman describes as influential in his intellectual development, was Kahneman's chemistry teacher at Beit-Hakerem High School, and Kahneman's physiology professor at university. Kahneman was average in mathematics, but he thrived in psychology. Kahneman was led to psychology when he discovered in his teens that he was more interested in why people believe in God than in whether God exists, and more interested in indignation than in ethics.In 1954, he began his military service in the Israel Defense Forces as a second lieutenant, serving for a year in infantry. He then served in the psychology department of the IDF. He developed a structured interview for combat recruits, which remained in use in the IDF for several decades.
In 1958, he went to the United States to study for his PhD in Psychology at the University of California, Berkeley. His 1961 dissertation, advised by Susan Ervin, examined relations between adjectives in the semantic differential and allowed him to "engage in two of favorite pursuits: the analysis of complex correlational structures and FORTRAN programming".
Academic career
Cognitive psychology
Kahneman received a bachelor's degree in psychology and mathematics from the Hebrew University of Jerusalem in 1954 and a degree in psychology from the University of California, Berkeley, in 1961, and went on to become a lecturer in psychology at the Hebrew University of Jerusalem later in 1961 and was promoted to senior lecturer in 1966. His early work focused on visual perception and attention. From 1965 to 1966, he was a visiting scientist at the University of Michigan, a fellow at the Center for Cognitive Studies and a lecturer in cognitive psychology at Harvard University in 1966 to 1967, and during the summers of 1968 and 1969 he was a visiting scientist at the Applied Psychology Research Unit in Cambridge. His work on attention led to a book, Attention and Effort, in which he presented a theory of effort based on studies of pupillary changes during mental tasks. Kahneman also developed rules of counterfactual thinking, and published "Norm Theory" with Dale Miller.Judgment and decision-making
Kahneman's lengthy collaboration with Amos Tversky began in 1969, after Tversky gave a guest lecture at one of Kahneman's seminars at Hebrew University. Their first jointly written paper, "Belief in the Law of Small Numbers," was published in 1971. They published seven journal articles in the years 1971 to 1979. They flipped a coin to determine whose name would appear first on their initial paper and alternated thereafter. Their article "Judgment Under Uncertainty: Heuristics and Biases" introduced the notion of anchoring. Kahneman and Tversky spent an entire year at an office in the Van Leer Institute in Jerusalem, writing this paper. They spent more than three years revising an early version of prospect theory that was completed in early 1975. The final version was published in 1979 in Econometrica, the leading economic journal at the time. That paper became the most cited in economics. Its success was due to its synthesis of ideas and results discussed at the time about economic behavior under risk in a simple model, whose predictions were systematically supported by psychological experiments.The pair also teamed with Paul Slovic to edit a compilation entitled Judgment Under Uncertainty: Heuristics and Biases that was a summary of their work and of other recent advances that had influenced their thinking. Kahneman was ultimately awarded the Nobel Memorial Prize in Economics in 2002 "for having integrated insights from psychological research into economic science, especially concerning human judgment and decision-making under uncertainty". In the introduction of Thinking, Fast and Slow, Kahneman acknowledges and shares that "our collaboration on judgment and decision making was the reason for the Nobel Prize that I received in 2002, which Amos Tversky would have shared had he not died, aged fifty-nine, in 1996". Kahneman left Hebrew University in 1978 to take a position at the University of British Columbia. In 2021, Kahneman co-authored a book with Olivier Sibony and Cass Sunstein, titled Noise: A Flaw in Human Judgment.
The Harvard psychologist and author Daniel Gilbert said of Kahneman that: "His central message could not be more important, namely, that human reason left to its own devices is apt to engage in a number of fallacies and systematic errors, so if we want to make better decisions in our personal lives and as a society, we ought to be aware of these biases and seek workarounds. That's a powerful and important discovery."
Behavioral economics
Kahneman and Tversky both spent the academic year 1977 to 1978 at Stanford University, Kahneman as a fellow at the school's Center for Advanced Study in the Behavioral Sciences interdisciplinary research lab and Tversky with a visiting appointment at the university's psychology department. Richard Thaler was a visiting professor at the Stanford branch of the National Bureau of Economic Research during that same year. According to Kahneman: "We soon became friends, and have ever since had a considerable influence on each other's thinking." Building in part on prospect theory and Kahneman and Tversky's body of work, Thaler published "Toward a Positive Theory of Consumer Choice" in 1980, a paper which Kahneman called "the founding text of behavioral economics". Richard Thaler obtained a grant from the Russell Sage Foundation to spend the academic year 1984 to 1985 with Kahneman at the University of British Columbia. Together with Kahneman's friend Jack Knetsch they worked on two papers on fairness and on the endowment effect.From 1979 to 1986, Kahneman published multiple articles and chapters. Kahneman published one chapter during the years 1987 to 1989. A few papers on decision making appeared after that hiatus, notably cumulative prospect theory, and an explanation of risk-taking by unrealistic "bold forecasts", but the focus of Kahneman's research from that time was the study of subjective experience.
Variants of utility
Economists distinguish experienced utility—in the sense of Jeremy Bentham and utilitarianism—from decision utility, which is the utility explained by and derived from choices. The experienced utility of an episode is formalized as the temporal integration of momentary utility.Kahneman further distinguished the expected utility from both remembered and predicted utility. Predicted utility is the predicted experienced utility for a future experience. Remembered utility is the evaluation of a past experience. The essential finding of many experiments is that memories of experienced utility are systematically inaccurate. Furthermore, the remembered evaluation of past episodes is the best predictor of subsequent decision utility.
One of the cognitive biases of remembered utility is called the peak–end rule. It affects how people remember the pleasantness or unpleasantness of experiences. It states that a person's overall impression of past events is determined, for the most part, not by the total pleasure and suffering it contained, but by how it felt at its peak and at its end. For example, the memory of a painful colonoscopy is improved if the examination is extended by three minutes in which the scope is still inside but not moved anymore, resulting in a moderately uncomfortable sensation. This extended colonoscopy, despite involving more pain overall, is remembered less negatively due to the reduced pain at the end. This even increases the likelihood for the patient to return for subsequent procedures.