A Haifa childhood
Amos Nathan Tversky was born on March 16, 1937, in Haifa, in what was then British-ruled Palestine. His father, Yosef Tversky, was a Polish-born veterinarian; his mother, Jenia Tversky (née Ginzburg), was a Lithuanian-born Jewish social worker who later served as a member of the Knesset for the Mapai party. He had one sister, Ruth, thirteen years older.
His mother said he taught himself in many areas, including mathematics. In high school he took classes from the literary critic Baruch Kurzweil and became friends with a classmate, Dahlia Ravikovitch, who became an award-winning poet. He grew up as the State of Israel was born, and his own life would be bound up with its wars.
A paratrooper’s courage
After high school Tversky was conscripted into the Israel Defense Forces and served in the paratroopers, rising to the rank of captain. In 1956, as a platoon commander, he led a training exercise watched by the army’s general staff in which one of his soldiers was to blow a gap in a barbed-wire fence with an explosive charge. After lighting the fuse the soldier froze. Tversky ran from cover, reached him and brought him down just before the charge exploded. He was wounded by shrapnel that stayed in his body for the rest of his life; the soldier was unharmed. He was decorated for bravery.
He fought in three wars: he parachuted into combat in the Suez crisis of 1956, commanded an infantry unit in the Six-Day War of 1967, and served in a psychology field unit in the Yom Kippur War of 1973. Daniel Kahneman, who first noticed him in 1957 as a thin, handsome lieutenant in the red beret of the paratroopers, said that Tversky almost never spoke about saving his soldier, but once told him that it had greatly affected him.
Becoming a psychologist
Tversky studied at the Hebrew University of Jerusalem, graduating in 1961, and earned his doctorate in psychology at the University of Michigan in 1965, where he worked with the decision researcher Ward Edwards. His early work was mathematical, on how people choose between options and on the foundations of measurement; he co-wrote a three-volume treatise, Foundations of Measurement, and a theory of choice called elimination by aspects. In 1963 he married the American psychologist Barbara Gans, who became a distinguished Stanford professor in her own right; they had three children.
He returned to teach at the Hebrew University. In 1968 or 1969 his colleague Daniel Kahneman invited him to speak to a graduate seminar about research on how people revise their beliefs. A lively argument followed, the two men met for lunch to compare their hunches about how people “really” judge probabilities, and one of the most celebrated partnerships in psychology began.
Mapping the mind’s shortcuts
Tversky and Kahneman’s method was disarmingly simple: they posed carefully designed questions to students, scientists and professionals, and showed that even experts answered them in predictably mistaken ways. In a landmark 1974 article in Science, Judgment under Uncertainty: Heuristics and Biases, they described three mental shortcuts people use to judge likelihoods. We judge how probable something is by how much it resembles a stereotype (representativeness), by how easily examples come to mind (availability), and by adjusting from whatever starting number we are given (anchoring). Each shortcut is often useful, but each produces systematic errors.
They then turned to decisions. Prospect theory, published in 1979, showed that people evaluate outcomes as gains and losses from a reference point rather than as final states of wealth, and that losses loom larger than equivalent gains. In 1981 they showed in Science that simply rewording the same choice, describing outcomes as lives saved rather than lives lost, can reverse people’s preferences, a phenomenon they called framing. Kahneman wrote that the two men shared a joint mind that was better than their separate minds, and that he probably shared more than half the laughs of his life with Tversky.
Two minds working as one
Kahneman later described the partnership in loving detail. From 1971 to 1972 the two spent a year at the Oregon Research Institute in Eugene, the most productive of Kahneman’s life, working alongside researchers Tversky had known since Michigan, including Paul Slovic and Sarah Lichtenstein. Tversky was a night person and Kahneman a morning person, so they met for lunch and spent long afternoons together, simply talking. To study decisions they invented interesting choices and examined their own preferences; when they agreed, they provisionally assumed others would too. Writing was slow and shared: a day in which they advanced by a sentence or two counted as productive. When Tversky’s fifteen-month-old son, Oren, was told that his father was at work, he volunteered: “Aba talk Danny.”
They resolved every disagreement by discussion until both were satisfied, keeping tie-breaking rules for only two questions: whether a reference should be included, where Tversky had the casting vote, and points of English grammar, which were Kahneman’s domain. Of the eight journal articles they published in their peak years from 1971 to 1981, five had each been cited more than a thousand times by 2002. Kahneman wrote that Tversky’s work was always marked by confidence and a crisp elegance, and that his phrase “Let’s do it right” kept them going through the hardest stretches.
How the work helps people
The MacArthur Foundation summarised Tversky’s research as showing that intuitive judgment and choice often rest on a few simplistic principles that sometimes work well and sometimes produce systematic biases and “cognitive illusions,” and noted that it influenced economics, statistics, law, medicine and business. Medicine is a vivid example. In a 1982 study in the New England Journal of Medicine, Tversky and the physicians Barbara McNeil, Stephen Pauker and Harold Sox showed that patients, students and doctors alike were far more likely to choose surgery for lung cancer when outcomes were described as chances of living rather than chances of dying. The authors suggested that awareness of such effects among physicians and patients could reduce bias and improve the quality of medical decision-making, an insight that bears directly on how risks are explained to patients choosing between treatments.
The same insights became the foundation of behavioural economics and behavioural finance. Prospect theory is regarded as one of the seminal works of the field, and Tversky collaborated with the economist Richard Thaler, among others. Kahneman wrote that their ideas gave legitimacy to the enterprise of building economics on realistic assumptions about how people actually think, and a 1994 review in Science News described their 1974 article as triggering a cascade of research across economics, business, philosophy and medicine. Concepts they named, such as anchoring, availability, framing and loss aversion, are now part of the everyday vocabulary of doctors, policymakers and investors.
Stanford and a wider legacy in psychology
Tversky and Kahneman spent 1977 and 1978 at Stanford, where they completed prospect theory, and in 1978 Tversky joined Stanford’s psychology department permanently, later holding the Davis-Brack professorship in behavioural science. He co-founded the Stanford Center on Conflict and Negotiation, applying the psychology of judgment to the resolution of disputes. He was elected to the American Academy of Arts and Sciences in 1980, received a MacArthur Fellowship in 1984 and was elected to the National Academy of Sciences in 1985.
His own work ranged widely: a theory of similarity, a famous study with Thomas Gilovich and Robert Vallone showing that the basketball “hot hand” is largely an illusion, research on how arguments shape choices, and support theory, a general account of thinking under uncertainty of which he was particularly proud. Kahneman noted that Tversky published more articles in Psychological Review, the discipline’s leading theory journal, than anyone else in its history.
Jewish and Israeli identity
Tversky was a son of Jewish immigrants to Palestine, raised in a family active in building the new state: his mother sat in Israel’s parliament, and he served it as a soldier in three wars. He is described as a Jewish atheist, secular in outlook. He taught at the Hebrew University for years before settling at Stanford, and served in Israel’s army during the wars of 1967 and 1973.
Colleagues remembered him as one of the brightest people they had ever met. A joke among psychologists held that the faster you realised Tversky was smarter than you, the smarter you were. Kahneman called him “the freest person I have known,” and explained that he was able to be free because he was also one of the most disciplined.
Death and the Nobel that was shared in spirit
In early 1996 Tversky learned that he had only a few months to live, with metastatic melanoma. He and Kahneman decided to edit a final joint book on decision-making, and he faced his illness, Kahneman said, with every form of courage. He died on June 2, 1996, at the age of 59.
In 2002 Kahneman received the Nobel Memorial Prize in Economic Sciences for the work they had done together. Nobel prizes are not awarded after death, but Kahneman told reporters that the prize belonged equally to Tversky, and in 2003 the two were jointly awarded the University of Louisville Grawemeyer Award for Psychology. Michael Lewis’s 2016 book The Undoing Project told the story of their friendship to a wide public. Their discoveries, that human error follows patterns and that those patterns can be anticipated and designed around, now help people make better choices about their health, their money and their safety.
Sources & further reading
Daniel Kahneman, Biographical, including Eulogy for Amos Tversky, NobelPrize.org · Amos Tversky, MacArthur Foundation Fellows · On the elicitation of preferences for alternative therapies, New England Journal of Medicine, 1982 (PubMed) · Head of the Class, Stanford Magazine, 2003 · Amos Tversky, Wikipedia · Researched from the sources above and checked against them. Spotted an error? Tell us.
A life of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.